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Posts Tagged ‘Rain Forest’

Drought Causes Amazon Rainforest Trees to ‘Inhale’ Less Carbon from the Atmosphere

March 6, 2015 Comments off

scienceworldreport.com

Catherine GriffinAmazon Rainforest
For the first time ever, scientists have discovered direct evidence of the rate at which individual trees in the Amazon rainforest “inhale” carbon from the atmosphere during a severe drought. (Photo : Flickr/Mark Goble)

For the first time ever, scientists have discovered direct evidence of the rate at which individual trees in the Amazon rainforest “inhale” carbon from the atmosphere during a severe drought. The findings could be huge when it comes to calculating how much these forests contribute to carbon capture and storage in the future.

Scientists have long suspected that drought influences how much carbon trees manage to capture and store. The extent of that influence has long remained a mystery-until now. Scientists measured the growth and photosynthesis rates of trees at 13 rainforest plots across Brazil, Peru and Bolivia, comparing plots that were affected by the strong drought of 2010 with unaffected plots.

Each of the plots contained between 400 to 500 trees. In addition, the rainforest plots that were chosen were

Read more…

Categories: Rainforest Tags: , , , , ,

Cutting Down Rainforests Also Cuts Down on Rainfall

September 6, 2012 2 comments

cientificamerican

As the Amazon rainforest disappears, rainfall falters over a much wider area

By Lauren Morello and ClimateWire

Slash and burn agriculture in the Amazon RAIN MAKER: Cutting down trees in the Amazon rainforest also reduces rainfall over the region. Image: flickr/Threat to Democracy

When Amazon rainforest disappears, so does Amazon rain.

That’s the conclusion of new research that shows deforestation can significantly reduce tropical rainfall far from the area where trees have been cut down.

That’s because air passing over forests picks up moisture given off by trees and plants, fueling rains. When those trees disappear, so does some of that rain.

“What we found was this really strong impact — air that traveled over a lot of forest brought a lot more rain than air that didn’t travel over very much forest,” said lead author Dominick Spracklen of the University of Leeds.

His research, published yesterday in the journal Nature, helps reconcile a situation that has puzzled scientists.

Climate models project that Amazon deforestation would reduce rainfall regionally. But limited observations show that rainfall in deforested areas is higher than in areas where the rainforest is still intact.

(Scientists believe that when trees are cut down, the bare surfaces left behind absorb more Read more…

Categories: Brazil, Climate Change Tags: , , ,

Rainforest in Transition: Is the Amazon Transforming before Our Eyes?

January 20, 2012 1 comment

scientificamerican.com

amazon-pasture RAINFOREST TO PASTURE: Deforestation, among other human impacts such as climate change, are having a rainforest-wide impact on the Amazon. Image: Courtesy of Compton Tucker, NASA GSFC

The Amazon rainforest is in flux, thanks to agricultural expansion and climate change. In other words, humans have “become important agents of disturbance in the Amazon Basin,” as an international consortium of scientists wrote in a review of the state of the science on the world’s largest rainforest published in Nature on January 19. (Scientific American is part of Nature Publishing Group.) The dry season is growing longer in areas where humans have been clearing the trees—as has water discharge from Amazon River tributaries in those regions. Multiyear and more frequent severe droughts, like those in 2005 and 2010, are killing trees that humans don’t cut down as well as increasing the risks of more common fires (both man-made and otherwise).

The trees are also growing fast—faster than expected for a “mature” rainforest—according to a network of measurements.

The exact cause or causes of this accelerated growth—which means the Amazon’s 5 million square kilometers of trees are now Read more…

Categories: Brazil Tags: , ,

Deforestation in Brazil’s Amazon up 15 percent

August 18, 2011 Comments off

rawstory

BRASILIA — Deforestation in Brazil’s Amazon increased by 15 percent during the past 12 months, the National Institute for Space Research (INPE) said.

From July 2010 to July 2011 the vast South American rainforest lost 2,654 square kilometers (1,649 square miles) of vegetation in the states of Mato Grosso and Para, according to a preliminary analysis of satellite photos.

The year before, 2,295 square kilometers (1,426 square miles) were destroyed over that time period.

This July, 225 square kilometers (139 square miles) were lost to deforestation, though this was significantly less than the 485 square kilometers (301 square miles) destroyed in July 2010.

In April 477 square kilometers (296 square miles) were destroyed, with Read more…

Categories: Brazil Tags: ,

Drought In Amazon Could Lead To Accelerated Global Warming

March 30, 2011 Comments off

ibtimes.com

A new study reveals a drought last year in the Amazon basin caused the forest to lose significant levels of vegetation, which in turn could accelerate the pace of global warming.

The study, conducted by an international team of scientists and funded by NASA, uses specific satellite imaging data provided by the agency to draw its conclusions. The Moderate Resolution Imaging Spectroradiometer (MODIS) and Tropical Rainfall Measuring Mission (TRMM) satellites provided more than a decade’s worth of data for scientists who studied the de-vegetation of the Amazon rainforest.

(Photo: NASA/BU) NASA satellite sensors, such as MODIS, showed an average pattern of greenness of vegetation on South America: Amazon forests which have very high leaf area are shown in red and purple colors, the adjacent cerrado (savannas) which have lower leaf area are shown in shades of green, and the coastal deserts are shown in yellow colors.

 

The scientists say changing climates with warmer temperatures and altered rainfall could lead to the rainforests turning into grasslands or woody savannas. This causes carbon stored in the rotting wood to be released into the atmosphere, which would add to the greenhouse gases present.

“The greenness levels of Amazonian vegetation — a measure of its health — decreased dramatically over an area more than three and one-half times the size of Texas and did not recover to normal levels, even after the drought ended in late October 2010,” Liang Xu, the study’s lead author from Boston University, said in a statement.

“The MODIS vegetation greenness data suggest a more widespread, severe and long-lasting impact to Amazonian vegetation than Read more…

Categories: Droughts, Global warming, South America Tags: , , , , , , , , , , ,

CO2 Fears After Amazon Rainforest Droughts

February 6, 2011 1 comment

Two severe Amazon droughts have sparked fears that the rainforest’s ability to absorb carbon emissions is being diminished – and, worse still, it may soon release almost as much CO2 as the US.

A rare drought in 2005 – billed as a once-in-a-hundred-years event – was then followed by another drought in 2010 that may have been even worse, according to a study by a team of British and Brazilians scientists in the journal Science.

With a huge number of trees dying as a result of the droughts, the scientists predict that the Amazon will not be able to absorb as much carbon dioxide from the atmosphere as usual in future.

This would remove an important global buffer against pollution.

Even worse, rotting trees may release into the atmosphere as much as five billion tons of C02 in the coming years.

That would be almost as much as the 5.4 billion tons emitted from fossil fuel use by the US in 2009.

Based on the impact of the dry spell on tree deaths in 2005, the team projected that Read more…

Categories: Droughts, South America Tags: , , , , , , ,