(44) Climate Science

Examples of Terrestrial Animals

What are terrestrial organisms? What are some examples of them?

Terrestrial Organisms

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Climate Models

Terrestrial organisms

Warmer temperatures have increased growing seasons, with spring arriving earlier and fall coming later for many species of land plants and animals. The second half of the twentieth century saw an increase in growing season of up to two weeks in the mid and high latitudes, with many more frost-free days. The length of a growing season at a single research station in Spain increased by 32 days between 1952 and 2000, and the average increase across Europe was from 1.1 to 4.9 days per decade. Longer growing seasons and warmer temperatures are sometimes accompanied by higher productivity, range changes, and earlier spring and summer seasonal events.

The total effect of growing season length on productivity is unclear. Satellite data show that a lengthened growing season caused increased productivity in the Northern Hemisphere from 1982 to 1991. However, from 1991 to 2002, productivity decreased there, possibly due to hotter, drier summers and more widespread droughts.

Coral Reefs

Coral reefs are known as the “rain forests of the sea” because they harbor such an incredible abundance and diversity of life. These spectacular and beautiful ecosystems are home to more than one-fourth of all marine plant and animal species. Reefs are built of tiny coral animals called polyps that construct calcium carbonate (CaCO3) shells around their bodies. When the larva from a young coral polyp attaches itself to a good spot, usually on an existing coral, and builds a shell, the reef grows. The coral polyps enjoy a mutually beneficial relationship with minute algae called zooxanthellae. In this relationship, the photosynthetic algae supply oxygen and food to the corals, and the corals provide a home and nutrients (their wastes) for the zooxanthellae. The algae give the coral their bright colors of pink, yellow, blue, purple, and green. Coral polyps sometimes feed by capturing and eating the plankton that drift into their tentacles.

Corals can thrive only in a narrow set of conditions. They are very temperature sensitive, so the water must be warm, but not too hot. Water depth must be fairly shallow, with moderately high but constant salinity. The zooxanthellae must have clear, well-­ lit water to photosynthesize. Coral reefs protect shorelines from erosion and provide breeding, feeding, and nursery areas for commercially valuable fish and shellfish.

Damaged coral reefs sometimes turn white, a phenomenon called coral bleaching. First recognized in 1983, coral bleaching has become quite common. When coral animals are stressed, they expel their zooxanthellae. Since these algae give the coral its color, only the white limestone is left when they are gone. Sometimes zooxanthellae move back in when conditions improve, but if they are gone for too long, the corals starve and the reef dies. Coral reefs may recover from one bleaching event, but multiple events can kill them. Disease in corals and some other reef organisms has increased, especially in reefs that are already stressed.

Dr. Clive Wilkinson, coordinator of the Global Coral Reef Monitoring Network, blames the current upsurge in coral bleaching on rising seawater temperatures due to global warming. An increase in summer maximum temperatures of 1.8°F (1°C) for two to three days can trigger a coral bleaching event. If the elevated temperatures persist for less than one month, the reef will likely recover, but sustained heat will cause irreversible damage. After some high temperature episodes, the resident zooxanthellae have been replaced by a more heat tolerant species, and so the reef survives. However, many reefs are already found in the warmest water that zooxanthellae can tolerate, so this process is unlikely to save many reefs in the According to Wilkinson’s report, Status of Coral Reefs of the World: 2004, 20% of coral reefs are severely damaged and unlikely to recover, and another 24% are at imminent risk of collapse.

A wide variety of plants and animals have undergone recent range changes due to rising temperatures. An analysis of more than 1,700 species by Camille Parmesan of the University of Texas, Austin, and Gary Yohe of the University of Middletown, Connecticut, published in Nature in 2003, concluded that there has been a northward range shift of 3.8 miles (6.1 km) per decade. In tundra communities, a shift toward the poles or up mountains may result in a small decrease in range or replacement by trees and small shrubs. North American animals with ranges that are shifting northward include pikas (Ochotona sp.), Rufous hummingbirds (Selasphorus rufus), sea stars (of the class Asteroidea), and red foxes (Vulpes vulpes). Species of plants and animals that have never before been seen in the Arctic are moving in, such as mosquitoes and the American robin (Turdus migratorius). Antarctic plants have increased in abundance and range in the past few decades. Species are disappearing in the lower latitude portions of their ranges. In North America, the Edith’s checker spot butterfly (Euphydryas editha) is almost extinct in Mexico but thriving in Canada. Adélie penguins are now thriving at their southernmost locations but have experienced large population declines where they are found farthest north on the Antarctic Peninsula.

Organisms are also moving up in altitude. Besides contracting in the southern end of their range, many more populations of Edith’s checkers pot butterfly are becoming extinct in the lower elevation portions of their range (40%) than in the highest portions of their range (less than 15%). As a result, the mean elevation of the butterfly has moved upwards by 344 feet (105 m). In the Great Basin of the United States, the lower elevation populations of pika (Ochotona princeps) that were documented in the 1930s were extinct by the early 2000s because the animals have been found to die when the temperature reaches 88°F (31°C) for more than one half hour. In the Alps, native plant species have been driven off mountaintops as they search for favorable conditions and as nonnative plant species move uphill. Migrating animals are changing their ranges. Increasing numbers of European blackcap warblers (Syliva atricapilla) that have traditionally wintered in Africa are now migrating west to Great Britain. Chiffchaffs (Phylloscopus collybita) no longer migrate south, but remain in the United Kingdom for the winter. Of the 57 species of European butterflies Parmesan studied, the ranges of 35 of them were migrating northward: For example, the Apollo (Parnassius apollo), moved 125 miles in 20 years. The Purple Emperor (Apatura iris), unknown in Sweden until the early 1990s, has been increasing its population there. African species, such as the Plain Tiger (Danaus chrysippus), have moved into Spain.

In some species, life cycle events that are tied to day length or temperature are now occurring at different times. The springtime emergence of insects, egg laying in birds, and mating in all animal types is events that have advanced to earlier in the spring. Parmesan and Yoye detected an advancement of spring events of 2.3 days per decade averaged for all species and 5.1 days per decade averaged only for species that showed a change. These changes have been seen in plants, such as lupines (Lupinus sp.); insects, such as crickets and aphids; amphibians; and birds. For example, frogs in eastern North America and in England have been found to breed weeks earlier than they did early in the twentieth century. In mammals, high latitude and altitude species show the most changes. For example, yellow-bellied marmots (Marmota flaviventris) in the Rocky Mountains emerged from their winter hibernation 23 days earlier from 1975 to 1999.

Phenology is relatively easy to study in birds because the animals are visible, and their life cycles are highly regulated by seasonal changes. In many species, temperatures and conditions on the wintering grounds determine spring migration dates. British observers have noted that migratory birds now arrive in their breeding grounds 2 to 3 weeks earlier than they did 30 years ago. The egg laying dates of these birds have also advanced-an average of 8.8 days for 20 species between 1971 and 1995.

In some European flycatchers, the egg laying dates match trends in local temperature. For each 3.6°F (2°C) rise in temperature, the birds lay their eggs two days earlier. Unfortunately, the life cycles of the plants and invertebrates that these birds rely on for food have advanced even more, by about six days for each 3.6°F (2°C) rise in temperature. This timing discrepancy may, at some point, cause problems for the birds because their young will hatch well after their food sources peak. Already in some species, such as pied flycatchers (Ficedula hypoleuca), the number of young birds that hatch each year is smaller.

In some vulnerable locations, changing temperatures have led to the loss of suitable habitats, which is having a dramatic impact on some species. (A habitat is the natural environment of an organism, including the climate, resource availability, feeding interactions, and other features.) The loss of arctic sea ice, for example, is destroying the habitat that is needed by polar bears and northern seals. In the southern edge of their range, where ice is melting and hunting time is reduced, polar bear populations are in significant declines, and their mean body weight is decreasing. In addition, warmer temperatures have caused the populations of ringed seals, the bears’ main food, to decline. In the northern portions of their range, significant numbers of polar bears have drowned because they are unable to swim the greater distances between ice floes. These more northerly polar bears are also experiencing lower reproductive success and lower body weight. The direct effects of temperature changes affect animals differently. Populations of some birds increase when temperatures are high. But, as scientists have learned from El Niño events, when eastern Pacific Ocean temperatures are high, whales have less reproductive success. Some species experience mixed effects: Emperor penguins have greater hatching success when water temperatures rise, but the birds must swim farther from shore to feed, which puts a great strain on them. Also, the instability of ice shelves has reduced nesting success. These competing forces have resulted in a 70% decrease in emperor penguin populations since the 1960s.

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(43) Climate Science

Climate Science: What You Need To Know

CLIMATE CHANGE

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The time of global warming as a controversy is over. Nearly all of the skeptics have come around. Thousands of scientists have gathered and analyzed trillions of bit soft data and constructed sophisticated climate models using the world’s most powerful computers. They have used those models to explain the environmental changes that are now being observed. And they have arrived data consensus. The data, the models, the observations, and the anecdotes all point in the same direction:

Earth is warming, and human activities are largely to blame.

Scientists mostly agree on this point, too:

People must take action on climate change, and they must do it now.

Unfortunately, society has not kept up with the scientists.

News reporters still seek out the few remaining skeptics to provide“balance “to their readers, despite the fact that these doubters have largely been discredited. Political leaders see no advantage in recognizing climate change because it is not relevant on the Short time frame of an electoral cycle.

People are happy to fall back on ideas such as “Well, Earth has been warmer in the past” without knowing what that really means and what the consequences really are. Therefore, while the problem of climate change is moving to the forefront of public consciousness, little organized action has been taken. Ultimately, climate change cannot be ignored. In human history, people have thrived when the weather was good and suffered and died when conditions were too dry, too cold, too hot, or too wet. The Vikings prospered on Greenland during the Medieval Warm Period, while at the same time the Maya civilization was collapsing due to a tremendous drought. But the good times did not last for the Vikings once the Little Ice Age arrived and wiped them out of their northern colonies. Cycles of floods and drought have initiated the spread of disease; the demise of past populations due to bubonic plague provides a chilling example.

Today, people may think that they are above the perils posed by global warming, but they are not. Small increases in temperature may benefit some crops in some regions, but that will not be true in other regions. Larger increases in temperature will hurt agriculture almost worldwide. Storms will increase in frequency and intensity, and sea level will rise, causing tens or hundreds of millions of people to become climate refugees. Vulnerable ecosystems-polar, alpine, and coral reef, to name a few-will disappear, as will the many species that will be unable to escape from, or adapt to, the new conditions. It is very unlikely that human society will be able to maintain its population and its lifestyle under these very different circumstances. But these changes are not yet inevitable.

Climate change is a more difficult environmental problem to understand and to fix than most. When a stream of toxic chemicals flows into a river, fish die. A coal-fired power plant visibly pollutes the air, and trees downwind are harmed by acid rain. These problems are visible and their effects immediate. But the buildup of greenhouse gases in the atmosphere cannot be seen and has no immediate consequences. No single event, even one as destructive as Hurricane Katrina, can unequivocally be attributed to it.

Nonetheless, there is a precedent for dealing with a similar environmental problem-a problem caused by substances that do not outwardly appear to be harmful, that bring about consequences that cannot be seen, and that are international in their effect. The problem was ozone depletion, and the cause was the chlorofluorocarbons and other man-made chemicals that caused it. When atmospheric scientists became convinced that these chemicals were causing the Antarctic ozone hole, the international community responded by phasing out and ultimately eliminating the production of ozone-destroying chemicals. As a result, the rate of increase in the size of the ozone  hole is decreasing, and the hole is likely to start healing by the end of this decade.

Solving the climate change problem will take much more effort and sacrifice than solving the relatively simple problem of ozone depletion. After all, the world economy is built on fossil fuel burning, and many portions of the economy benefit from the destruction of the

rain forests. To start dealing with the effects of climate change, climate scientists recommend that society first work toward becoming more energy efficient, and then work toward converting entirely to energy sources that produce zero carbon emissions. They also recommend reductions in the emissions of other greenhouse gases: For example, changing farming practices to reduce methane emissions and stopping the production of man-made chemicals that contribute to greenhouse warming. Finally, they recommend researching and developing more technologically advanced solutions, such as sequestering carbon and harnessing solar energy in space. The important thing is to start making these changes soon, before the temperature rise to which we are committed becomes dangerous. So far, it has been easy to ignore the environmental effects of climate change, in part because no single incident can be attributed to global warming and because the most serious consequences will not occur until the future. It is easier to deny the contributions people are making to global warming than to recognize and deal with them and make the sacrifices that this will require. The people now in power and those who are now producing most of the greenhouse gas emissions are not the ones who will suffer most of the consequences. The ones who will be most affected by global warming are the young people of today and those yet to be born.

As NASA’s James Hansen said in The New York Review of Books in July 2006, “Who will pay for the tragic effects of a warming climate?

Not the political leaders and business executives I have mentioned. If we pass the crucial point and tragedies caused by climate change begin to unfold, history will judge harshly the scientists, reporters, special interests, and politicians who failed to protect the planet. But our children will pay the consequences.” Because the consequences of global warming will largely be felt by young people, it is especially important for young people to become educated in climate change science and to learn what to do to mitigate climate changes and adapt to them. Young people can voice their dissatisfaction with the political status quo and work to help turn the situation around. It is not too late to begin.

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(42) Climate Science

Hurricane Katrina (2005)

Hurricane Katrina: Facts, Damage & Aftermath

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Step Three: Research and Possibly Develop Some Far-out Ideas

Another idea for reducing rising temperatures is to lessen the amount of incoming solar radiation to reduce the amount of energy that enters the Earth system. There are many possible technologies for accomplishing this, and all would require a great deal of research and development to become usable. One crude idea is to enhance global dimming by purposely placing sulfate aerosols in the upper atmosphere. This strategy has a lot of trade-offs, including increased acid rain and negative health effects from pollution, although it would very likely reduce global warming. Incoming solar radiation could also be decreased by increasing cloud cover through cloud seeding.

A more technological solution is to shadow the planet with large orbiting objects. A 1,243­mile­diameter (2,000-km-) glass mirror manufactured from lunar rock, for example, could act as a sort of sunspot. As it orbited Earth, it would reflect back about 2% of incoming solar radiation to compensate approximately for the amount of heating expected from CO2 doubling. Creating such an object, however, would use a lot of energy.

Tapping into enormous amounts of energy without producing any greenhouse gas emissions is another category of technological solution to global warming. One idea is to place giant photovoltaic arrays on the Moon or in an orbit around Earth. The system would convert solar energy into microwaves and beam the energy to receivers on Earth.

A solar plant outside of Earth’s atmosphere would receive eight times more solar energy than one inside the atmosphere due to the lack of gases, clouds, or dust to block the sunlight. While these panels would be tremendously expensive, the technology could be extremely effective later this century.

For complex technical solutions to be successful in reducing global warming, at least four things are necessary:

The technology must work.

The negative consequences (e.g., environmental damage) of the technology must be minimal.

The technology must be effective enough to combat the effects of continual increases in greenhouse gas levels.

The technology must be less expensive than the cost of reducing emissions at the source.

Individual Contributions

While avoiding dangerous climate change will require coordinated efforts on a global scale, individuals can make a difference by being conscious of what they do, what they buy, and what actions they take. People in the developed world lead energy-intensive lives. Energy is used to power up computers, cook meals, drive to soccer practice, and manufacture consumer goods. Reducing energy consumption reduces greenhouse gas emissions. Limiting the consumption of consumer goods, seeking out more energy-efficient technologies, and avoiding activities that use excessive energy are all steps that individuals can take to reduce their impact. Governments can also assist individuals in being more energy efficient by providing monetary incentives for energy conservation.

Energy-Saving Behaviors

Small actions can lead to big energy savings when a large number of people engage in them. A few guidelines for saving energy are:

Turn electrical appliances off when they are not in use, including lights, televisions, and computers.

Unplug cell phones and other chargers when not in use.

Use precise task lighting at night.

Change old light bulbs to compact fluorescents.

Keep the thermostat set to a reasonable temperature.

Always be conscious of ways to reduce energy consumption.

For example, take showers instead of baths, and only boil the amount of water needed for cooking.

Because most energy consumption is involved with transportation, and because every gallon of gasoline burned emits 20 pounds (9 kg) of CO2 (and many other pollutants), conserving energy in transportation is extremely important. If possible, drive less by living near work or school or by using public transportation. Walking, riding a bike, and carpooling are also good ideas. When driving is necessary, avoid energy-wasting behaviors: Keep the car serviced and the tires inflated, drive within the speed limit, accelerate gradually, and avoid drive-through lines.

Energy-Saving Technologies

Choose technologies that are appropriate for the specific task: For example, a small, fuel-efficient car can transport a family to a soccer game as well as a large sport utility vehicle. A clothesline can be used to dry clothes on a sunny day as well as clothes drier.

Around the house, use energy-efficient appliances and lighting that are operating well. Look for the EPA’s Energy Star when choosing energy-efficient products. When possible, switch to more efficient forms of lighting, heating, and cooling. In the long term, encourage and support energy-efficient building design, including renewable energy technologies such as solar panels. Because manufacturing uses a great deal of energy, try purchasing recycled products, which use less energy than products made from new materials.

Vehicle choice is extremely important. Small, energy-efficient vehicles are preferable to larger “gas guzzlers.” As gasoline prices rise, alternative vehicles become more popular. Hybrid cars are now widely available, and cars powered by liquid natural gas or fuel cells will be more common in the future.

Some activities waste enormous amounts of energy. For example, burning airplane fuel produces greenhouse gases, while airplane exhaust produces ice crystals that trap them. The total warming effect of air travel is 2.7 times that of the CO2 emissions alone. Driving or taking a bus or train presents a good alternative.

Be Politically Active

Work with government at all levels to encourage or require energy-efficient behaviors and technologies. Governments can do many things, including:

Tax energy to encourage conservation and energy efficiency, and to provide funds for research and development of new energy-efficient technologies.

Develop public transportation and increase the safety of biking by building bike lanes and installing bike racks in public places.

Provide tax incentives for households and businesses to adopt more energy-efficient strategies or to convert to carbon-free power sources.

Provide tax incentives for people buying low greenhouse gas-emitting vehicles, while eliminating tax incentives for people buying high-emission vehicles.

Influence energy-efficient development by designing communities that encourage walking and public transportation use.

Individuals can encourage local politicians to take action on reducing greenhouse gas emissions by promoting energy efficiency, mass transportation, and by developing alternative energy sources. Individuals can vote for national leaders who recognize the potential consequences of climate change and will take action. Political leaders can also be encouraged to see that the United States participates in international treaties that seek to limit greenhouse gas emissions.

Offset Carbon Emissions

People can now pay to offset the carbon they produce. An average car produces about 10,000 pounds (4,535 kg) of CO2 per year. To offset that amount, a driver can donate $25 to $50 to a carbon-­neutral organization. The money helps pay for the development of clean power by subsidizing the construction of new wind turbines or solar energy collectors, for example. Planting trees or buying forestland to preserve it is another way to offset carbon emissions. Organizations can counteract their carbon emissions, too: The Rolling Stones offset carbon emissions from a 2003 concert by donating money for planting trees in Scotland, and Ben & Jerry’s ice cream offsets the carbon it produces in manufacturing and retailing. For this strategy to actually offset carbon emissions, the money must fund a project that would not otherwise have been realized.

Buying carbon offsets to counteract greenhouse gas–producing behavior is controversial. Some environmentalists say that buying carbon offsets in conjunction with a conscious effort to reduce an individual’s emissions is a way to increase awareness of the global warming problem while supporting projects that may someday help with the solution. But others say that this market approach does nothing to reduce overall greenhouse gas emissions. While it allows people to feel good about contributing money to offset their carbon footprints, most are still engaging in environmentally destructive behaviors. No matter which side of this issue a person takes, there is no doubt that this is a growing business. Estimates are that people are buying more than $100 million per year in offsets, and that the amount is escalating rapidly.

Adaptation

Even if a radical reduction in greenhouse gas emissions could be rapidly achieved, temperatures would continue to rise due to greenhouse gases that have already been emitted and the thermal inertia in the climate system. How much temperatures rise depends on what mitigation strategies are developed and when they are begun. In the meantime, people, communities, and nations can respond to environmental changes after they happen, or they can anticipate and prepare for the changes.

Communities and nations differ greatly in the resources they have to protect their people from the impacts of climate change. Poor communities already rarely have enough resources to deal with immediate problems, such as poverty. Poor people lack the access to financial and natural resources and social services and, as a result, are often unable to rebuild their lives after a disaster. For adaptation to climate change to work, wealthier communities will have to assist poorer communities in developing their economies while reducing their greenhouse gas emissions and learning to use alternative technologies.

Adaptation before the predicted changes occur has a large cost benefit. Preparing for a disaster is less expensive and less disruptive to people’s lives than mopping up after one.

Hurricane Katrina

Is a tragic example of how planning could have decreased economic costs, the number of lives lost, and the number of those whose lives were disrupted. For decades, climatologists and coastal scientists had warned that a very powerful hurricane could break the levees that protected New Orleans from surrounding water. The levees were designed only to withstand a Category 3 storm. (In the meantime, for a variety of reasons,

the city had sunk to 20 feet [6 m] below sea level in some areas.) Despite these warnings, the recommended improvements to the levees were never made. Hurricane Katrina reached Category 5 as it traveled through the Gulf of Mexico but had dwindled to a Category 3 at landfall and was only a Category 1 or 2 as it passed over New Orleans. Although initially people thought that the city had been spared, the storm’s slow passage over the region was enough to break the levees. The resulting flood left 1,800 people dead while displacing about one million others from their homes. The economic impact is estimated at as much as $150 billion. By upgrading the levees so that they could have protected against a Category 5 hurricane, New Orleans would have been ready for this inevitable storm and the storm surge that accompanied it. This preparation would have been expensive, but compared to the cost of the damage caused when the levees broke, the cost would have been minor.

Other regions can adapt to climate change by recognizing and preparing for their own potential problems. Healthy ecosystems can protect coastal regions, and the original wetlands that once thrived on the Louisiana coast might have spared New Orleans some of the brunt of the hurricane. Hard structures, such as seawalls, are better used sparingly; but soft protection, such as beach nourishment, is wise, although it is very expensive. Increasing the capacity of rainwater storage systems may reduce the number of times a city floods and can be used to save water for drier times. It is necessary for evacuation plans for residents of storm-prone areas to be well thought out, easy to implement, and understandable by all who need them.

Although this is unlikely to happen until the effects of global warming are even more pronounced, coastal scientists recommend that communities retreat from the shoreline, and that new building takes place farther inland. Insurance companies can help to reduce coastal development by increasing rates for those who live in dangerous areas, as they are beginning to do in the hurricane-vulnerable regions of Florida. Federal insurance, which has allowed coastal development to thrive, can also be eliminated (with some compensation for those who own vulnerable property).

London is the first major world city to recognize the need for a detailed climate change adaptation plan. This old but vital city is mostly built on the floodplain of the River Thames, which is a tidal river. Adaptation to higher water levels began in the early 1970s when a movable barrier was built along the Thames to stop flooding from storm surges. In the early years, the barrier was closed no more than two times per year. In most of the years since 1986, the barriers have been closed between 3 and 19 times. The barrier was designed to mitigate sea level rise until 2030. The city is working on plans for what will come next for flood protection and also on plans for other impacts of climate change, including positive ones. For example, planners anticipate an increase in tourism and recreational activities as weather becomes more favorable in the United Kingdom and less attractive in the Mediterranean region. Some small communities are facing inevitable climate change with similar foresight. To adapt agricultural systems to a warmer world, agriculturalists may need to develop crop strains that require less water and less soil moisture. Farms may need to be moved to more climatically hospitable areas. Changing the timing of farming events, such as planting crops earlier, will need to continue. In southern Africa, where droughts have become longer, farmers are making changes such as seeking out crops that are better adapted to the current climate, planting trees to protect the soil, and diversifying their livelihoods.

Adaptation will be an effective response to warming only to a certain extent. If no changes in emissions are made, at some point the environmental changes will likely become too overwhelming, and the costs too great. One example is what could happen to South Florida, where a small increase in sea level would flood some of the lowest lying areas and make the coast more vulnerable to damage from hurricanes and other storms. While people may be able to prepare for these changes or at least mop up after large climatic events, this is very draining when it occurs on the scale of a major city, as has been seen in New Orleans. As sea level rises even higher, the entire southern portion of the state of Florida could flood. If this scenario comes true, at some point Floridians will need to give up trying to patch up the damage and relocate. The economic and social costs of doing this for an entire region are unfathomable.

Society is a long way from mitigating the problem of climate change. Doing so will require the political will to make the necessary changes to reduce emissions at all levels of human organization, from governments down to individuals. Drastically improving energy efficiency is the easiest change to make and can be rapidly initiated. Technological advances in energy use and even in carbon sequestration should be pursued. Over time, more brazen strategies, such as placing solar panels in space, may be possible. The longer action is delayed, the more drastic future changes will need to be. It is predicted that if society delays action for 20 more years, emissions reductions will need to be 3 to 7 times more than if the reductions begin immediately.

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(41) Climate Science

Which major cities are leaders in reducing greenhouse gas emissions

How to Reduce Your Greenhouse Gas Emissions

greenhouse gases

Step Two: Transform Energy Technology

Experts suggest that to substantially reduce greenhouse gas emissions, society must make a massive change in the way energy is produced and used. By the middle of the century, humanity must make a transformation to energy sources that produce zero-carbon emissions.

That is, society must move away from an economy based on the use of carbon-based fuels, called the carbon economy, to an economy based on sustainable energy sources, which are those that can be used without compromising the needs of future generations.

Developing Technologies to Reduce Greenhouse Gas Emissions

Zero­carbon and lower carbon energy sources that are already in use-solar, hydro, wind, geothermal, nuclear, and biofuels-could be improved and in some cases expanded. Solar energy taps the Sun directly rather than indirectly, as with fossil fuels. With the proper technology, solar energy can efficiently heat water or a building. Photovoltaic cells, also known as solar cells, convert sunlight directly into electricity. Solar cells arranged in solar panels on rooftops can provide energy to a building. Producing large amounts of electricity requires building huge arrays of solar cells into panels, parabolic troughs, thermal dishes, or power towers. Solar energy is renewable and produces no pollutants or greenhouse gases. The potential for solar power is enormous, particularly in sunny locations such as the southwestern United States.

Hydropower plants harness the energy of water falling over a dam, which spins the blades of a turbine to produce electricity. Hydroelectric energy is renewable and pollutant and greenhouse gas free. While hydropower produces about 24% of the world’s electricity, it cannot be further cultivated in developed countries because their rivers are almost all dammed. In developing nations, there are still free-flowing rivers that can be dammed, although people sometimes object to hydropower development because the water that backs up behind dams may flood regions that are of scenic or social value.

Wind energy is renewable, is nonpolluting, produces no greenhouse gases, and is widely available. To create usable power, wind turns turbine blades that are connected to a generator that transfers the energy into usable electrical current. Small wind turbines can be placed individually in open areas, but the large-scale use of wind energy requires a wind farm. Wind farms can be located anywhere conditions are good.

Offshore wind farms supply about seven times as much energy in the same amount of area as land-based farms, although the machinery is more prone to corrosion.

Wind energy has enormous potential. Estimates are that wind could supply 40 times the current demand for electricity and about 5 times the global consumption of power. Although wind currently only generates about 1,5% of global power usage, that amount represents more than a fourfold increase between 2000 and 2014. Technological improvements have brought down the cost of building wind plants by 80%, making wind arrays less expensive to build than any other type of power plant. Wind energy is still more expensive to generate than fossil fuel or nuclear power, but when the entire cost to health and the environment is factored in, wind is extremely competitive. New wind farms are being planned all over the world and are increasingly popular in the United Kingdom.

Geothermal energy harnesses the power contained in hot rock below Earth’s surface. Hot water may flow directly from hot springs, or water can be pumped into a region of hot rock and heated. The steam created by the contact of water with hot rock is then used to generate electricity. Geothermal energy is renewable, nonpolluting, and does not emit greenhouse gases. At the world’s largest dry steam geothermal field, located at the Geysers in northern California, sewage effluent from nearby cities is injected into the hot rock found there to create steam.

Research is ongoing on a more advanced geothermal technique, Enhanced Geothermal Systems (EGS), in which boreholes are drilled into rock to a depth of about 6 miles (10 km), a depth routinely drilled by the oil industry. The Massachusetts Institute of Technology reported in 2006 that with improved technology, EGS would be able to supply the world’s total energy needs for several thousand years. The steam from the deep holes could be cycled into an existing coal, oil, or nuclear power plant.

Nuclear energy was nearly dead after the 1979 partial core melt-down at the Three Mile Island plant in Pennsylvania and the 1986 explosion and meltdown at Chernobyl, Ukraine. Several European countries abandoned the use of nuclear power entirely, and the United States and countries in other parts of Europe halted the construction of new nuclear power plants. But concerns about global warming have brought about a resurgence of interest in nuclear power, which is clean and produces no greenhouse gases.

Nuclear power still has many opponents who question several aspects of its safety: Nuclear power plants have a history of accidents, transporting nuclear materials exposes many people to potentially harmful radiation, and the waste generated is hard to dispose of because it remains radioactive for more than 10,000 years. Proponents of nuclear power say that the technology is well developed, and plants could come online quickly, allowing the world to lessen its reliance on fossil fuels rapidly. Plus, they say, the problems associated with nuclear power plants are being solved: New designs reduce the possibility of catastrophic accidents, and development is under way for the safe disposal of long-lived radioactive wastes for more than the required 10,000 years at Yucca Mountain, Nevada, in the United States. Still, this debate is likely to continue for a long time. There are two types of nuclear power. Nuclear fission power plants use enriched uranium as their energy source. Nuclear power is clean, but the uranium it needs must be mined and is nonrenewable. Current estimates are that if fossil fuels were replaced by nuclear fission, there would be only enough uranium to last anywhere from 6 to 30 years. Uranium can theoretically be collected from seawater, but that technology is a long way off. In a breeder reactor, the byproducts of nuclear fission are made to breed new fuel. No country yet has a functioning breeder reactor, although this research is ongoing.

Nuclear fusion takes place when the nuclei of light elements combine to form heavier elements, just as the Sun fuses hydrogen into helium. Energy produced from nuclear fusion is enormously desirable: clean and very efficient. Fusion reactions produce far more energy per unit of fuel than nuclear fission or any other energy source. For example, 0.04 ounces (1 gram) of nuclear fuel holds the same amount of energy as 2,483 gallons (9,400 liters) of gasoline. Once started, fusion reactions are self-sustaining.

Some of the qualities that make fusion energy attractive also make it problematic. The fusion of two isotopes of hydrogen, deuterium and tritium, takes place at enormously high temperatures of about 180 million °F (100 million °C). In a hydrogen bomb, fusion is initiated by the detonation of a fission bomb, and the reactions proceed until the material runs out. Because a reactor cannot be the site of a nuclear bomb detonation and cannot contain such enormous temperatures, scientists are researching the possibility of a process called cold fusion, which occurs at normal temperatures and pressures. Although progress is being made, there is no guarantee that fusion will be able to replace carbon-producing energy in any significant way by the middle of this century.

Biofuels harness the Sun’s energy that is stored in plant and animal tissue. Biomass can be used directly, as when wood, charcoal, or manure is burned to cook food or heat homes. Fuel can also be created by changing the form of biomass. Ethanol, for example, is liquid biofuel produced from plant material and can be burned in cars and other vehicles in place of gasoline. Typical ethanol is produced from plant sugar, such as the sugar in corn. Cellulosic ethanol is made from plant fiber, or cellulose, such as corn stalks. Cellulosic ethanol from crop waste could supply about 25% of the energy needed for transportation in the United States while creating about 85% less greenhouse gases than typical gasoline. Biodiesel is another liquid fuel and can be made from fats such as used cooking oil, animal guts, used tires, sewage, and plastic bottles.

Although biofuels burn cleaner than fossil fuels, they are not pollutant free. Ethanol from corn creates about one-third less greenhouse gases than regular gasoline. Because the CO2 was taken from the environment recently, its addition back into the atmosphere has no net effect (unlike fossil fuels, which emit CO2 that was sequestered). Because they burn more cleanly than fossil fuels, biofuels are used as a gasoline additive in the United States. One fuel, called E85, is 85% ethanol and 15% gasoline. Ethanol fuel is as much as 25% less efficient than gasoline per gallon. Biofuels have limits as an alternative fuel source. Cellulosic ethanol is limited by the amount of suitable agricultural waste, which is far less than the amount of fossil fuels used each year. Growing crops to be made into biofuels is extremely inefficient. For example, because fossil fuels are used extensively in pesticides, in fertilizers, and for performing mechanical labor, there is little or no energy gained from biofuels through using crops such as soybeans or rapeseed. Ethanol derived from corn on a large scale is already credited with increasing food prices because corn is a basic crop in much of the food industry, where it is used in a large variety of products, from animal feed to corn syrup. A 2005 paper by David A. Pimentel of Cornell University and Tad W. Patzek of the University of California, Berkeley, stated that the cornto­ethanol process powered by fossil fuels consumes 29% more energy than it produces. The results for switch grass were even worse, the paper said, with a 50% net energy deficit. Dr. Pimentel said in a 2006 interview in The New York Times, “Even if we committed 100% of the corn crop to making ethanol, it would only replace 7% of U.S.

vehicle fossil fuel use.” Other scientists say that biofuels provide a reasonable alternative to fossil fuels if the right crops are used and ethanol plants become more efficient. Algae contain much more usable oil than land-based crops  and could be fed agricultural and other wastes, although at this time research into algae biofuel is in the early stages.

Fuel cells may someday be used in motor vehicles, but will not be ready for mass production for some time. Fuel cells are extremely efficient at harnessing the energy released when hydrogen and oxygen are converted into water. Fuel cells form the basis of what is known as the hydrogen economy.

A fuel cell is made of an anode compartment (negative cell) and a cathode compartment (positive cell), which are separated by a porous disc known as the proton exchange membrane. A catalyst, which aids in chemical reactions, is located on the membrane. The membrane conducts positively charged ions and blocks electrons. In a hydrogen and oxygen fuel cell, pressurized hydrogen gas is sent into the anode compartment, and oxygen gas is sent into the cathode compartment. At the anode, hydrogen gas is forced through the catalyst and is split into electrons and protons. The protons move to the cathode side, and the electrons are conducted through the external circuit to produce electricity. At the cathode, the oxygen gas is sent through the catalyst and splits into two oxygen atoms. These ions have a strong negative charge and attract the two positively charged hydrogen ions and two of the electrons from the external circuit. The catalyst is dipped into each compartment, which assists in the reaction of oxygen and hydrogen.

The products of this reaction are water vapor and heat. To convert a significant amount of energy, fuel cells must be stacked together. Unfortunately, there are many problems with fuel cell technology. Hydrogen does not exist in vast reservoirs, but must be created. It is also difficult to store and use. One solution is to use a reformer, which turns hydrocarbon or alcohol fuels, such as natural gas, propane, or methanol, into hydrogen. Most of the  current generation of fuel cells runs on the hydrogen in natural gas. But collecting the compound uses up a great deal of energy and, at this time, produces more CO2 than burning the fossil fuel directly. Obtaining hydrogen from natural gas decreases fuel cell efficiency and increases the production of waste heat and gases.

Fuel cell technology is promising in other ways. Besides the incredible efficiency when pure hydrogen is used, the oxygen needed for hydrogen-oxygen fuel cells is widely available in the air. However, while vehicles that run with hydrogen fuel cells create no emissions, they do produce CO2. Unless this gas is sequestered, using hydrogen fuel cells to run vehicles will not solve the global warming problem. Fuel cells that use compounds other than hydrogen are now in development. While the use of fuel cells is still in its infancy, it is now entering a rapid growth phase, with revenue projected to grow to $15.1 billion in 2014. According to the Society of Automotive Engineers in 2007, “Fuel cell energy is now expected to replace traditional power sources in coming years-from micro fuel cells to be used in cell phones to high-powered fuel cells for stock car racing.” Fuel cells are already replacing batteries in portable electronic devices because they last longer and are rechargeable. Even so, many drawbacks remain in developing fuel cells as energy sources, as discussed above. Converting hydrogen to another form of energy requires electricity, which must be generated from conventional energy sources with their typical costs. In a 2005 Science article, a team of Stanford researchers suggests that these costs would be minimized, and pollutants would be negligible, if the hydrogen was pumped into the fuel cells using wind power. The authors state, “Switching from a fossil-fuel economy to a hydrogen economy would be subject to technological hurdles, the difficulty of creating a new energy infrastructure, and considerable conversion costs but could provide health, environmental, climate, and economic benefits and reduce the reliance on diminishing oil supplies.”

Power from coal is so integral to modern society that many energy experts believe that technologies must be developed to make coal burning more environmentally sound. As a result, clean coal, which is more efficient and produces far fewer emissions than normal coal, is becoming an important, but controversial, topic. To produce clean coal, emissions from coal-fired power plants are reduced by gasification. In gasification, the coal is heated to about 2,500°F (1400°C) under pressure to produce syngas, an energy-rich flammable gas. After cleansing, syngas is combusted in a turbine that drives a generator, and then the waste heat powers a second, steam-powered generator.

Syngas burns cleanly and is easily filtered for pollutants. Overall emissions of most air pollutants from syngas are about 80% less than emissions from traditional coal plants. Greenhouse gas emissions, particularly CO2, are also lower. Gasification has other positive features: It makes dirty coal usable, which benefits regions where only dirty coal is available. Also, because the gas is cleansed before it is burned, gasification plants don’t need expensive scrubbers-the devices that eliminate particulates, SO2, hydrogen sulfide, and other pollutants from the waste gases. Clean coal can also be liquefied and burned like gasoline.

Gasification has many downsides. A gasification plant costs 15% to 50% more to build and 20% to 30% more to run than a normal coal-fired plant. Due to these additional costs, conversions to clean coal plants will probably not become widespread until industry is given financial incentives or emissions caps. To produce syngas, gasification uses a great deal of energy, about 10% to 40% more than a standard coal-fired power plant. Also, coal mining is very often environmentally damaging. As yet, although gasification has been tested, it has not been used in a full-scale power plant.

Removing Carbon After It Is Emitted

An alternative to reducing greenhouse gas emissions is sequestering the emissions after they have been created. Carbon can be sequestered in natural systems, or technologies can be developed for carbon sequestration.

Natural carbon sequestration can be enhanced, for example, by reforesting on a large scale. Unfortunately, the opposite is happening as enormous expanses of forest are being cleared for slash-and-­burn agriculture. Forest preservation and reforestation are economically and politically complex issues.

Another approach to sequestration that has been researched is iron fertilization. In those parts of the ocean where the presence of nutrient iron is limited, scientists have discovered that adding iron dust to the ocean stimulates a plankton bloom. The plankton remove CO2 from the atmosphere, although for this to work as a means of sequestering carbon, the plankton must then sink out of the system into the deep sea or into seafloor sediments. While small-scale experiments have confirmed that iron fertilization stimulates plankton growth, no one is certain how large-scale fertilization would affect plankton, or how large-scale blooms would affect the oceans. Recent work has shown that there are few locations in the oceans where the plankton would be removed from the system, and climate scientists currently think that iron fertilization will not make much difference to global warming. Finally, another way to sequester carbon is by increasing the content of organic matter in soils in order to increase the amount of carbon in that soil. Farming techniques that protect soil, such as no till farming and crop rotation, can help sequester carbon.

Artificial carbon sequestration is another possible approach. CO2 from power plants and other large sources can be captured and stored. Carbon is easily captured in gasification plants, where CO2 emissions can be reduced by 80% to 90%, and from natural gas and biofuel plants. Once the CO2 is captured, it is transported by pipelines or by ship to a storage site. CO2 can be stored in rock formations, the oceans, or carbonate minerals. The most promising idea is to inject CO2 into salt layers or coal seams where the gas cannot escape to the surface. (When CO2 is added to nearly spent oil and gas fields, it actually flushes out some of the uncollected oil.) Reports by the Intergovernmental Panel on Climate Change (IPCC) suggest that sites could be developed that would trap CO2 for millions of years, with less than a 1% leakage rate for every 1,000 years.

Several sequestration projects are currently under way. Norway is injecting CO2 from natural gas into a salt formation in the North Sea. CO2 from a coal gasification plant in North Dakota is being used to enhance oil recovery in a reservoir in Canada. British Petroleum is involved in a project in Algeria that will store 17 million tons of CO2.

The Wrong Direction

Besides concerns about greenhouse gas emissions, fossil fuel supplies are dwindling.

Sometime before 2010, society will pass peak oil. Peak oil occurs when half of the oil that was ever available for extraction has already been pumped. Although it might seem that a lot of oil would still be left, what remains is generally lower grade, located in remote locations, and harder to extract. Besides that, if the carbon economy continues unaltered, by 2030 the demand for fossil fuels could be nearly 50% higher than it is today,

largely due to increased use by developing countries: China’s demand is expected to double over 15 years, and India’s may double in 30 years. For all of these reasons, the energy industry is looking for other sources of energy, particularly fossil fuels. Two of these possible sources are oil shale and tar sands.

A rock that contains oil that has not migrated into a reservoir is called an oil shale. Oil shale is mined in open pits. After mining, the rock is crushed, heated to between 840°F and 930°F (450°C and 500°C), and then washed with enormous amounts of water. This entire process creates petroleum, which can then be extracted from the rock. The amount of fuel available as oil shale is comparable to the amount remaining in conventional oil reserves. The United States holds 60% to 70% of the world’s oil shale, mostly in the arid

regions of Wyoming, Utah, and Colorado. These oil shale resources underlie a total area of 16,000 square miles (40,000 km), a little less than the combined area of Massachusetts and New Hampshire. Tar sands are rocky materials mixed with oil that is too thick to pump. Tar sands are strip mined, so many tons of overlying rocks are dumped as waste. Separating the oil from the rocky material requires processing with hot water and caustic soda. Tar sands represent as much as 66% of the world’s total reserves of oil; about 75% of this reserve is in the Canadian province of Alberta and in Venezuela. Extraction of both these sources of oil comes with environmental costs. Both require large amounts of water for processing- by chance, many of these deposits are found in arid areas. Plus, since the oil and tar are spread out, the rock must be mined over a large area. Not only does this degrade the landscape and create a large amount of waste rock, environmental restoration after mining is difficult. As for climate change, extracting usable energy from tar sands produces four times as much greenhouse gas as processing the same amount of conventional oil. This is true to a lesser extent of oil shale as well.

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(40) Climate Science

State of ignorance - climate change and the biosphere (Video)

The Scientist - Climate change and the biosphere

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Effects of Climate Change on the Biosphere scientists

Scientists working in the field of climate change response say that they are already seeing the effects of climate change on living systems. These effects are documented on every continent, in every ocean, across ecosystems, and in every major group of organisms. We discuss the impacts of warming climate on the biosphere-­impacts that match the predictions made by climate change models. Scientists see the effects of climate change on individual organisms, on species of organisms, and on entire ecosystems. Although temperature increases thus far have been small, a large percentage of the species studied have shown some response to climate change.

Effects on organisms

Organisms are adapted to live in particular environmental conditions. Polar bears (Ursus maritimus) need to walk across sea ice to hunt; and corals need water that is warm, with just the right salinity. When conditions change, organisms need to change, or they may die out locally or even go extinct. Scientists who study the effects of global warming on the biosphere have discovered that the processes of evolution do not work fast enough for organisms to adapt to rapidly changing climate. At most, species may evolve a greater ability to disperse into new geographic locations. For example, two species of bush crickets in the United Kingdom evolved longer wings in their northern range boundary. The longer wings allowed the crickets to travel to new territory farther north. The most common response, then, that a species has to warmer temperatures is to move to a cooler location, either higher latitudes or higher elevations. The fossil record indicates that changing latitude or altitude was a common response of organisms to climate change in the past. Of course, this strategy does not always work because the environment in the direction the organisms move may turn out to be unsuitable. Land-based species could find their way to favorable conditions blocked by an impassable ocean or extended out of reach beyond the top of a mountain. The situation is now more complicated than it was in prior Earth history because people have altered the environment with farms, ranches, and cities that may be incompatible with the species’ needs.

A species also may respond to climate change by altering the timing of phases of its life cycle, so that it breeds earlier in the spring, for example. This does not necessarily help it better adapt to the new circumstances; it only reflects the way the species is evolutionarily programmed to respond to weather cues: to breed when the night-time low temperature rises above freezing for several days in a row, for example. The science of how climate influences the recurrence of annual events in the life cycles of plants and animals is called phenology. Some of the findings of phenology as they concern global warming are discussed below.

Freshwater Organisms

Increased temperatures have brought conflicting changes to the aquatic life in some lakes. For example, with a longer growing season and less ice cover, a lake may have more algal growth and therefore higher primary productivity. (Algae are a very diverse group of organisms they are not plants, but most algae photosynthesize.) However, the warm water may remain at the surface, so that there is less mixing of nutrients, which may cause a decrease in productivity.

Warming temperatures have changed the phenology of some freshwater species. In large lakes, the phytoplankton population explodes in the spring, after mixing brings nutrients from deep water to the surface, and when the springtime sunlight becomes strong enough to support photosynthesis. To take advantage of the abundant food, zooplankton populations mushroom just after the spring phytoplankton bloom begins. Now, with spring arriving earlier than in the past, the phytoplankton bloom occurs up to four weeks earlier, but the zooplankton bloom has not kept up. By the time the zooplankton emerges, the phytoplankton populations have already peaked, and the zooplankton starve. Because zooplankton is food for the small fish that serve as food for larger fish, a loss of zooplankton can cause a collapse of the local food web. However, in some lakes, zooplankton populations have increased, and fish populations have grown. Some species of fish, both wild and farmed, have also changed their spring life cycle patterns.

Warming temperatures in rivers have affected the abundance, distribution, and migration patterns of some fish species. In some rivers, warm water species are replacing cold water species. Migrations may take place up to six weeks earlier in some fish populations. Populations that experience such a large change in timing typically suffer higher mortality rates in fish and their spawn.

Marine Organisms

In marine organisms, variations in abundance, productivity, and phenology are strongly influenced by short-term climatic variations, such as the El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). Separating these influences from those due to greenhouse warming is sometimes difficult. Nevertheless, scientists say that several effects are largely due to global warming. NASA estimates that global plankton productivity has decreased at least 6% to 9% in the past 25 years due to rising SST. Warmer temperatures are also causing marine plankton and fish to move toward the poles. One large, recent study found that North Atlantic species moved northward by 10° latitude in 40 years. While overfishing is the cause of the collapse of the once copious North Atlantic cod (Gadus sp.) population, warming temperatures may be working against the species’ recovery.

Recent declines in plankton numbers may be a factor in the poor survival rates of cod larvae. The warming of the air over the Antarctic Peninsula by 4.5°F (2.5°C) in the past 50 years has greatly affected life in the Southern Ocean. Krill (Euphausia superba), an extremely abundant type of zooplankton, form the base of the Southern Ocean food web and are the favorite food of some whales. Since 1976, warming temperatures have reduced the extent of sea ice, which has reduced the habitat required for the ice algae that are a favorite food of the krill. This has been one factor in the 80% decline of krill in the southwestern Atlantic, where they have been historically concentrated. The decrease in

krill numbers has opened up the seas for an increase in salps. These jellylike organisms are not a good source of food for fish and other organisms higher up the food web. As a result, populations of seabirds and seals are in decline.

Many marine plankton species have advanced the timing of their seasonal behavior. Just as in large lakes, when the zooplankton no longer emerge in time to take advantage of the phytoplankton bloom, the zooplankton population suffers. The loss of zooplankton for the food web has negatively affected populations of fish, seabirds, and marinemammals. The migrations of some species of marine animals are also changing; migrations have been found to occur one to two months earlier in warm years.

Nearshore organisms are also showing the effects of warming. In the Pacific, the species found in the intertidal, kelp forest, and offshore zooplankton communities are shifting their ranges due to warmer temperatures. Sea anemones, for example, are moving into California’s Monterey Bay, where the water was previously too cool. The richest ecosystems in the oceans, coral reefs, are being damaged by rising ocean temperatures.

Global Warming Dead Zone

Scientists at Oregon State University are blaming warming temperatures for a dead zone that has formed in coastal waters off the state. As of 2006, the dead zone was 1,234 square miles (1985 sq. km), about the size of Rhode Island. In that year, it made its first appearance in the coastal region of Washington State. The dead zone recurred in 2007 but was not as large or intense as the 2006 event.

A survey by scientists using a remotely operated underwater vehicle found rotting Dungeness crabs (Cancer magister) and sea worms, and a complete lack of fish in the area. “Thousands and thousands of dead crabs and molts were littering the ocean floor, many sea stars were dead, and the fish have either left the area or have died and been washed away,” Professor Jane Lubchenko, who was involved in the study, said in a 2006 press release from Oregon State University.

Oceanic dead zones are caused by extremely low levels of oxygen in a region’s waters. Without oxygen, most marine organisms suffocate. The Oregon dead zone is different from most dead zones, including the much larger one in the Gulf of Mexico. In the gulf, Mississippi River waters carry loads of excess nutrients from fertilizers, detergents, and runoff from feed lots into the water, causing an algae bloom. When these algae die, they are decomposed by bacteria and other organisms that use up all the water’s oxygen.

In the Oregon dead zone, warmer air has changed ocean circulation. In normal years, southerly winds push surface water toward the shore, which keeps deep, nutrient- rich, oxygen-­ poor waters down below. These southerly winds alternate with northerly winds that then push the surface water out to sea. This brings the nutrient-rich, oxygen-poor water to the surface and allows it to mix with the normal surface nutrient- poor, oxygen- rich waters, providing an ideal environment for phytoplankton to bloom (but not over bloom) and support a healthy food web and marine fishery. In dead zone years, all the winds come from the north, and the nutrient- rich, oxygen-poor waters rise to the surface. Plankton bloom and feed off the nutrients, but when they die, they are decomposed by bacteria that take in the oxygen that remains in the water. As a result, oxygen levels dip as low as 10 to 30 times below normal: In one location, they were near zero.

Although they are far from certain, scientists say that changes in the jet stream due to global warming are the likeliest explanation.

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(39) Climate Science

Climate Change - Hurricanes, atolls and coral - Video

Climate Change Impacts - Stronger Storms and Hurricanes

Hurricanes and Climate Change

Practical Action - Climate Change

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Oceans

Warmer air has raised temperatures in the upper levels of the oceans 0.9°F (0.5°C) over the past four to five decades and increased global SST an average of 0.18°F to 0.36°F (0.1°C to 0.2°C) since 1976.

Although the variability of SST is natural, the rise since the 1970s cannot be explained by natural causes. Warming ocean temperatures have resulted in rising sea level, increased erosion, and a change in deep ocean circulation.

Warmer temperatures instigate sea level rise for two reasons: melting ice and thermal expansion. Melting ice from glaciers and ice sheets adds extra water to the oceans, although melt water from ice shelves and sea ice, which float atop the sea, does not. Thermal expansion is a change in the volume of water. Like all substances, water molecules vibrate more vigorously as their temperature increases. The molecules take up more space, causing the water to swell. Although this effect is small, on an ocean wide scale, thermal expansion can swell the sea significantly and result in a sea level rise. Due to thermal expansion and melting glaciers, sea level has risen about eight inches (20 cm) in the past century, and the rate of upsurge has increased in recent years. In June 2006, scientists announced that the sea level rose, on average, 0.1 inches (0.3 cm) per year between 1993 and 2005.

Scientists say that natural variations, such as changing wind patterns and El Niño-Southern Oscillation (ENSO) events, account for only a small part of this increase.

Higher sea level poses a problem during storms because waves and storm surge take place at a level relatively higher to the land. (Storm surge is a local rise in sea level due to winds blowing water up against a shoreline.) Higher storm surge and waves cause flooding, erosion, and the loss of wetlands. Rising seas caused by climate change could destroy half the mangrove forests on some Pacific islands; although, so far, the changing of mangrove forests into shrimp farms has had a far greater effect on tropical coastlines. In the past two decades, 35% of the world’s mangrove forests have been lost.

Globally, 70% of the world’s sandy beaches are eroding. Sea level rise is partly to blame, but other human activities bring greater damage. These include the loss of natural features that protect the shore-line, such as mangrove forests and coral reefs; sediment starvation due to dam construction on rivers; and subsidence due to groundwater pumping. Beach loss is bad for coastal communities, and protecting shorelines has become a major enterprise in the countries that can afford it.

Extreme Weather

Warmer temperatures have increased extreme weather events in their frequency, severity, and longevity. Warmer air holds more water and circulates more vigorously than cooler air, both of which factors are conducive to creating storms. There is evidence that the past

few decades have seen an increase in extreme weather. For example, insurance companies now pay 15 times more money to the victims of extreme weather than they did three decades ago. The total economic losses, including those that are noninsured, are also far greater. One major reason for the enormous increase in economic losses is that there is much more development to which losses can occur, particularly near coastlines.

Heat Waves

The deadliest weather phenomena are heat waves, which have increased in frequency and duration in recent years. A heat wave is a prolonged period of excessively hot weather, relative to what is expected for that location. In temperate zones, a heat wave is considered to be at least three consecutive days of 86°F (30°C) weather, but in warmer regions much hotter temperatures are required.

Despite the prevalence of heating and air conditioning to moderate indoor climate in the developed world, temperature extremes still sometimes lead to lethal results. Health is most impacted when night-time temperatures remain high, and the heat does not subside for days. The increase in pollutants in the stagnant air further contributes to the problem of high temperatures. High heat is also more damaging when coupled with high humidity. The summer of 2003 in Europe was the hottest since 1500. Estimates are that around 26,000 people-nearly 15,000 in France alone-died of heat-related problems. The total cost of the disaster was estimated at $13.5 billion.

Drought

A region is considered to be in a drought if it has had a shortage of rainfall for days, weeks, seasons, or years when compared with how much rain usually falls. Drought is also related to the effectiveness of the rain. For example, if a drought-stricken region receives its entire annual rainfall in one quick storm, the water runs off the land before it can soak into the soil and provide moisture for plants, and the area remains in drought. The National Center for Atmospheric Research in Boulder, Colorado, reports that about 30% of the world’s lands are now stricken by drought, double from the percentage in the 1970s. The southwestern United States has been experiencing drought conditions since 1998.

Floods

While warming has parched some regions, others have experienced increased flooding. There were 10 times as many catastrophic floods between 1990 and 2000 globally than in an average decade between 1950 and 1985. The number of people affected by floods worldwide has risen to 150 million from 7 million in the 1960s. The increase has mostly taken place on the world’s largest rivers. The 1993 Mississippi River flood was the most damaging in United States history due to recent development along the river. The river basin received between two and six times the normal amount of rainfall-so much rain that the ground became too saturated to absorb more water, and local streams began to overflow.

As many as 150 levees, protecting over 6,000 miles (9,300 km) of the Mississippi and its tributaries, failed. However, not all levees broke, and low-lying areas in Davenport, Iowa; Rock Island, Illinois; and Hannibal, Missouri, among others, were saved. At least some of the extreme flooding was caused by the 80% loss of Mississippi River basin wet-lands, which once acted as natural floodwater storage.

Hurricanes

The costliest and most visible change in weather-related disasters in the United States is the increase in the number of intense hurricanes making landfall from the Atlantic basin. Similar increases are also occurring in the Pacific basin.

Hurricanes are born in summer and autumn when a vast area of the sea surface rises to 82°F (28°C) or higher, and winds are light. The warm seawater heats the air above it, causing the air to rise. The column of air spirals upward, feeding on the heat energy from the tropical waters. For the storm to grow there must be little or no wind shear between the lower and upper atmosphere; high wind shear will decapitate the storm.

Hurricanes can grow to 350 miles (600 km) in diameter and 50,000 feet (15 km) in height. Hurricanes are categorized on the Saffir-Simpson scale. Wind speed is highly significant because a storm with 130-miles-per-­hour (209 kph) winds has almost doubled the strength of one with 100-miles-per-hour (160 kph) winds. As a result, although they are only 20% of the storms that make landfall, Category 4 and 5 storms produce more than 80% of the damage from hurricanes. Rainfall of one inch (2.5 cm) per hour is not uncommon in a large storm, and a single hurricane may produce a deluge of up to 22 billion tons (20 billion metric tons) of water a day. Hurricanes typically last 5 to 10 days but may last up to three weeks. Once these mighty storms are cut off from warm water, they lose strength, so they die fairly quickly over cooler water or land.

Damage comes from the impact of these storms on the ocean as well. Category 4 and 5 hurricanes can generate storm surges of 20 to 25 feet (7.0 to 7.6 m) for a distance of 50 to 100 miles (80 to 160 km) along a coastline. Giant waves, up to 50 feet (15 m) high, ride atop storm surges and cause even greater damage. In areas of low elevation-as is typical of the Atlantic and Gulf Coasts of the United States, which rise less than 10 feet (3 m) above sea level-flooding may be devastating.

A typical Atlantic season spawns six hurricanes and many smaller tropical storms. On average, one hurricane strikes the United States coastline three times in every five years (that is, there is a 60% chance of a hurricane striking the coastline in any given year). But few hurricane seasons are typical. A cycle of high activity from the 1920s through the 1960s was followed by low activity between 1971 and 1994. Nevertheless, major storms can form during quiet periods, as was shown when Hurricane Andrew devastated South Florida in 1992.

Since 1995, conditions have become much more favorable for hurricane growth. Between 1995 and 2000, hurricanes formed at a rate twice as great as during the most recent quiet period, and the Caribbean experienced a fivefold increase. Some hurricane experts attribute variations in storm number to natural climate variation, such as the Atlantic Multidecadal Oscillation (AMO), rather than to global warming. Still, many experts blame global warming for other changes in hurricanes. A 2005 study in the journal Nature, by Kerry Emanuel of the Massachusetts Institute of Technology, shows that hurricanes have increased in duration and intensity by about 50% since the 1970s. The number of Category 4 and 5 hurricanes jumped from 50 per five years during the 1970s to 90 per five years since 1995. The jump was even higher in the North Atlantic, from 16 strong hurricanes between 1975 and 1989 to 26 between 1990 and 2004.

Emanuel’s study and others have shown that hurricane number may be related to some other climate oscillation, but that hurricane intensity is related to global warming. Seasons with high SST and global air temperature have intense storms. Rising temperatures also cause these mammoth storms to last longer. These effects of increased storm intensity and duration are predicted by computer models of rising SST.

In the hurricane season of 2005, SST in the critical portions of the Atlantic basin were 1.6°F (0.9°C) higher than was the average between 1901 and 1970. Not surprisingly, perhaps, the 2005 hurricane season has become known as the longest and most damaging season ever (through 2006). The 2005 season lasted weeks past the normal end of hurricane season. There were so many storms that, for the first time, the World Meteorological Organization ran out of the 21 previously chosen names that are available each hurricane season, with the result that six storms needed to be identified by letters of the Greek alphabet. Seven major hurricanes made landfall, resulting in nearly 2,300 deaths and damages of more than $100 billion. Hurricane Wilma was the most intense storm ever recorded, and the third costliest. The costliest, Hurricane Katrina, was the most damaging natural disaster to strike the United States to date. (But not the deadliest: The hurricane that hit Galveston, Texas, in 1900 is estimated to have killed more than 6,000 people. That high death toll was due, in part, to the fact that it took place long before meteorologists were able to predict hurricanes.)

A study by Kevin Trenberth and Dennis Shea of the National Center for Atmospheric Research, in Boulder, Colorado, published in Geophysical Research Letters in 2006, analyzed the reasons the 2005 season was so unusual. It suggests that global warming played the biggest role, with a smaller effect from a Pacific El Niño and a still smaller effect from the AMO. Climate scientists will likely be debating the relative impacts of global warming and other factors regarding hurricanes for years to come.

The United States is not the only location experiencing unusual hurricane activity. In 2004, Japan experienced 10 typhoons, three more than the greatest number ever recorded. Also that year, for the first time, a hurricane formed in the South Atlantic. That storm, called Hurricane Catarina, hit Brazil.

Earth is always changing, on both long and short timescales. Glaciers grow and melt, sea level rises and falls, and hurricanes come and go. But the adjectives are starting to line up: The hottest, driest, wettest, and stormiest weather in history is being experienced in many different locales. These phenomena are pointing in one direction; the effects of global warming are becoming apparent and more intense in the atmosphere and the hydrosphere and such changes are beginning to take a toll on the biosphere. .

 

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(38) Climate Science

Reveal Earth's Atmosphere

Climate Change -UNEP

Climate Change - What is it?

CS35

Effects of Climate Change on the Atmosphere and Hydrosphere

No single event can be attributed unequivocally to global warming: notice melting, not an increase in hurricane intensity, not the bleaching of coral reefs. It is the sum of all of these changes collectively those points very strongly to a world in which global warming is having an increasing effect. The most dramatic impacts being felt so far in the atmosphere and hydrosphere are the melting cryosphere, rising seas, and the rise in extreme weather events.

Many of the observations presented were described in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment. Much of what is presented in the report, and much of what is known about changes caused by warming temperature, comes from studies in the Northern Hemisphere because that is where the scientists are concentrated. Europeans, in particular, have been collecting information over decades and centuries that is useful today.

Cryosphere

Warming at the poles has been much greater than warming in other parts of the globe, a phenomenon due largely to positive feedback mechanisms. The cryosphere is especially sensitive to warming temperature because of the water-ice transition. If the temperature in a tropical forest increases by a few degrees, the forest only becomes warmer. But where water is near its freezing point, a small temperature increase converts solid ice into liquid water. This, in turn, drastically reduces albedo, which further increases warming. Ice does not accumulate as easily on open water as it does on or near other ice. Each winter there is less ice, and the ice that forms is thinner, which makes increased melting likely when summer arrives.

Recent high latitude temperature increases have reduced ice and snow cover in the Arctic region. Satellite mapping of the extent of Arctic sea ice in September shows a 20% drop off since 1979, the first year satellite mapping was done, and an even greater decrease in the past few years. Scientists report that their climate models cannot explain the great loss of sea ice without factoring in human- induced greenhouse gas emissions.

Antarctic sea ice has shown no consistent change in extent at this time. Yet, in parts of Antarctica, ice shelves are collapsing. The largest collapse since the end of the last glacial advance occurred off the Antarctic Peninsula in 2002. The Larsen B ice shelf was 1,255 square miles (3,250 sq. km), about the size of Rhode Island, and650 feet (200 m) thick. Its collapse followed that of the Larsen A in 1995.

Glaciers and ice sheets have been in retreat at least since 1961. Beginning in 2000, the melting rate was 1.6 times more than the average rate of the 1990s, and three times the rate of the 1980s. Glaciers in the low latitudes are retreating most rapidly. Mount Kilimanjaro glacier, immortalized in Ernest Hemingway’s short story “The Snows of Kilimanjaro,” has capped the equatorial African mountain for the past 11,700 years. But this glacier has been retreating for at least a century, perhaps due to a decrease in atmospheric moisture over that part of Africa. More recently, melting due to global warming has added to and speeded up the process. In all, the ice cap shrank from 4.71 square miles (12.1 sq. km) in 1912 to 0.68 square miles (1.76 sq. km) in 2006. Ohio State University’s Lonnie Thompson has witnessed the acceleration of the rate of ice loss and predicts the end of the snows of Kilimanjaro at around 2015. At that time, all that remains of Kilimanjaro glaciers will be in an Ohio State University freezer.

Snowfall has increased in the interior of Greenland and portions of Antarctica, yet ice sheets in both locations are shrinking back. Warmer temperatures melt the ice sheets at their edges, while melt water traveling between the ice sheet and the underlying rock causes the ice to slip at its base and enter the melting zone more rapidly. Between 2003 and 2005, Greenland’s low coastal areas lost about three times more weight in ice than the interior accumulated as snow. The net annual ice melt is equal to the volume of water that flows through the Colorado River in 12 years.

Northern Hemisphere permafrost is thawing, turning portions of the Arctic that were frozen for thousands of years into wetlands. (Wetlands are poorly drained landscapes that are covered all or a large portion of the year with fresh or salt water.)

There is evidence that the southern extent of permafrost in the Yukon of Canada has moved pole ward a distance of 60 miles (100 km) since 1899, although accurate records go back only 30 years. The loss of permafrost intensifies Arctic runoff and erosion because frozen lands are more stable. (Erosion is the transport of sediments from their original location by wind, precipitation, ice, or gravity.) Melting permafrost is a positive feedback mechanism for global warming because it releases methane and other hydrocarbon greenhouse gases into the atmosphere.

Water Cycle and Water Resources

Less water trapped in ice means that more water winds up in the other reservoirs, such as the atmosphere, streams and lakes, and the oceans. Generally, the water cycle is becoming more extreme: Wet regions are becoming wetter, and dry regions are becoming drier. Europe is wetter and is experiencing increased runoff and stream flow. The United States has weathered a 20% increase in blizzards and heavy rainstorms since 1900; the total amount of winter precipitation is up 10%.

By contrast, dry areas have more than doubled in size since the 1970s. Arid and semiarid regions, such as Africa’s Sahel, are experiencing increased drought. Reduced rainfall in the southwestern United States has lowered Colorado River flow to less than it was in the Dust Bowl years of the mid-1930s. For five millennia, the Hamoun wetlands, covering 1,500 square miles (4,000 sq. km) and containing ample water, fish, and game, were a place of refuge for the people of Central Asia. The removal of water for irrigation before it could enter the wetlands, coupled with intense droughts, turned the area into a region of salt flats in 2002.

Warmer air has increased the temperature of surface water in the Northern Hemisphere’s lakes and rivers by about 0.3 to 3.6°F (0.2 to 2°C) since the 1960s. The ice on large lakes and rivers in the mid and high latitudes now freezes nine days later, breaks up 10 days earlier, and is thinner and less extensive than in the past. In some East African lakes, deep water has also warmed, which can affect deep aquatic life. This trend will likely be seen in other lakes.

Warmer temperatures change the thermal structure of lakes. A warm surface layer is not dense enough to sink, so its ability to mix with the colder deeper layers is reduced. This keeps oxygen out of the deep layers of the lake and causes aquatic life to suffer. Water quality also decreases in the lake surface (where most organisms live) as solids, salts, and pollutants collect and are no longer mixed throughout the lake.

Rivers are also experiencing changes due to rising temperatures. Due to shorter winters, snow melts earlier in spring, and river flow peaks earlier in the year. Because communities typically need more water in summer, when there is less rainfall, this shift puts a strain on water supply systems.

Water systems will soon be strained by shrinking glaciers. The people of the Andes Mountains of South America rely on snow and ice melt for their water during the dry summers. Runoff is currently high because the glaciers are melting back at about 328 feet (100 m) per decade. By the end of this decade, however, some glaciers will be gone or too small to provide much melt water. Himalayan glaciers are also melting. These glaciers feed seven rivers that provide more than half the drinking water for 40% of the world’s people.

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(37) Climate Science

Energy efficiency -- The World in 2030

CC34

Mitigation and Adaptation

Climatologists and other scientist’s warmth at significant reductions in green house gas emissions must begin now if dangerous climate change is to be avoided.

The Union of Concerned Scientists Website states, “With aggressive emission reductions as well as flexibility in adapting to those changes we cannot avoid, we have a small window in which to avoid truly dangerous warming and provide future generations with a sustainable world. This will require immediate and sustained action to reduce our heat-­trapping emissions through increased energy efficiency, expanding our use of renewable energy, and slowing deforestation (among other solutions).”

These papers looks at improving energy efficiency, researching and developing different energy technologies, and advancing some technologically unconventional ideas to change the warming trajectory the Earth is now on.

Step One: Improve Energy Efficiency

The easiest and quickest way to reduce greenhouse gas emissions is to radically improve energy efficiency. Encouraging conservation, supporting the use of more energy-efficient technologies, and developing better technologies are some of the ways to reduce emissions of CO2 and other greenhouse gases.

Encouraging Energy Efficiency

Money is often an effective motivator, and economists agree that a good way to encourage energy conservation is with taxes. A carbon tax is a surcharge that is placed on the use of energy sources that release CO2 into the atmosphere. This tax can, for example, be added to the pump price of gasoline or onto the electrical bill for households and businesses that rely on coal-fired power plants. The more energy consumers use, the more tax they pay. The less energy they use, the less their tax bill. The tax gives people an economic incentive to be more energy efficient by driving less, purchasing fuel-efficient vehicles, buying energy-efficient appliances, and keeping the heat turned down.

The money collected can be used for research on alternative fuels and to develop mass transit systems, among other things. Because a carbon tax gives people and companies a financial incentive to conserve energy, industry has an incentive to produce more energy-­efficient vehicles and appliances.

Sweden, Finland, Norway, and the Netherlands all collect carbon taxes. Sweden, for example, requires a user-paid surcharge of $150 per ton of carbon released. Some climate scientists are calling for the establishment of a carbon tax in the United States, and the discussion of a carbon tax has begun in political circles. Opponents say that energy taxes are regressive because they force poor people to pay a larger percentage of their income in tax. But the tax could be made revenue-neutral, meaning that it could be used to offset other taxes paid by the public. For example, a fuel tax that replaced some percentage of income taxes would put a surcharge on people’s behavior instead of on their hard work. People might be given credits if they live far from where they work. The tax could be increased slowly over time, rewarding those consumers who make lasting changes in their lifestyle by, for example, purchasing energy-efficient vehicles and appliances.

Reducing fossil fuel use has the added benefit of reducing the pollution and the environmental degradation that comes from mining coal and pumping and transporting oil. A reduction in oil consumption would also have important economic and political implications, leading to the reduction of both the trade deficit and the nation’s dependence on foreign oil.

In June 2007, the United States Senate approved legislation that requires a 10 mpg (4.25 km/l) increase in the average fuel economy of all vehicles produced over the next ten years. The United States government could go a step further by more rapidly increasing fuel economy standards for its enormous vehicle fleet and requiring increased energy efficiency in government buildings. Requiring better fuel efficiency in such a large market would provide enormous incentive for vehicle manufacturers and many other industries to develop more energy-efficient products. The mass production of more fuel-­efficient products would result in improvements in technology and would make the products available at competitive prices for individual consumers.

Developing Strategies and Technologies That Are Here or Within Reach

Energy cannot be created: It merely changes form. Gasoline, for example, is ancient solar energy that was stored in plants. Transforming energy from one form to another is extremely inefficient. A car burning gasoline, for example, gets only about 20% of the energy contained in the gas the rest is lost as waste heat. Air conditioning systems running on electricity are no better. With this much inefficiency, one fairly easy way to reduce greenhouse gas emissions is to improve technologies to increase energy efficiency.

Transportation is the largest user of energy in the United States. Fuel efficiency is related largely to a vehicle’s weight: The heavier the vehicle, the more energy is needed to propel it, and the more energy gets wasted. Encouraging people to drive smaller, lighter cars can help. Research is going into constructing vehicles of the light weight carbon composite used in race cars that could operate with a smaller, lighter engine and a lighter drive train and assembly. Estimates are that a car built of these materials could weigh 65% less than a modern passenger car, which would greatly improve fuel efficiency.

Hybrid vehicles are already available and are increasing in popularity. Hybrids run the energy lost during braking through an electric motor and into a rechargeable battery. Energy from the battery then boosts the car during acceleration and uphill travel. Because of the additional energy source, hybrids have smaller engines and so are lighter than conventional cars. Some hybrid cars get nearly 50 mpg (21 km per liter). In the near future, hybrid cars will have large batteries that can be plugged into an electrical outlet overnight to increase the charge available for the next day’s driving.

Reducing energy consumption also reduces emissions of some non-CO2 greenhouse gases, and most can be reduced in other ways as well. Chlorofluorocarbons (CFCs) have already been phased out in developed nations and are being phased out in developing countries because of the damage they do to the stratospheric ozone layer: Their contribution to global warming will be negligible by about 2050.

Some known agricultural practices can reduce methane (CH4) emissions. Rice farmers can use certain plant strains, fertilizers, and only intermittent irrigation. Better feed can reduce CH4 emissions from cows, goats, and sheep. Techniques to keep methane from escaping landfills, coal and oil mines, and waste management lagoons are being developed. Because methane is an energy source, CH4 can be captured from landfills or animal wastes and converted to electricity.

This technology was pioneered in the United States more than 20 years ago and is now widely used in Europe and elsewhere. Improving energy efficiency is an important part of reducing greenhouse gas emissions. During the energy crises of the 1970s, when fuel from the Middle East was restricted for political reasons, automakers nearly doubled the average efficiency of automobiles, and global growth of CO2 fell from 4% per year to between 1% and 2%. Because Europe emits half as much CO2 per unit of GNP as the United States, a large improvement in energy efficiency should be easily attainable. Developing countries such as China and India produce much more CO2 per unit of GNP than the developed countries; but with technological assistance, they could easily lower their CO2 emissions per unit of GNP.

Still, according to the report Avoiding Dangerous Climate Change, improvements in energy efficiency cannot make up for increases in energy use in the developing nations due to their burgeoning populations and economic growth. In the long run, even greater reductions in emissions will be needed to control greenhouse warming. The next step, then, must be a shift from away from a carbon-based economy.

 

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