Global warming and cooling in the future
Here are the central points of the preceding material;
The ice record goes back more than 400,000 years. Atmospheric carbon dioxide concentration never exceeded 300 ppm in all that time. It was usually much lower. Now the concentration is 379 ppm and 600 ppm and even 900 ppm seem possible by the end of the century. Knowing this, and knowing the role that carbon dioxide plays in the greenhouse effect, must be alarming.
It is impossible to know precisely what will happen to the Earth's climate. The models are not very good and they require good data which are hard to get.
But a few things can be said. A 1°C or 2°C global temperature increase applied for 1 or 2 centuries will have a profound effect. That is enough to cause the icecaps of Greenland and Antarctica to melt and the oceans to rise. Some northern areas could become farmland while the Sahara might become bigger. Many plants and animals will find themselves in climates they are not suited for. Storms may become more intense.
A temperature rise of a few degrees will change the appearance of the globe. A temperature rise of a few degrees will cause the Earth's oceans to rise by 5 meters. That is enough to put almost half of Florida under water as this map illustrates. Some countries would disappear including Bangladesh and the Netherlands. (Water added to the ocean from melting icecaps is not the primary reason for the rising oceans. The reason is the increase in volume that results from warming the ocean.)
Climate is obviously a universal concern. The findings of scientists that lead to the predictions need to be widely understood.
 In 1988 the
United Nations established the IPCC (Intergovernmental Panel on Climate Change).
The IPCC is fundamentally a scientific body although the UN is a political
institution. Leading scientists from around the world make up the IPCC. In 2001,
the IPCC published a report called Climate Change 2001: The Synthesis Report.
It is available online. You can download all of it or single chapters. There are two summaries; one is technical and one is for policymakers. You can see
The Synthesis Report
and related reports at:
 http://www.pbs.org/wgbh/warming/ In "What's Up with the Weather?" NOVA and FRONTLINE join forces to investigate the science and politics of one of the most controversial issues of the 21st century: the truth about global warming. Click on water world.
http://www.giss.nasa.gov/research/impacts/ NASA/Goddard Institute for Space Studies. The Antarctic ice core data is from a very readable presentation called Can We Defuse the Global Warming Time Bomb? given in June 2003 by James Hansen. This is a 1.5 megabyte PDF report. Look at the list of science briefs.