Global Warming
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.
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. Natural phenomena such as solar variation combined with
volcanoes have probably had a small warming effect from pre-industrial times to
1950, but a cooling effect since 1950. The 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.
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.
Nenhum comentário:
Postar um comentário