Strangely, the loss of forests may actually be cooling the planet

An intriguing study from Yale University shows that large-scale forest losses over the last 150 years – largely through the conversion of forests to cropland – produced a net global cooling effect of about 0.1 degrees Celsius. During the same period, the global climate warmed by about 0.6 degrees Celsius, mostly due to increases in fossil fuel carbon dioxide emissions.

Detailing her work in the journal Nature Climate Change, Yale’s Nadine Unger calculated that a 30-percent decline in biogenic volatile organic compound (BVOC) emissions between 1850 and 2000 was responsible for the cooling effect.

“Land cover changes caused by humans since the industrial and agricultural revolutions have removed natural forests and grasslands and replaced them with croplands,” explained Unger. “And croplands are not strong emitters of these BVOCs – often they don’t emit any BVOCs.”

BVOCs emitted from forested areas are players in both the formation and distribution of other climate pollutants, such as ozone, methane, and aerosol particles. Not all of these compounds affect atmospheric chemistry in the same way. Aerosols, for example, contribute to global cooling since they generally reflect solar radiation back into space. Therefore, a 50 percent reduction in forest aerosols has actually spurred greater warming since the pre-industrial era. However, reductions in the potent greenhouse gases methane and ozone have helped deliver a net cooling effect.

Unger says the climate impact of declining BVOC emissions is on the same magnitude as two other consequences of deforestation: carbon storage and the albedo effect. The lost carbon storage capacity caused by forest conversion has exacerbated global warming. Meanwhile, the disappearance of dark-colored forests has also helped offset temperature increases through the albedo effect (the amount of light and heat reflected by the surface of the planet).

She believes the combined effects of reduced BVOC emissions and increased albedo may have entirely offset the warming caused by the loss of forest-based carbon storage capacity.

She is quick to stress that the findings do not suggest that increased forest loss provides climate change benefits, but rather underscore the complexity of climate change and the multitude of factors involved. “These emissions are often ignored in climate modeling because they are perceived as a natural part of the Earth system,” explained Unger. “So they don’t get as much attention as human-generated emissions, such as fossil fuels. But if we change how much forest cover exists, then there is a human influence on these emissions. The sensitivity of the global climate system to BVOC emissions suggests the importance of establishing a global-scale long-term monitoring program.”

Related:
Discuss this article in our forum
Food security emerging as major climate change issue
Rising CO2 causing nutritional content of crops to fall
CO2 not to blame for global warming, claims new study that argues global cooling has already begun
Volcanoes keeping a lid on global warming

Source: Yale School of Forestry & Environmental Studies

, , ,

Comments are closed.

United States Forest Service Challenge Coin  picture

United States Forest Service Challenge Coin

$14.44



US Forest Service 1960's Patch.Die cut 2

US Forest Service 1960's Patch.Die cut 2" x 2" sticker Made for Coleman lanterns

$4.00



Vintage Smokey the Bear Forest Fire Prevention Poster - Woodland Flowers 1980s picture

Vintage Smokey the Bear Forest Fire Prevention Poster - Woodland Flowers 1980s

$18.99



Antique vintage 1930s Scene In Action Forest Fire With Cabin Motion Lamp - AS-IS picture

Antique vintage 1930s Scene In Action Forest Fire With Cabin Motion Lamp - AS-IS

$95.00



Fox Forest Wild animals Beast porcelain figurine realistic Souvenirs handmade picture

Fox Forest Wild animals Beast porcelain figurine realistic Souvenirs handmade

$59.00



Vtg Plastic CHRISTMAS TABLECLOTH Christmas Tree Rabbits Deer Forest Animals Snow picture

Vtg Plastic CHRISTMAS TABLECLOTH Christmas Tree Rabbits Deer Forest Animals Snow

$10.99



BAMBOO BEAR #25121 Just the Right Shoe Raine Forest COA Protect Wildlife picture

BAMBOO BEAR #25121 Just the Right Shoe Raine Forest COA Protect Wildlife

$12.00



Bunny Rabbit Bookends Heavy Cast Stained Resin Woodland Brown Tone picture

Bunny Rabbit Bookends Heavy Cast Stained Resin Woodland Brown Tone

$34.99



PULASKI AXE-U.S. FOREST SERVICE picture

PULASKI AXE-U.S. FOREST SERVICE

$74.99



8

8" Inch Green Forest Fairy with Mushrooms Statue Figurine Figure Fantasy Magical

$34.33



Powered by WordPress. Designed by WooThemes