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Unprecedented glacier melting in the Andes blamed on climate change
Glaciers in the tropical Andes have been retreating at increasing rate since the 1970s, scientists write in the most comprehensive review to date of Andean glacier observations. The researchers blame the melting on rising temperatures as the region has warmed about 0.7°C over the past 50 years (1950-1994). This unprecedented retreat could affect water supply to Andean populations in the near future. These conclusions are published today in The Cryosphere, an Open Access journal of the European Geosciences Union (EGU).
Climate Record Suggesting Severe Tropical Droughts as Northern Temperatures Rise
 Laguna Pumacocha in the Peruvian Andes. |
A 2,300-year climate record Universityof Pittsburgh researchers recovered from an Andes Mountains lake reveals that as temperatures in the Northern Hemisphere rise, the planet’s densely populated tropical regions will most likely experience severe water shortages as the crucial summer monsoons become drier. The Pitt team found that equatorial regions of South America already are receiving less rainfall than at any point in the past millennium.
The researchers report in the Proceedings of the National Academy of Sciences (PNAS) that a nearly 6-foot-long sediment core from Laguna Pumacocha in Peru contains the most detailed geochemical record of tropical climate fluctuations yet uncovered. The core shows pronounced dry and wet phases of the South American summer monsoons and corresponds with existing geological data of precipitation changes in the surrounding regions.
Paired with these sources, the sediment record illustrated that rainfall during the South American summer monsoon has dropped sharply since 1900-exhibiting the greatest shift in precipitation since around Read more…
Deaths and thousands infected with dengue in Paraguay and Bolivia
“We have 18 dengue deaths confirmed in Paraguay and 2.500 infected of which 1.300 are hospitalized” said Ivan Allende head of the Sanitary Vigilance Department in Asuncion. He also called on the population to immediately report to a clinic or hospital on suspicion of having contracted the disease, which again reappeared with extreme force in late December with the rainy season.
“In previous years we never had so many people hospitalized” added Allende who indicated that only zero temperatures can help eliminate the mosquito larvae. “Until then we must insist people must collaborate watching out for stagnant water in bottles, old tyres, and flower pots and obviously in toilets and sewage”.
In Bolivia the death toll has climbed to 20 and the number of infected totals 1,670. Read more…
Drought In Amazon Could Lead To Accelerated Global Warming
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…
CO2 Fears After Amazon Rainforest Droughts
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…
Scientists warn of new Chilean quake
Rescue workers search for victims and survivors after an apartment complex collapsed during an 8.8-magnitude earthquake in Concepcion on February 27, 2010. Scientists say there is a high risk of a new earthquake in an area of Chile's Pacific coast which was hit by a massive quake and tsunamis last year.
Nearly 500 people were killed when an 8.8-magnitude earthquake struck off the coast of central Chile triggering a local tsunami in February 2010.
According to the report published in the journal Nature Geoscience, the previous quake had only partly broken stresses, deep in the Earth’s crust in the Chilean city of Concepcion, that have been building up since an 1835 quake witnessed by British naturalist Charles Darwin.
Darwin documented the 1835 earthquake during a five-year voyage.
“We conclude that increased stress on the unbroken patch may in turn have increased the probability of another major to great earthquake there in the near future,” the report read.
Chile’s February quake was the most powerful since the one in 2004 which caused a devastating tsunami in the Indian Ocean.
“It’s impossible to predict exactly when a new quake might happen,” Stefano Lorito of Italy’s Istituto Nazionale di Geofisica e Vulcanologia told Reuters.
Scientists examined data from tsunamis, satellites and other sources to calculate the Read more…
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