Sacramento Bee

Researchers say cool earth temperatures linked to deforestation

LIVERMORE, Calif. (AP) -- Cooling earth temperatures between A.D. 1000 and 1900 have been linked to deforestation during that period, according to researchers.

Using computer simulations to test their theories, researchers at Lawrence Livermore Laboratory concluded that the regions on earth which cooled more over those 800 years were also the hardest hit by deforestation.

The researchers' discovery casts doubt on the debated notion that a great abundance of trees on earth can slow "global warming."

"It complicates life for people like me who are trying to predict climate change," said Philip Duffy, leader of the lab's group that conducted the study. "It's saying there's one more factor we have to account for when we want to predict future climates."

Duffy said the study also revealed that changes in land-use by humans also contributed to climate changes.

"The main way humans influence climate is by burning fossil fuels, which make greenhouse gasses," Duffy said.

Previous climate research focusing on "greenhouse gases" such as carbon dioxide and methane found those gasses trapped energy leaving the earth, thus warming the planet.

But the new findings suggest planting trees is not the most efficient way to cool the planet as they tend to capture massive quantities of heat.

The researchers collected data from various geological observations, including tree ring width and density studies.

Workers at the lab's Atmospheric Science Division suspected replacing forest cover with agriculture land-use contributed to dropping the earth's temperature up to 2 degrees Fahrenheit between A.D. 1000 and 1900.

-- Anonymous, April 24, 2001

Answers

I think if they would cut done on the size of cities and plant more trees it would solve more of their problems.

-- Anonymous, April 24, 2001