Saving the trees could slow climate change, new research shows. Each year, nearly 33 million acres of forestland around the world is cut down, according to the Food and Agriculture Organization of the United Nations. Tropical felling alone contributes 1.5 billion metric tons of carbon—some 20 percent of all man-made greenhouse gas (GHG) emissions—to the atmosphere annually. If such losses were cut in half, it could save 500 million metric tons of carbon annually and contribute 12 percent of the total reductions in GHG emissions required to avoid unpleasant global warming, researchers recently reported in Science.

Forest depletion ultimately contributes more GHG emissions than all the cars and trucks in use worldwide, says Werner Kurz, a forest ecologist with Natural Resources Canada, who was not involved with the study. "What we are doing in these tropical forests is really a massive problem."

Changes in forest management and agricultural practices could significantly reduce the threat of global warming much more quickly than can technological solutions such as carbon capture and storage (CCS) from coal-fired power plants, according to experts. "We don't know how to do CCS. These are things we could do today," says Bruce McCarl, an agricultural economist at Texas A&M University in College Station. "They are a bridge to the future."

Among proposed changes: more widespread adoption of so-called no-till farming, a practice that involves leaving unharvested crop stalks and other plant matter behind in the field undisturbed by plows and other soil-agitating instruments. "Anything that reduces soil disturbance increases carbon storage," McCarl notes.

Basically, the carbon stored inside the remains sinks into the soil instead of being stirred up and into the atmosphere when the soil is prepared for planting using conventional means. Such no-till farming provides a double benefit for farmers: improved soils and reduced fuel use, because it negates the need to harvest the stalks with tractors and other equipment (although it can lead to short-term reductions in crop yields) says Chuck Rice, a soil scientist at Kansas State University in Manhattan, Kan.

The opportunity to pour carbon back into the soil exists because farming over the past century has depleted its levels of organic carbon, Rice notes. But, as with water, the soil can only hold so much carbon before it is saturated. "Sequestration could be provided for the next 30 to 50 years," before the soil will reach its limit and other actions will be needed, he says.

Growing crops for fuel—known as biofuels—represents another potential way of cutting GHGs by replacing fossil fuels (biofuels created underground by nature over millions of years). "Biofuel production also shows promise for directly offsetting some reliance on fossil fuels," says Stephen Ogle, an ecosystem research scientist at Colorado State University in Fort Collins. "This represents a direct reduction in emissions from the current trends, because dedicated energy crops will reassimilate some of the carbon dioxide emitted by energy use."

Such changes, however, are not without peril. They could lead to higher food prices as well as to converting marginal lands back into crop production, which would, in turn, lead to GHG emissions. Further, pursuing cellulosic ethanol (a biofuel brewed from stalks and other leftover plant material) could eliminate the same remnants—and, therefore, their carbon storage potential—that no-till practices would otherwise sequester, Rice adds, noting that the risks and benefits of any solutions must be carefully weighed.

There are some radical (and less likely) solutions as well, given that more than half of U.S. acreage is used to produce animal feed. "If we really want to solve the world greenhouse gas problem, we will all become vegetarians," McCarl says, pointing out that it takes seven pounds of feed to raise a pound of beef, 1.4 pounds for chickens and three pounds of feed per pound of hog. "If everyone was a vegetarian," he says, "then you could farm a lot less acreage."

7 Comments

1. 1. David M. Clemen 02:48 PM 3/22/08

   The author states that"...Forest management is the linchpin of any effort to combat climate change...". I recall in the 1970's when environmentalists stopped all forest service thinning/forest management programs because they called it "logging" the forests. Forest management was equated with clearcutting by the environmentalists; and, to this date, the U.S. forest service does not have a "thinning" program.
   This has resulted in forest fires that now burn over 6 million acres a year (for the last five years) rather than the 3 million per year that were burned in the 1980' & 90's. Nowhere do we hear outcries against this large source of CO2 production, and esp. not from the environmentalists who stopped the forest management programs of the 1970's.
   Why not get really serious about GHG; and institute forest managment again? Three million acres of "burned" trees is a huge amount of greenhouse gasses.

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2. 2. bfreewithrp 04:45 PM 3/29/08

   I must enter my opinion on this subject here. Here is an article I wrote recently.
   In the News.Global Warming, truth or consequences. Please pass
   on to your friends. Thanks
   
   http://www.quazen.com/News/Opinions/Al-Gores-Decree-on-Global-Warming-is-Not-Our-Only-Crisis.51904
   Al Gore's Decree on Global Warming is Not Our Only Crisis
   
   http://www.quazen.com/Science/Environment/Our-Energy-Conservation-Dilemma.32660
   Our Energy Conservation Dilemma

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3. 3. joelprestonsmith 01:25 PM 9/13/08

   The author states "Tropical felling alone contributes 1.5 billion metric tons of carbon." Does he mean that the ACT of felling trees contributes 1.5 billion metric tons (perhaps through CO2 releases associated with operating heavy equipment), or does he mean that tropical felling RESULTS in (the passive subsequent release of) 1.5 billion tons?
   
   Thanks (from a fellow journalist, trying to comprehend the mechanisms of CO2 production and cycling).
   
   Joel

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4. 4. rayq 08:35 PM 3/25/09

   You should take a look at this. These guys seem to have found an answer.
   <a href="http://southern-cross.webs.com/apps/blog/entries/show/560766-the-y3000-plan-introduction
   ">Global Warming solutions</a>

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5. 5. Eclipse 06:04 PM 12/1/09

   I keep saying it, BIOCHAR! Imagine agriwaste and forestry waste being turned into soil enriching (and Carbon sequestering) biochar, fuel for the rural community), and food. Excellent! Google biochar and read up on it for yourselves, it truly is a major new 'wedge' in our battle against Co2, along with better town planning, better public transport, electrifying transport (because peak oil is coming anyway) and renewable energy. We can do this!

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6. 6. Eclipse in reply to Lrqausa1 01:57 AM 4/16/10

   Umm, isn't that just spam Lq?

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7. 7. iconzerv in reply to David M. Clemen 12:43 PM 10/3/10

   fires are the natural regeneration method of many forests (like red pine stands). it paves the way for successional vegetative sequences and promotes heterogeneity which in turn enhances biodiversity across a lanscape. fires can also regulate things like insect outbreaks. Its not so black and white David.

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