Down to the wire : confronting climate collapse / David - Index of

18 S politics and governance
carried out by the National Science and Technology Council
(2008), and other scientifi c evidence indicate that our future will
be characterized by: 6
• Rising sea levels by perhaps, eventually, as much as fi ve to
six meters or more, but no one knows for certain. What is
known is that virtually everything frozen on the planet is
melting much more rapidly than anyone thought possible
even a few years ago.
• Higher temperatures almost everywhere, but concentrated in
the northern latitudes, melting permafrost, and boreal forests
turning from weak sinks for carbon into sources of carbon
and methane.
• More drought and severe heat waves, particularly in midcontinent
areas.
• Tropical diseases spreading into regions with previously
temperate climates and emergence of new diseases.
• Degradation of forests and ecosystems due to higher temperatures,
drought, and changing diseases.
• Rapid decline of marine ecosystems threatened by acidifi cation
and higher surface water temperatures.
• Larger (and possibly more frequent) hurricanes, tornadoes,
and fi res.
• Loss of a signifi cant fraction of biological diversity.
Given our past emission of heat-trapping gases, much of this is
simply unavoidable. Regardless of what we do now, the Earth will
warm by another half to a full degree centigrade by midcentury,
bringing us uncomfortably close to what many scientists believe
to be the threshold of disaster. The climate system has roughly a
30-year thermal lag between the release of heat-trapping gases
and the climate-driven weather events that we experience. Hurricane
Katrina, for example, grew from a Class 1 storm to a Class
5 event quite possibly because of the warming effects of carbon
released in the late 1970s. 7 Similarly, the causes behind the weather