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May 4, 2009 | 22
What is the "right" level of carbon dioxide concentrations in the atmosphere to prevent "dangerous" interference with the climate? In the last two centuries, concentrations have risen to roughly 387 parts per million—and are rising by roughly 2 ppm per year thanks to the more than 30 billion metric tons of CO2 humans put into the atmosphere annually through things like burning fossil fuels and cutting down trees. (That's up from 280 ppm for all of recorded history before the Industrial Revolution.)
Climatologist James Hansen, for one, thinks the answer is 350 ppm. While recent changes are small compared to the massive climate shifts in the Earth's history—as much as 10 degrees Celsius warmer—the reasons for today's shift is different (humans) as is the speed. "Humans are now 10,000 times more powerful than natural geologic changes," Hansen said at a conference this past Saturday organized by students of Columbia University's masters program in climate and society to examine whether (and why) 350 ppm might be the right number. "We're now, unfortunately, in charge of future changes."
Sep 29, 2008 | 1
The results of the first auction of global warming pollution in U.S. history are in: power plant owners are willing to pay just over $3 for every ton of carbon dioxide (CO2) they emit. More than 12 million allowances were sold for $3.07 last Thursday, bringing in $38 million for the renewable energy and energy efficiency programs of the six Northeastern states involved.
A second auction on December 17 will bring all 10 states into the Regional Greenhouse Gas Initiative (affectionately known as RGGI or "Reggie.") But already the 59 bidders in the auction—primarily energy companies but also financial speculators and environmentalists—were willing to buy four times more allowances than were actually on offer; bids came in for a total of 51,761,000 of allowances all told. (An allowance is a permit from the various state governments to emit one ton of carbon dioxide from a power plant.)
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