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5 Myths and Misunderstandings about Global Warming. Myth#1: Scientists are still debating over whether Global Warming is real. Reality#1: - PowerPoint PPT Presentation
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5 Myths and Misunderstandings
about Global Warming
Myth#1:Scientists are still debating over whether Global Warming is real.
Reality#1:Scientists are not debating over whether Global Warming is real. They are now debating about the rate at which global change is occurring. The scenarios being debated range from catastrophic abrupt change to a gradual shift in temperature over the next 100 or so years.
Some world leaders still believe it’s a myth
Myth#2:Emissions of greenhouse gases from human activities are so tiny in comparison with natural sources that humans can't have any effect on climate.
Reality#2:Natural sources of heat-trapping greenhouse gases like carbon dioxide are largely balanced by natural "sinks" for greenhouse gases, like oceans and forests that remove the gases from the atmosphere by absorption. People are adding more to the atmosphere than these sinks can absorb and at the same time are removing the forests.
Myth#3:Rising emissions of greenhouse gases will stimulate plant growth, acting as a natural brake on global warming as thriving crops and forests absorb more carbon dioxide out of the atmosphere.
Reality#3:Although studies have shown that carbon dioxide does indeed stimulate plant growth, nature is more complicated than the laboratory. Increases in carbon dioxide may cause some plants to be less nutritious to humans and animals. Most studies also point to the increased risk of droughts from global warming in the key agricultural regions of the world. These changes in rainfall patterns may override any benefits from increased carbon dioxide.
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Myth#4:We can't even predict next week's weather accurately, so computer models can't possibly forecast global warming.
Reality#4:Climate models are very different from the models used by daily weather forecasters. They are on a global scale and are used to simulate past and future average weather conditions over long timeframes, like 100 years. The climatic changes that the models have "predicted" for the 20th century correspond well with actual observed changes in temperature and precipitation. The six warmest years on record have all occurred in the 1990s. Global mean sea level has risen by 10 to 25 cm over the last 100 years. Along the U.S. Gulf and Atlantic shores, sea level has risen about 30cm in the last 100 years. Mountain glaciers around the world are melting, permafrost in the Arctic is thawing, and Antarctic ice sheets are breaking up.
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Myth#5:The hole in the Ozone Layer has a big effect on Global Warming.
Reality#5:There is no direct link between the formation of the ozone hole and the greenhouse effect. Emissions from fossil fuel burning (CO2) lead to the greenhouse effect but not to the ozone hole.
Since ozone prevents high intensity ultra-violet radiation from reaching the surface of the Earth and causes stratospheric warming, the ozone hole does change the total radiation budget of the Earth. However, ozone depletion and the formation of the polar ozone holes doesn't lead to a further warming of the troposphere, but to a slight cooling.
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What can we do??
• Top Ten from a generic information site.
• A list from scientist• The Final Word…for right now.• No this has to be the Final Word.
The debate is on...All ERM students will be initially looking at both sides of a debate on the question:Should we take action on Global Warming?Everyone has to produce a research report. In class debates for all 4M students who are in 3U or 4U English are compulsory. 4E/3C/4C students will be providing added research for the debaters. Final details on the report format will follow tomorrow.
