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Environment: Is the Amazon rainforest near a tipping point?

A NASA photo taken from the International Space Station shows sunlight glinting off the Amazon River.

A NASA photo taken from the International Space Station shows sunlight glinting off the Amazon River.

Drought the main driver of destructive fires

By Staff Report

FRISCO — Longer droughts, land-use changes and wildfires may  be pushing parts of the Amazon rainforest toward an ecological tipping point, a team of scientists said after analyzing the effects of fire in a series of study plots.

The changes may abruptly increase tree mortality and change vegetation over large areas, the researchers said, pointing out that current Amazon forest models don’t include the impacts of wildfires. As a result, projections of future forest health tend to underestimate the amount of tree death and overestimate overall forest health, said Dr. Michael Coe, of the Woods Hole Research Center. Continue reading

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Climate: Can forests heal themselves from drought?

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California’s redwood forests recycle ocean fog to create their own microclimate. bberwyn photo.

Amazon rainforest may be more resilient than previously believed

By Summit Voice

FRISCO — As one of the Earth’s big lungs, the fate of the Amazon rainforest in the face of global warming is a critical climate question. New research suggests that, with strong conservation measures in place, the rainforest may be more able to cope with dry conditions than projected by other studies.

Many climate models over-predict the water stress plants feel during the dry season because they don’t take into account the moisture that the forest itself can recycle in times of drought. In this study, published in the Journal of Climate, the researchers removed unrealistic water stress from their model and found that the moisture that is recycled by the forest is sufficient to reduce the intensity of drought conditions. Continue reading

Climate study shows that deforestation of the Amazon could dry out the western United States

Shifts in precipitation patterns would have big consequences for agriculture, forests and municipal water supplies

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Research suggests that deforestation will likely produce a weather cycle over the Amazon consisting of abnormally dry air in the sun-scorched northern Amazon around the equator weighted by wetter air in the cooler south (left). The Princeton-led researchers found that the Amazon pattern would be subject to meandering high-altitude winds known as Rossby waves that move east or west across the planet (center). The Rossby waves would move the dry end of the Amazon pattern directly over the western United States from December to February, while the pattern’s rainy portion would be over the Pacific Ocean south of Mexico (right). Image courtesy Princeton University.

By Summit Voice

FRISCO — Continued deforestation in the Amazon region could have significant impacts on the weather in North America, according to Princeton researchers, who used fine-grained climate models to simulate how precipitation patterns could shift in the future.

Their findings suggest that  total deforestation of the Amazon may significantly reduce rain and snowfall in the western United States — specifically, 20 percent less rain for the coastal Northwest and a 50 percent reduction in the Sierra Nevada snowpack, a crucial source of water for cities and farms in California.

“The big point is that Amazon deforestation will not only affect the Amazon — it will not be contained. It will hit the atmosphere and the atmosphere will carry those responses,” said lead author David Medvigy, an assistant professor of geosciences at Princeton. Continue reading

Climate: Southern Amazon at risk of drying out

New study says IPCC projections are too conservative

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Studies show that fires are on the increase in the Amazon. Visit this NASA Earth Observatory web page for more information.

By Summit Voice

FRISCO — In a classic case of climate disruption, research shows that the dry season in southern Amazonia has lengthened by about one week per decade since 1979. Parts of the region may not be able to support rainforest vegetation much longer. A big forest die-back could trigger the release of large volumes of the greenhouse gas carbon dioxide into the atmosphere, a team of scientists warned this week.

The changes could disrupt plant and animal communities in one of the regions of highest biodiversity in the world, said University of Texas professor Rong Fu, who led the team of scientists. Continue reading

Conservation planning must consider global warming

More than two-thirds of the species at risk from global warming haven’t been targeted for conservation

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By Summit Voice

FRISCO —Global warming hasn’t been a key consideration in long-term conservation planning, which means that most species at greatest risk from climate change are not currently prioritized for conservation, according to an International Union for Conservation of Nature study that has introduced a pioneering method to assess the vulnerability of species to climate change.

The paper, published in the journal PLOS ONE, is one of the biggest studies of its kind, assessing all of the world’s birds, amphibians and corals. It draws on the work of more than 100 scientists over a period of five years, including Wits PhD student and leader of the study, Wendy Foden. Download the study here. Continue reading

Global warming hits Amazon rainforest

More frequent droughts take a toll on forest canopy

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A megadrought starting in 2005 resulted in widespread damaged to the canopy of the Amazon rainforest. Photo courtesy NASA/JPL-Caltech.

By Summit Voice

FRISCO — With climate scientists warning that droughts are likely to become more frequent and severe as global temperatures continue to climb, a recent study led by NASA scientists shows what that could mean for the Amazon rainforest.

After analyzing more than 10 years worth of satellite data collected from over the Amazon region, the researchers said rainforest damage first observed during the start of a megadrought in 2005 persisted the next several years, even as rainfall gradually rose back to average levels. But another dry period that started in 2010 may exacerbate the impacts, suggesting that the Amazon rainforests may be showing the first signs of potential large-scale degradation due to climate change. Continue reading

Chevron ordered to pay huge fine for Ecuador oil pollution

Chevron has been ordered to pay $9 billion in damages for oil pollution in Ecuador's Amazon rainforest.

18-year court battle decided in favor of indigenous people; oil company vows to appeal the ruling

By Summit Voice

SUMMIT COUNTY — In a potentially precedent-setting ruling in the arena of environmental law, an Ecuadorian court this week ruled that Chevron must pay $9 billion in damages for oil pollution in remote Amazon rainforests.

The case has been under litigation for 18 years and dates back to oil exploration activities by Texaco in the 1970s, before the company was acquired by Chevron.

Environmental advocates said it’s the first time indigenous people have successfully sued a big multi-national corporation for environmental wrong-doing.

Chevron officials said they won’t pay the fines and will appeal the ruling. Continue reading

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