Plant a tree, make things worse

Jeremy Bruno, one our newest ScienceBloggers, hit the nail on the head with a post about the folly of assuming that we can do about something climate change by planting more trees, at least in the non-tropical regions. This is not a new idea, and studies pointing out that lowering the albedo of snow-prone northern latitudes by increasing forest coverage more than offsets any increased carbon uptake by those very same trees have been coming out every few months for at least six years now. What I like about Jeremy's take is his observation that tree-planting advocates are symptomatic of the fact that

... far too many "green" bloggers [are] boiling things down to simplistic problems and simplistic results; they are committing the same sin as the detractors of conservation. We will accomplish nothing simply by switching to cloth diapers and fair trade coffee.... These things might be helpful in changing people's minds, perhaps, but they are a drop in the bucket compared to the necessity of studies like these.

About five years ago, I was taking part in a telephone press conference with what was then Canada's negotiating team at an Kyoto Protocol implementation session. Canada was demanding credit (against its carbon emissions) for its forests, and future credits for planting more trees. I pointed out (way back then) that studies in journals as prestigious as Nature , by scientists in prestigious labs like those run by Duke University, were blowing the whistle on the northern latitude albedo effect from forest cover, and asked if Canada's wasn't running the risk of making things worse rather than focusing on genuine efforts to reduce emissions. The negotiators said they weren't aware of any such studies and were surprised I would even suggest that planting tree isn't a good thing. I didn't get a chance to follow up.

Fortunately, Canadian officials have since given up trying to get credit for forest cover -- the science is becoming quite clear on the net effects. Of course, there still is much research to be done, as this sort of thing isn't amenable to back-of-the-envelope calculations. But Jeremy highlights the lesson well: climate change is a complicated thing, and those who don't understand the science, whether they're federal negotiators charged with figuring out how to save the planet, or a lone citizen trying to do his or her small part, should take great care before embracing schemes that appear to offer easy solutions.

There is no free lunch. I wrote about the problems with relying on carbon offsets, including tree-planting, a little while ago. And as Fred Pearce wrote recently in New Scientist:

What does seem fair criticism is that efforts to portray offsets as simple, quick fixes pose serious questions of both commercial and ecological legitimacy.

What really troubles me is the veritable chasm between the minor changes in consumer habits being advocated by naive environmentalists and the revolution in the industrial economy required to forestall the worst effects of global warming just doesn't seem to be shrinking fast enough.