Posted 02/20/2009 - 13:42 by Chris Phoenix
While browsing around New Scientist today, I found several articles related to climate change. Unfortunately, two are bad news, and one is mixed.
Some coal is mined by removing entire mountaintops, dropping jumbled rock into the adjacent valleys. This amazingly destructive practice was banned by a US district court in March 2007. But now a Court of Appeals has reversed the decision. The article does open on a hopeful note: "Even as public opinion in the US turns against coal..."
The second article is about warming in the Arctic. It's been known for a while that the disappearance of the ice cap is exposing darker water, which absorbs more sunlight. This is bad. But recent climate model studies indicate that two other effects are even stronger. First, exposing more water leads to more evaporation - and water vapor is a powerful greenhouse gas. The more humid the atmosphere, the more heat it traps. Second, the exposed water radiates heat to the atmosphere at a higher rate than ice would.
Finally, it seems that Amazon rain forests are soaking up carbon. We learned in grade school that plants remove carbon dioxide from the atmosphere. This is only half the story, because when plants die and are eaten, all that carbon goes right back into the atmosphere. In theory, a mature forest should be carbon-neutral. But the Amazon forest is absorbing 0.6 tonnes of carbon per hectare per year. The article proposes two explanations: first, the rain forests may be still recovering from the effects of earlier pre-Columbian human activity. Second, the forests may be growing more because of the extra CO2 in the atmosphere. I can hear the Business As Usual talking points now: "This means we don't need to save the forests because they're not really old growth, and besides, the extra CO2 is all being taken up by the plants." Sigh...
