Amazon Forest Still A Climate Mystery

[Guest guest]

Amazon Forest Still A Climate Mystery

 

Scientists working to determine if it is a net carbon emitter

or 'sink'

 

http://www.msnbc.msn.com/id/22993043/

 

By Michael Astor

The Associated Press

updated 11:03 a.m. CT, Mon., Feb. 4, 2008

 

As the world tears up its rain forests at a rapid rate — 60 acres a

minute, the U.N. says — scientists in the Amazon are working to

understand the ominous feedback link between deforestation and a

warming world. This is the second of a three-part series.

 

MANAUS, Brazil - Julio Tota stood atop a 195-foot steel tower in the

heart of the Amazon rain forest, watching " rivers of air " flowing

over an unbroken green canopy that stretched as far as the eye could

see.

 

These billows of fog showed researcher Tota how greenhouse gases

emitted by decaying organic material on the forest floor don't rise

straight into the atmosphere, as scientists had supposed.

 

Instead, they hover and drift — confounding scientific efforts to

unlock the secrets of the world's largest remaining tropical

wilderness.

 

" What we've learned is, the Amazon rain forest is much more fragile

and much more complex than we had first imagined, " Tota said. " My

research is pretty specific. It's aimed at showing why all our

measurements are probably off. "

 

Tota is part of the Large Scale Biosphere-Atmosphere Experiment, a

decade-old endeavor involving hundreds of scientists, led by

Brazilians and with funding from NASA and the European Union. Their

open-air " laboratories " are 15 such observation posts spread over an

area of rain forest larger than Europe.

 

The project's goal is to make the best scientific arguments for why

this vast rain forest — along with other endangered forests in

Africa, southeast Asia and elsewhere — is essential to combating

global climate change.

 

But as the first phase of the $100 million experiment draws to a

close, its researchers acknowledge that the data have raised more

questions than answers.

 

Scientists can now say with certainty that the Amazon is neither the

lungs of the Earth, nor the planet's air conditioner. Paradoxically,

the forest's cooling vapors also trap heat, by reflecting it back

toward Earth in much the same way greenhouse gases do.

 

CO2 factor still unknown

 

But a key question remains unanswered: Does the Amazon work as a net

carbon " sink, " absorbing carbon dioxide, or is it adding more CO2 to

the atmosphere than it is subtracting, because of burning and other

deforestation that have claimed an average 8,000 square miles — an

area the size of Israel or New Jersey — each year of the past decade?

 

Scientists also can't predict every way in which continued

destruction of the Amazon — for timber, for cattle ranching, for

soybean farming — might affect global climate. But it will almost

certainly lead to drier conditions over a wide area, since ground

moisture taken up and evaporated through trees is recycled as

rainfall.

 

Some computer simulations suggest deforestation could cause droughts

as far afield as the U.S. grain belt, apparently because chain

reactions in the atmosphere would shift the Polar Jet Stream and the

precipitation it brings.

 

These questions take on new urgency as global warming's effects

become ever more apparent, and as forests fall at a nonstop pace. In

one sign of growing concern, Brazil's national leadership met in

emergency session on Jan. 24 to deal with a sudden surge in

deforestation after a three-year slowdown.

 

Tipping point near?

 

New studies suggest the Amazon may be approaching a tipping point, at

which the drier conditions caused by deforestation will reduce

rainfall enough to transform the humid tropical forest into a giant

savanna.

 

If preserving the 80 percent of the Amazon still standing would help

offset some greenhouse emissions, destroying it would almost

certainly accelerate global warming, by releasing perhaps 100 billion

tons of carbon into the atmosphere — equal to some 10 years' worth of

total global emissions.

 

" If you cut down all the tropical forests in the world you may

increase CO2 concentrations by 25 percent, " said Brazilian

climatologist Carlos Alberto Nobre. " It's important to keep the

forests intact because we are in a global warming crisis and it's

important not to reach a tipping point from which we can't come back. "

 

Deforestation — both the burning and rotting of wood in the Amazon —

already releases an estimated 400 million tons of carbon dioxide into

the atmosphere every year, accounting for up to 80 percent of

Brazil's greenhouse gases, boosting this country to sixth place or

higher among emitter nations.

 

By contrast, each acre of rain forest that remains intact takes

somewhere between 80 and 480 pounds of carbon out of the atmosphere

each year through the process of photosynthesis.

 

The uncertainty in that range hints at the unknowns still puzzling

researchers. In the next phase of the grand Amazon experiment, two

airplanes will measure emissions higher in the atmosphere, to try to

answer definitively whether the rain forest absorbs more carbon than

it produces.

 

Viewed from above, the Amazon appears to be an almost uniform carpet

of green, spreading over 2.7 million square miles and nine

countries. But in truth it's home to a wide range of ecological

systems and micro-climates.

 

That's why Biosphere-Atmosphere Experiment specialists are helping

design development models for each region, from managed logging to

fruit farming to the low-intensity harvesting of forest products such

as rubber, cocoa, fruits and ingredients for cosmetics and

pharmaceuticals.

 

" We're looking at what all this means for the prospect of

sustainability of the Amazon and how we can best inform decision-

makers about sustained productivity and land use, " Diane Wickland,

who manages NASA's Terrestrial Ecology Program, said from Washington.

 

The experiment has already yielded troubling conclusions, Wickland

said. Refined satellite surveillance, for example, finds that

selective logging affects about as much area as clear-cutting, adding

significantly to carbon dioxide emissions and casting doubt on

whether managed forestry can save the Amazon.

 

Brazilian physicist Paulo Artaxo, a veteran Amazon researcher, said

it's essential that Brazil, home to almost 70 percent of the rain

forest, sharply slow the destruction of its woodlands. " There is no

cheaper way to reduce emissions than by controlling deforestation, "

he said.

 

Scientists estimate it would cost about $1 billion a year in lost

income for Brazil to end the clearing of forest by loggers, ranchers

and farmers, largely giant soybean-growing conglomerates.

 

At the Bali conference, the world's nations decided to explore

possible plans for compensating rain-forest nations for rolling back

their rates of deforestation.

 

That money could come as " carbon credits, " in the trading system

under the Kyoto Protocol climate pact whereby industrial nations that

overshoot their greenhouse emissions quotas can get credit for

emissions reductions at power plants or other projects in the

developing world. By awarding credits to rain-forest states, richer

nations would now also be financing protection of carbon sinks.

 

The negotiations over such a complex global plan promise to be long

and difficult.

 

© 2008 The Associated Press.

 

URL: http://www.msnbc.msn.com/id/22993043/