Global Warming 101: The Science
What is global warming?
Certain gases in the Earth's atmosphere act like the walls of a greenhouse by
holding heat from the sun close to the Earth's surface. This "greenhouse
effect" is a natural process that keeps the planet warm and makes it habitable.
However, since the Industrial Revolution, our society has released increasingly
larger quantities of carbon dioxide (CO2), methane, nitrous oxide, and other
greenhouse gases. Because these gases are collecting in the atmosphere at unnaturally
high levels, the greenhouse effect is causing major changes in the world's climate.
CO2 is the major culprit in climate change. Scientists predict that within 40
years, there may be twice as much CO2 in our atmosphere as there was before the
Industrial Revolution. Deforestation and the burning of coal, oil, and gas for
electricity and transportation are the primary sources of anthropogenic CO2 emissions.
Scientific Evidence
Scientists have proven beyond reasonable doubt that the combustion of fossil
fuels is disrupting the global climate. The Intergovernmental Panel on Climate
Change (IPCC) was formed by the United Nations Environment Programme (UNEP) to
study the scientific evidence about global climate change and its consequences.
It includes more than 2,000 top scientists representing 150 countries, and is
considered to be the most authoritative non-biased scientific voice on the issue.
In its third assessment on climate change, released in October 2000, IPCC scientist's
state that "there is stronger evidence'' than ever before about the human
influence on climate and that it is likely that man-made greenhouse gases already "have
contributed substantially to the observed warming over the last 50 years." The
scientists conclude that if greenhouse emissions are not curtailed, the earth's
average surface temperatures could be expected to increase by 2.6-10.4 degrees
Fahrenheit by the end of this century.
Furthermore, President G.W. Bush commissioned a review of current climate science
by the National Academy of Sciences. Climate Change Science: An Analysis
of Some Key Questions (2001) by the Commission on Geosciences, Environment and
Resources concluded that "Greenhouse gases are accumulating in Earth's atmosphere
as a result of human activities, causing surface air temperatures to rise and
subsurface ocean temperatures to rise."
Even industry representatives and "skeptics" have conceded that the
surface of the earth is warming, and that human activities have contributed to
the trend. The only remaining questions are: "How much more warming can
we expect?" and "How should we address it?"
Local Impacts of Climate Change
The National Oceanic and Atmospheric Administration (NOAA) verified that 15 of
the warmest years ever measured since records have been kept have occurred since
1980, with 1998 being the hottest year on record and 2002 and 2001 being the
second and third hottest. However, global warming does not warm all parts of
the planet evenly, or affect rainfall patterns in the same way across the globe.
Generally speaking, normal climate patterns are changing, thereby disrupting
agricultural practices, disease patterns, and storm frequency and severity. While
no specific storm can be attributed to global warming, some governments have
already begun to point to the extreme weather events of the last few years as
examples of how climate change from global warming has already impacted the planet.
In its 2001 report on the impacts of climate change, the IPCC notes that "inflation-corrected
catastrophe losses have increased eight-fold in North America over the past three
decades".
Recommended Links:
* Learn more about
what climate change is
* EPA:
comprehensive and user friendly
* National Oceanic and Atmospheric
Administration
* Intergovernmental Panel on Climate Change
* United Nations Framework Convention on Climate
Change (UNFCCC)
* U.S. Global Change Research
Program
* Reduce Your Carbon Footprint
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