Solutions to climate change and global warming

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.

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