Carbon dioxide levels in the atmosphere are pushing 400 parts per million (p.p.m.) — up from the natural pre-industrial level of 280 p.p.m. Emissions for last year were the highest ever. Rather than drift along until a calamity galvanizes the world, and especially the United States, into precipitous action, the time to act is now.
The biology of the planet indicates we are already in a danger zone. The goal of limiting temperature increase to 2 degrees Celsius, as discussed at the Copenhagen and Cancun climate summits, is actually disastrous.
As we push the planet’s average temperature increase beyond 0.75°C, coral reefs (upon which 5 percent of humanity depends) are in increasing trouble. The balance of the coniferous forests of western North America has been tipped in favor of wood-boring bark beetles; in many places 70 percent of the trees are dead. The Amazon — which suffered the two greatest droughts in recorded history in 2005 and 2010 — teeters close to tipping into dieback, in which the southern and eastern parts of the forest die and turn into savannah vegetation. Estimates of sea-level rise continue to climb.
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Thomas E. Lovejoy, The New York Times, 10 June 2011. Full article.
