New Study: Reforesting May Not be the Answer
Longtime readers of this blog may remember a post from mid-December about trees, and the importance of their physical location in terms of whether they slowed global warming or enhanced it. I had a little feeling of deja vu this morning when I opened an article published yesterday at Scientific American.com. This new study, published in Proceedings of the National Academy of Sciences, found similar results.
Forests in tropical regions serve as carbon sinks, forests in the mid-latitudes are nearly carbon-neutral, and boreal forests, the zone pictured here in dark green in an image from NASA, actually contribute to global warming.
How is that possible? It's mostly due to albedo, that measure of the reflectivity of the Earth's surface. Tropical trees, growing in very wet soil, produce by a process called evotranspiration a layer of clouds which reflect sunlight. That reduction in solar input combined with the carbon storage in the trees has an overall net cooling effect on the globe. Compare that to the boreal region - primarily coniferous trees in an area covered by snow for a significant portion of the year. The soil is dry, so the trees produce little moisture and few clouds via evotranspiration, and the trees absorb more energy than snow-covered land would reflect.
The study was done using a model which captured all three of these forest characteristics - carbon storage, reflectivity and evotranspiration. In the framework of the model, researchers were able to see what would happen if the entire globe was deforested. The research has value because it shows where reforestation has the most value in mitigating greenhouse gases and reducing global warming.
Trees of course, have importance far beyond their role as carbon sinks. Sustaining forests helps to sustain the world's biodiversity. Making decisions on forestry based solely on global warming isn't good policy for the world.
Comments (12)
OK, let's shoot little flecks of metallic stuff in the clouds to reflect sunlight! Even nature is ruining this world!!!
Posted by Judy | April 11, 2007 11:42 AM
Count Newt Gingrich in as one of the growing number of conservative politicians who agree with the scientific consensus on global warming. See the link.
http://www.washingtonpost.com/wp-dyn/content/article/2007/04/10/AR2007041001457.html?nav=hcmodule
The debate is rapidly shifting to figuring out solutions to AGW. I know the deniers would like to forever drag out this debate on whether AGW is real, but unless real-world data and observation starts reversing itself, it's time human ingenuity works on solutions.
Posted by Mark | April 11, 2007 11:45 AM
What steps can I take to increase my carbon footprint? I am sitting here in Grand Rapids Michigan and it is pretty much a blizzard outside my window right now. That's right it is April 11 and we are expecting around 6" of snow today. So I would like to increase my carbon footprint and speed up the global warming process. I mean I can't wait around 100 years to see if the predictions of doom by the AGW alarmists will come true, I want warmer weather now and not the measely one or two degrees that they are predicting.
Posted by andy | April 11, 2007 12:50 PM
Mark - Thanks for the link. I had another link to the same subject matter waiting in my inbox, and I'll be using both of those this afternoon.
Posted by Laura Hannon | April 11, 2007 1:39 PM
I say let the pines continue to flourish(& plant even more) if it can help warm the frozen north where I live & keep our heating bills for gas/oil use down(and thus lowering the AGW ratio that everyone's worried about AND protecting the northern wildlife that everyone's also worried about, AND providing shade for the summer)....see how mother nature works? Maybe we can eventually get more of those pines north of 60N latitude to stop these damn April cold fronts we've been getting & bring normal spring temps back to the US/Canada(not to mention provide better for wildlife up there)....
Posted by Anonymous | April 11, 2007 3:51 PM
Gingrich is trying to get elected president. He has to up his numbers among liberals...enough said.
Posted by Ram K. | April 11, 2007 10:42 PM
Okay, now we're in even more trouble if the trees are contributing to GW. So now what do we do? Do we make the people that are contributing the most chop down those trees, and once they are done take them out back and shoot 'em?? Can people finally realize now that maybe, just maybe, the earth is doing this naturally, and there is nothing we can do to stop it? We could chop down the trees, but don't we need those to breathe? While we can take care of the resources that have given to us, the earth is going to continue to get warmer. I wouldn't be a bit surprised that many years down the road we see the earth hit its peak warmth and start to cool off. Then there will be mass panic again because the world is cooling. Weren't we all supposed to have our flying cars and living in space by now anyway?? Where's are flying cars?
Posted by Julie | April 12, 2007 7:59 AM
Julie, what is "natural" about 25 trillion tons of CO2, which took hundreds of millions of years for the Earth to bury into the ground, being unearthed and emitted into the atmosphere in a span of 100 years?
Let's hear your explanation.
Posted by Mark | April 12, 2007 11:48 AM
Andy:
I'll throw an extra tire on the fire for you tonight when I get home. Maybe, just maybe, I will also drive my SUV around the block a couple of extra times too. Down here in Ohio, I lost a lot of plants to the freeze.
Mark:
That's right, build the entire case for AGW solely upon nothing more than the bandwagon principle. That's definitely sound scientific process. I wonder, if the data does reverse itself, can we go back to stripmining and big V8's with no mufflers?
Posted by Darren | April 12, 2007 12:08 PM
I wonder if we can generate carbon credits for CUTTING down trees in the boreal forest. The loggers will love this.
Posted by herschel | April 12, 2007 12:55 PM
Mark,
Because 90% of it is still in the ground...duh!!
Try again, your numbers change like the weather....no pun intended.
BTW, you must be in therapy for siding with Gingrich on ANYTHING. All of a sudden he has credibility??? Your fingers must have fallen off after you typed that message.
One more pun: YOU are a fair-weather friend aren't you....tee hee.
Posted by Dave | April 13, 2007 1:31 PM
I knew GW wasn't America's fault. Brazil is to blame!
Posted by SM | April 16, 2007 3:42 PM