AFP: Forests soak up third of fossil fuel emissions: study

[A-L-E-X]

http://www.google.co...5412e0c12be.a81

Forests soak up third of fossil fuel emissions: study

By Marlowe Hood (AFP) – 1 day ago

PARIS — Forests play a larger role in Earth's climate system than previously suspected for both the risks from deforestation and the potential gains from regrowth, a benchmark study released Thursday has shown.

The study, published in Science, provides the most accurate measure so far of the amount of greenhouse gases absorbed from the atmosphere by tropical, temperate and boreal forests, researchers said.

"This is the first complete and global evidence of the overwhelming role of forests in removing anthropogenic carbon dioxide," said co-author Josep Canadell, a scientist at CSIRO, Australia's national climate research centre in Canberra.

"If you were to stop deforestation tomorrow, the world's established and regrowing forests would remove half of fossil fuel emissions," he told AFP, describing the findings as both "incredible" and "unexpected".

Wooded areas across the planet soak up fully a third of the fossil fuels released into the atmosphere each year, some 2.4 billion tonnes of carbon, the study found.

At the same time, the ongoing and barely constrained destruction of forests -- mainly in the tropics -- for food, fuel and development was shown to emit 2.9 billion tonnes of carbon annually, more than a quarter of all emissions stemming from human activity.

Up to now, scientists have estimated that deforestation accounted for 12 to 20 percent of total greenhouse gas output.

The big surprise, said Canadell, was the huge capacity of tropical forests that have regenerated after logging or slash-and-burn land clearance to purge carbon dioxide from the atmosphere.

"We estimate that tropical forest regrowth is removing an average of 1.6 billion tonnes of carbon each year," he said in an e-mail exchange.

Adding up the new figures reveals that all the world's forests combined are a net "sink", or sponge, for 1.1 billion tonnes of carbon, the equivalent of 13 percent of all the coal, oil land gas burned across the planet annually.

"That's huge. These are 'savings' worth billions of euros a year if that quantity had to be paid out by current mitigation (CO2 reduction) strategies or the price of carbon in the European market," Canadell said.

The international team of climate scientists combined data -- covering the period 1990 through 2007 -- from forests inventories, climate models and satellites to construct a profile of the role global forests have played as regulators of the atmosphere.

In terms of climate change policy, the study has two critically important implications, said Canadell.

The fact that previous science underestimated both the capacity of woodlands to remove CO2, and the emissions caused by deforestation, means that "forests are even more at the forefront as a strategy to protect our climate", he said.

It also follows that forests should play a larger role in emerging carbon markets, he added.

"The amount of saving which are up for grabs is very large, certainly larger than what we thought," Canadell said.

The UN-backed scheme known as REDD -- Reduced Emissions from Deforestation and Degradation -- allots credit to tropical countries in Latin America, Asia and Africa that slow rates of forest destruction.

It also provides a mechanism for rich countries to offset their own carbon-reduction commitments by investing in that process.

Two decades was not enough to discern possible long-term trends due to year-on-year variability due to fluctuations in weather, insect attacks and other factors.

But the tropics did show a clear decline in the capacity to soak up CO2 due to a so-called "once-in-a-century" drought in Amazonia in 2005.

The region suffered an even worse drought in 2010, beyond the time frame of the study.

The breakdown over the last decade for CO2 removal was 1.8 billion tonnes each year for boreal forests at high latitudes, 2.9 billion for temperate forests, and 3.7 billion for tropical forests.

Once deforestation and regrowth are taken into account, however, tropical forests have been essentially carbon neutral.

[Clifford]

I am always a little suspicious about studies discussing the role of forests in the absorption of excess CO₂.

1000 years ago, were the Amazon and Congo in a "steady state"? Or were they absorbing more CO₂ than they were releasing?

Where does the "excess" Carbon go?

Why Now?

Certainly the timber industry removes millions or billions of tons of plant matter from the forests, which then regrows absorbing more CO₂. But, then the question is what happens to that plant matter that was removed from the forests? Your toilet paper quickly decomposes, and should be thought part of a carbon cycle rather than a carbon sink. Timber framing in a house might keep the wood out of the carbon cycle for the lifespan of the house. But, many houses will eventually be torn down and disposed of, again releasing the carbon dioxide into the environment.

[Hambone]

I own 6 heavily wooded acres. I guess I'm at least neutral.

Btw, I'm guessing lefty tree huggers are behind this story.

[tamarack]

I am always a little suspicious about studies discussing the role of forests in the absorption of excess CO₂.

1000 years ago, were the Amazon and Congo in a "steady state"? Or were they absorbing more CO₂ than they were releasing?

Where does the "excess" Carbon go?

Why Now?

Certainly the timber industry removes millions or billions of tons of plant matter from the forests, which then regrows absorbing more CO₂. But, then the question is what happens to that plant matter that was removed from the forests? Your toilet paper quickly decomposes, and should be thought part of a carbon cycle rather than a carbon sink. Timber framing in a house might keep the wood out of the carbon cycle for the lifespan of the house. But, many houses will eventually be torn down and disposed of, again releasing the carbon dioxide into the environment.

That TP in my septic tank may end up as landspread septage, fertilizing trees and weeds, though much of the carbon becomes CO2 during the breakdown processes. Landfilled paper/cardboard/etc takes years to decompose in the usual anaerobic conditions, and the larger landfills usually recapture methane for heating or other use - carbon ends up in the atmosphere but it's been put to work twice before it gets there. Life cycle analysis is extremely complex (how much gas does the skidder operator use while commuting to the logging site?), and some done for biomass show a number of decades before forest regrowth captures enough carbon to offset that turned to GHG in the harvest and combustion of the woody material. Still a shorter recapture period than for coal or petro-products.

[WeatherRusty]

I am always a little suspicious about studies discussing the role of forests in the absorption of excess CO₂.

1000 years ago, were the Amazon and Congo in a "steady state"? Or were they absorbing more CO₂ than they were releasing?

Where does the "excess" Carbon go?

Why Now?

Certainly the timber industry removes millions or billions of tons of plant matter from the forests, which then regrows absorbing more CO₂. But, then the question is what happens to that plant matter that was removed from the forests? Your toilet paper quickly decomposes, and should be thought part of a carbon cycle rather than a carbon sink. Timber framing in a house might keep the wood out of the carbon cycle for the lifespan of the house. But, many houses will eventually be torn down and disposed of, again releasing the carbon dioxide into the environment.

Taken as a whole, the carbon cycle prior to the industrial revolution for several thousands of years was in near equilibrium. As much carbon was being emitted by the system as was being naturally absorbed by the Earth's surface (land, seas, forests, soils, volcanoes etc.) so that atmospheric CO2 concentration held quite steady at about 280ppm. Now, with ongoing deforestation, the absorption is falling behind emissions so the carbon cycle has been thrown into imbalance. Like the article states, deforestation has been considered responsible for as much as 20% of the increase in atmospheric CO2 which now stands at over 390ppm.

As it is, nature is absorbing about 55% of our total emissions due to deforestation and fossil fuel burning. If forests are capable of absorbing as much as a third of the total CO2 overloading, then the seas, soils etc. are gobbling up the other two thirds. Our forests are very important as natural carbon sinks and have been as long as there have been forests.