PART 1: What is climate change?
Carbon dioxide is the main culprit.
The single human activity that is most likely to have a large impact on the climate is the burning of "fossil fuels" such as coal, oil and gas. These fuels contain carbon. Burning them makes carbon dioxide gas. Since the early 1800s, when people began burning large amounts of coal and oil, the amount of carbon dioxide in the earth's atmosphere has increased by nearly 30%, and average global temperature appears to have risen between 1° and 2°F.
Carbon dioxide gas traps solar heat in the atmosphere, partly in the same way as glass traps solar heat in a sunroom or a greenhouse. For this reason, carbon dioxide is sometimes called a "greenhouse gas." As more carbon dioxide is added to the atmosphere, solar heat has more trouble getting out. The result is that, if everything else stayed unchanged, the average temperature of the atmosphere would increase.
As people burn more fossil fuel for energy they add more carbon dioxide to the atmosphere. If this goes on long enough, the average temperature of the atmosphere will almost certainly rise. You can learn more about how this works, and uncertainties in scientific understanding, from Details Booklet Part 1.
If global warming occurs, not every day or every place will be warmer. But on average most places will be warmer. This will cause changes in the amount and pattern of rain and snow, in the length of growing seasons, in the frequency and severity of storms, and in sea level. Farms, forests, and plants and animals in the natural environment, will all be affected.
Other gases and dust also matter.
Carbon dioxide is not the only gas released by human activities that can cause warming. Human emissions of methane and nitrous oxide together contribute almost half as much warming.
Not all things that enter the atmosphere cause warming. Dust from volcanos, and from human activities, can reflect sunlight (like a window shade) and cool the earth.
Coal and oil contain sulfur. When they are burned the sulfur is transformed into fine particles in the atmosphere. This sulfur pollution contributes to various environmental problems. Most scientists think that sulfur particles cool the planet. In the northern hemisphere, this cooling has partly canceled some of the warming that should have come from the growing concentrations of greenhouse gases. However, since emissions of greenhouse gases continue to grow, and most countries are working hard to reduce emissions of sulfur air pollution, this canceling will probably not continue in the future. In that case, the average temperature may rise more rapidly.
How much warming will there be?
If things go on pretty much as they have been, scientists' best guess is that the amount of warming will be about 2.5°F (1.4°C) by the year 2050. The range of uncertainty stretches from almost no change to over 4°F (2.3°C). Details Booklet Part 1 tells you more about how scientists reach these estimates, how much confidence can be placed in them, and what actions could increase or decrease the size of the change.
The ozone hole is a different problem.
Many people confuse the hole in the ozone layer with climate change. However, these two problems are not closely related. The ozone layer protects the earth from harmful ultraviolet light that can cause skin cancer and damage plants and animals. The main cause of the hole in the ozone layer is chlorofluorocarbons (CFCs), gases that are used in refrigerators, air conditioners, and industrial applications. While CFCs alone cause warming, their ozone destruction can cause cooling. So far these warming and cooling influences have approximately balanced. Prior to 1978 CFCs were used as a propellant in aerosol spray cans, but that use has ended in the U.S. Under an international agreement most uses of CFCs are now being phased out to protect the ozone layer.
PART 2: If climate changes what might happen?
Obviously, climate has a big influence on plants and animals in the natural environment, on oceans, and on human activities, such as agriculture, water supplies, and heating and cooling. The effects of climate change depend upon how much change there is, how fast it occurs, and how easily the world can adapt to the new conditions. Impacts on people.
The effects of climate change on people would change a lot from place-to-place. Economically developed societies, like those in North America, Europe and Japan, could use technology to reduce direct impacts. For example, they might develop new crop varieties, construct new water systems, and limit coastal development. Some northern countries, such as Canada and Russia, might even benefit from longer growing seasons and lower heating bills if the climate becomes warmer.
In contrast, economically less developed societies, like those in parts of Africa, Asia, and South America depend much more directly on climate, and could be hit much harder by sudden or large changes. Places like coastal Bangladesh and low-lying islands, could be flooded by storms or rising sea level. Droughts in Africa might become more serious. Developing countries have far fewer resources for adapting to such changes. They may not be able to afford large projects such as sea walls or aqueducts. Peasant farmers may have difficulty adopting new agricultural practices. The resulting social tensions could lead to more political unrest, large-scale migrations, and serious international problems such as terrorism and wars.
Impacts on nature.
When scientists look at the past they find the natural environment has often adapted to climate changes that have occurred gradually over many thousands of years. However, they also find instances in which changes have occurred rapidly, brought about by events such as sudden shifts in ocean currents. These rapid changes have often caused widespread species extinctions and the collapse of natural ecosystems.
One way to understand the importance of the speed of change is to think about native plants that grow in North America. Global warming could mean that those currently growing in Georgia might be better suited to New England. If climate changes gradually, many plants may be able to "migrate" by spreading seeds into new areas where they can now grow. But if climate changes rapidly, many plants may not be able to spread their seeds far enough to reach the new area. If they die out, so may many of the animals that depend upon them.
Why do scientist disagree about possible impacts of climate change?
Scientists disagree about whether climate change will be a serious problem in the next 50 to 100 years. The main reason for this disagreement is that nobody knows for sure whether climate changes caused by human actions will be large enough and fast enough to cause serious damage. Many scientists believe that they may be. Others argue that if changes occur, the problems they cause will be minor compared with problems caused by today's storms and droughts. You can learn more about these disagreements and the possibility that scientists will be able to resolve them through research, in Details Booklet Part 2.
PART 3: What can be done about climate change?
If carbon dioxide and other gases released by human activities cause climate change, what can people do about it? Three basic strategies are available, abatement, adaptation, and geo-engineering.
Abatement: To abate means to slow or stop. Abatement strategies aim to reduce the emissions of carbon dioxide and other gases that can cause climate change. They include improving energy efficiency, so that we burn less fuel, and using sources of energy that emit no greenhouse gases, such as solar or nuclear power.
Adaptation: Under this strategy people find ways to live successfully with the changed climate. For example, land use may change. Aqueducts can be built to bring water into newly dry areas. Coastal populations can be protected from rising sea level by building dikes and sea walls, by relocating populations inland, and by protecting fresh-water supplies from salt-water intrusion.
Geo-Engineering: Geo means earth, so geo-engineering means to engineer the earth's atmosphere and oceans to reduce the amount of climate change. For example, the amount of sunlight that strikes the earth might be reduced by putting more small particles into the high atmosphere. The idea is to off-set the warming effect of more greenhouse gas by reflecting more sunlight back into space. Many people oppose geo-engineering because they think there might be unintended side effects. However, if rapid and severe climate change occurs, some are likely to press for geo-engineering because it may be relatively inexpensive.
Choosing the appropriate combination of strategies is difficult. Each will cost money, pose problems, and offer benefits. It is unlikely that any single strategy can do the job. Uncertainty is added because scientists do not yet know enough about the costs, risks, and benefits. It is important for researchers to study the options quickly and carefully so that people can make informed choices. You can learn more about what is already known by reading Details Booklet Part 3 in the back of this section.
Common misconceptions about climate change:
Fact: Climate change and the loss of the ozone layer are two different problems that are not very closely connected.
The largest contributor to global warming is carbon dioxide gas released when coal, oil, and natural gas are burned. CFCs, gases which cause stratospheric ozone depletion, play only a minor role in climate change. The depletion of the stratospheric ozone layer, including the ozone hole, is a serious environmental problem because it causes an increase in ultraviolet radiation which can harm people, animals, and plants. This is a different problem from the problem of climate change.
Misconception: Aerosol spray cans are a major contributor to climate change.
Fact: Using aerosol spray cans has almost no effect on climate change.
In the past, aerosol spray cans contained CFCs which contributed to the depletion of the ozone layer (not the same as global warming). Under U.S. law, aerosol spray cans no longer contain CFCs.Misconception: General pollution and toxic chemicals are major contributors to climate change.
Fact: Most forms of pollution play little or no role in climate change. The invisible carbon dioxide released when coal, oil, and gas are burned is the single most important contributor to climate change.
The burning of fossil fuels, such as coal and oil, to produce energy for electricity, heat and transportation is the primary source of carbon dioxide, which is the most important contributor to global warming. Carbon dioxide does not contribute to general air pollution.
Misconception: The space program is a major contributor to climate change because it punches holes in the atmosphere.
Fact: The space program has almost no effect on climate change. The local changes rockets make in the atmosphere soon disappear.
Gases released by rocket exhaust have no real impact on global warming. They have only a small, largely short-term, local effect on the different problem of stratospheric ozone depletion.
Misconception: Using nuclear power causes climate change.
Fact: Nuclear power does not contribute to climate change. If nuclear power is used instead of coal or oil, it will reduce emissions of carbon dioxide. "Renewable energy" sources, such as solar power, can also reduce carbon dioxide emissions.
While nuclear power plants present a variety of other environmental problems, they do not emit gases which contribute to global warming.
sourceDetails Booklet Part 1: More on "What is climate change?"
Details Booklet Part 2: More On "If climate changes, what might happen?"
Details Booklet Part 3 : More on "What can be done about climate change?"
Humanity may not be to blame for global warming after all
Thermometers across the world have recorded a globally-averaged surface warming trend of approximately 0.6C during the 20th century, although much of that trend occurred early in the century, before the major increase in human-caused emissions.
A drawback of the globally-averaged surface temperature record obtained from thermometers is its brevity - the record begins in the mid-19th century. The climate change debate has been fuelled by the misconception that the 19th century is "normal" and that the late 20th century warming trend (about 0.1C per decade) is unusually strong. However, the earth’s climate changes naturally, and this is the backdrop against which the influence of human beings must be judged.
The UK has one of the longest-running instrumental measurements of temperature: the Central England Temperature Record, which started in 1659 and encompasses roughly the area of London, Bristol and Preston. That shows a gradual and natural warming trend of 0.8C over the past 300 years, 200 years before the increase in greenhouse gases.
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The IPCC: Who Are They and Why Do Their Climate Reports Matter?
1. Overview
2. Release Schedule for Fourth Assessment Report*
3. IPCC History and Mission
4. The First Three Assessments
5. IPCC Structure
6. AR4 Products
7. Authors, Contributors, and Reviewers
8. The Peer Review Process
9. Representing a Range of Expert Opinions
10. Consensus Building within the IPCC
11. The Role of Governments
The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) in recognition of the problem of global warming. Through the IPCC, climate experts from around the world synthesize the most recent climate science findings every five to seven years and present their report to the world’s political leaders. The IPCC has issued comprehensive assessments in 1990, 1996, and 2001; its Fourth Assessment Report (AR4) is scheduled for release in 2007.
AR4 will be the most comprehensive synthesis of climate change science to date. Experts from more than 130 countries are contributing to this assessment, which represents six years of work. More than 450 lead authors have received input from more than 800 contributing authors, and an additional 2,500 experts reviewed the draft documents.
AR4 will comprise three sections, or working groups, that deal with the scientific basis of global warming (Working Group I), its consequences (Working Group II), and options for slowing the trend (Working Group III). The IPCC will release summaries of the three working group documents over the course of 2007, culminating in the publication of the final “synthesis report” at the end of the year.
The inclusive process by which IPCC assessments are developed and accepted by its members ensures exceptional scientific credibility. As such, AR4 has the potential to play a key role in informing decision makers as they shape climate policies over the next several years.
Findings of the IPCC Fourth Assessment Report: Climate Change Science
After assessing decades of climate data recorded everywhere from the depths of the oceans to tens of miles above Earth's surface, leading scientists from around the world have reported major advances in our understanding of climate change. Released in February 2007—six years after the prior assessment by the Intergovernmental Panel on Climate Change (IPCC)—the IPCC Fourth Assessment Report’s Working Group I Summary for Policymakers synthesizes current scientific understanding of global warming and projects future climate change using the most comprehensive set of well-established global climate models.
The Working Group I contribution is the first of three that comprise the full IPCC Fourth Assessment Report, which includes the input of more than 1,200 authors and 2,500 scientific expert reviewers from more than 130 countries. In subsequent reports, Working Group II evaluates “Impacts, Adaptation and Vulnerability” and Working Group III evaluates “Mitigation of Climate Change.”
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Findings of the IPCC Fourth Assessment Report: Climate Change Impacts
he second policy-relevant report summary published in 2007 by the Intergovernmental Panel on Climate Change (IPCC) describes the impacts of global warming on society and the natural environment, as well as some of the available options for adapting. Released in April 2007—six years after the prior assessment by the IPCC—the Working Group II Summary for Policymakers is titled Climate Change 2007: Impacts, Adaptation and Vulnerability.
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Findings of the IPCC Fourth Assessment Report: Climate Change Mitigation
There are a variety of strategies available today that, if implemented quickly, can rein in global warming and avoid the most severe consequences. The impact of the more ambitious of these strategies on the world economy is expected to be a fraction of a percent reduction in the annual average growth rate of global gross domestic product (GDP). These are the conclusions of the Intergovernmental Panel on Climate Change (IPCC) Working Group III Fourth Assessment Report published in May 2007.
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global warming solutions
We have the technology and ingenuity to reduce the threat of global warming today. Solutions are already available that will stimulate the American economy by creating jobs, saving consumers money, and protecting our national security. By investing in renewable energy and energy efficiency, and increasing the efficiency of the cars we drive, we can take essential steps toward reducing our dependence on oil and other fossil fuels that cause global warming.
Using energy more efficiently and moving to renewable energy (wind, solar, geothermal, and bioenergy) would significantly reduce our emissions of heat-trapping gases. The United States currently produces 70 percent of its electricity from fossil fuels such as coal, natural gas, and oil, but only two percent from renewable sources. Since the burning of fossil fuels releases large amounts of carbon dioxide—the leading cause of global warming—but renewable energy does not, increasing the share of our electricity generated from renewable resources is one of the most effective ways to reduce global warming emissions.
Cars and trucks are another significant source (25 percent) of U.S. carbon dioxide emissions. A serious effort to address global warming must therefore reduce emissions from cars and trucks. Many technologies already exist that can do this, while also creating new jobs in the U.S. automotive sector and other industries throughout the country. In addition, American consumers would save billions of dollars on gasoline, and we would reduce our dependence on foreign oil.
By putting energy efficiency, renewable energy, and vehicle technology solutions in place at the federal level, we can reduce our contribution to global warming while creating a stronger, healthier, and more secure nation.
sourceWORLD VIEW OF GLOBAL WARMING
THE PHOTOGRAPHIC DOCUMENTATION OF CLIMATE CHANGE
LINKhttp://www.worldviewofglobalwarming.org/index.html
Scientific Facts on Global warming
LINK http://www.greenfacts.org/studies/climate_change/index.htm
Scientific Facts on Climate change 2007
- Part 1: The physical Science Basis
- What makes the climate change?
- How is climate changing and how has it changed in the past?
- How is the climate going to change in the future?
- Part 2: Climate change impacts, adaptations and vulnerabilities
- What impacts of climate change have already been observed?
- What impacts are expected in the future?
- How do people adapt to climate change?
- Part 3: Mitigation of climate change
- What are the current trends in greenhouse gas emissions?
- What actions can be taken to reduce greenhouse gas emissions?
- How can governments create incentives for mitigation?
- Conclusion
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