GLOBAL WARMING
WHAT IT MEANS AND HOW TO STOP IT
Global warming is the increase in the
average temperature of the Earth's near-surface air and
oceans in recent decades and its projected continuation.
Global average air temperature near the Earth's surface rose 0.74
± 0.18 °
C (1.3 ± 0.32 °
F) during the past century. The
Intergovernmental Panel on Climate Change (IPCC) concludes, "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely
due to the observed increase in
anthropogenic greenhouse gas concentrations," which leads to warming of the surface and lower atmosphere by increasing the
greenhouse effect. Based on modeling results, natural phenomena such as
solar variation combined with
volcanoes have probably had a small warming effect from pre-industrial times to 1950, but a small cooling effect since 1950. These basic conclusions have been endorsed by at least 30
scientific societies and academies of science, including all of the national academies of science of the
major industrialized countries. The
American Association of Petroleum Geologists is the only scientific society that rejects these conclusions, and a few
individual scientists also disagree with parts of them.
Climate models referenced by the IPCC project that global surface temperatures are likely to increase by 1.1 to 6.4 °C (2.0 to 11.5 °F) between 1990 and 2100. The range of values reflects the use of differing
scenarios of future
greenhouse gas emissions and results of models with differences in
climate sensitivity. Although most studies focus on the period up to 2100, warming and sea level rise are expected to continue for more than a millennium even if greenhouse gas levels are stabilized. This reflects the large heat capacity of the oceans.
An increase in global temperatures can in turn cause other
changes, including
sea level rise, and changes in the amount and pattern of
precipitation. There may also be changes in the frequency and intensity of
extreme weather events, though it is difficult to connect specific events to global warming. Other effects may include changes in agricultural yields,
glacier retreat, reduced summer streamflows, species
extinctions and increases in the ranges of
disease vectors.
Remaining scientific
uncertainties include the exact degree of climate change expected in the future, and how changes will vary from region to region around the globe. There is ongoing
political and
public debate regarding what, if any, action should be taken to
reduce or reverse future warming or to
adapt to its expected consequences.
Most national governments have signed and ratified the
Kyoto Protocol aimed at combating greenhouse gas emissions.
The
greenhouse effect was discovered by
Joseph Fourier in 1824 and was first investigated quantitatively by
Svante Arrhenius in 1896. It is the process by which absorption and emission of
infrared radiation by
atmospheric gases warms a
planet's atmosphere and surface.
Greenhouse gases create a natural greenhouse effect, without which, mean temperatures on Earth would be an estimated 30 °C (54 °F) lower, so that Earth would be uninhabitable. Thus scientists do not "believe in" or "oppose" the greenhouse effect as such; rather, the debate concerns the net effect of the addition of greenhouse gases, while allowing for associated
positive and
negative feedback mechanisms.
On Earth, the major natural greenhouse gases are
water vapor, which causes about 36–70% of the greenhouse effect (
not including clouds);
carbon dioxide (CO2), which causes 9–26%;
methane (CH4), which causes 4–9%; and
ozone, which causes 3–7%. The
atmospheric concentrations of CO2 and CH4 have increased by 31% and 149% respectively above pre-industrial levels since 1750. These levels are considerably higher than at any time during the last 650,000 years, the period for which reliable data has been extracted from
ice cores. From less direct geological evidence it is believed that CO2 values this high were last attained 20 million years ago. "About three-quarters of the anthropogenic [man-made] emissions of CO2 to the atmosphere during the past 20 years are due to
fossil fuel burning. The rest of the anthropogenic emissions are predominantly due to land-use change, especially
deforestation."
The present atmospheric concentration of CO2 is about 383 parts per million (ppm) by volume. Future CO2 levels are expected to rise due to ongoing burning of fossil fuels and land-use change. The rate of rise will depend on uncertain economic, sociological, technological, natural developments, but may be ultimately limited by the availability of fossil fuels. The IPCC
Special Report on Emissions Scenarios gives a wide range of future CO2 scenarios, ranging from 541 to 970 ppm by the year 2100. Fossil fuel reserves are sufficient to reach this level and continue emissions past 2100, if coal, tar sands or
methane clathrates are extensively used.
Positive feedback effects such as the expected release of CH4 from the melting of
permafrost peat bogs in
Siberia (possibly up to 70,000 million
tonnes) may lead to significant additional sources of greenhouse gas emissions not included in climate models cited by the IPCC.
WAYS TO STOP IT
Don't smoke; use enviormentally safe fuels; in the summertime, instead of turning on the AC, open your windows; in the winter, don't crank the heat to 80. 68 is fine. Simple acts like this can change the world for the better and stop global warming.
Special thanks to Wikipedia, the free encyclopedia for letting me use this information.
