Seeing the forrest for the Albido?

Submitted by GregoryHeller on January 29, 2007 - 8:29pm.

It used to be so easy, just a few months ago it seemed that planting trees would be enough to offset my carbon footprint and, at the same time, help prevent soil errosion and other enviornmental problems in degraded environments.

Not any more, Hope called my attention to this post on Grist that talks about a recent study showing mixed results of tree planting in battling global warming. While trees do absorb Carbon, they also absorb heat from the sun. As you approach the poles, it seems that trees might do more harm than good. And especially as the polar sea ice melts. Darker surfaces (green trees, and dark ocean waters) will absorb more of the suns rays compoundning the global warming problem.

The BBC just ran a story on the World Service radio program that discussed just this dilemma (though I cannot find the link).

So I guess that this year, instead of buying more trees, I'll buy some carbon offset credits.

UPDATE: Those who know me know I am a man of action, and integrity, I just decided to get myself a Terra Pass both for flight (40k pounds for $149) and driving. Since I use car sharing, rentals, or borrow various cars when I drive mostly, I just got the Cross Towner (for $39) which offsets about 8k pounds of C02, about 12k miles.

The way I calculated my flight pass was a little imprecise, I said 8 Seattle to NY round trips, a few Seattle to San Franciscos, a Seattle to Palm Beach, and a Seattle to New Orleans. If figure at the end of the year, I'll work out all my travel and make up the difference. These offsets are added to last years purchase of 1000 Trees which are supposed to remove 50k pounds of C02 a year for 40 Years.

Learn more Terra Pass.

Same concern
Submitted by Leithauser on January 30, 2007 - 4:31pm.

I read the same news reports with the same concern. However, if you check the Trees for the Future newsletters and Web site, you will see that almost all of the trees they plant are in the tropics. They are concentrating on places where trees will grow fast and provide benefits (like fruit) to the local natives quickly. This almost always means tropical regions.

I also have some questions about that report. As I understand it, trees are dark because they convert light to sugar and plant material, not heat. Did the scientists studying this matter really take that into account, or did they just look at the albido and figure they were producing heat. Also, trees reflect strongly in the infrared spectrum. It is hard to believe that they have a net heating effect. Also, there are trees and there are trees. Fast growing trees would absorb more CO2 than slower growing trees. One more thing: CO2 is acidifying the oceans, which causes them to release CO2 and add to the heating. Did the authors of that report consider this benefit of trees? Inquiring minds want to know! In short, I have considerable skepticism about this study. Planting trees still looks good to me.

tree planting doesn't offset carbon emissions
Submitted by jimurl on February 28, 2007 - 1:13pm.

I love trees. I think its great to plant them, especially in the equatorial regions. But planting trees doesn't offset carbon emissions.

Here's why: trees do grow and absorb carbon dioxide from the air. They tie that carbon up in the woody matter of the trees trunk, branches and leaves. But as soon as it dies and rots, the carbon dioxide is released back into the atmosphere. If you view the biosphere as a container, then adding carbon to that container from geologic sources is still a net addition of carbon. The carbon may slosh around in different forms, from atmospheric, to woody plant material, to dissolved in ocean waters; but it's still in the environment, rather than in the ground.

If we could plant enough trees so that there was actually a larger mass of wood on the planet, I suppose that would work to effectively tie up carbon, but we would have to keep the wood from decomposing. There has been literally billions of tons of carbon introduced to the biosphere in the last 250 years, and we would have to have a mass of wood equal to all of that.

Don't get me wrong- I think that there are a million good reasons to plant trees; but we can't plant our way out of global warming.

Jim