Post date: Mar 04, 2013 1:50:19 PM
New research shows that warming temperatures are melting Andean glaciers at unprecedented rates, raising fears of water shortages by the middle of the century.
Using the latest satellite data, scientists say glaciers along the Cordillera Real range are losing about one metre of ice thickness per year because of climate change.
HUAYNA POTOSI, BOLIVIA (REUTERS) - Climate change has diminished Andean glaciers by between 30 and 50 percent since the 1970s and could cause some of them to disappear completely in coming years, according to the most comprehensive review of Andean ice loss conducted so far.
Andean glaciers, a vital source of fresh water for tens of millions of South Americans, are retreating at their fastest rates in more than 300 years, according to the study published earlier this year in the journal The Cryosphere.Edson Ramirez, a glacier researcher at Bolivia's Universidad Mayor de San Andres, says the loss of Andean glaciers marks a major blow to the world's largest concentration of tropical glaciers.
"We now know that from the '80s to the present, we have lost 43 percent of the entire surface area of the Cordillera Real," said Ramirez, who co-authored the study.
The findings are underpinned by satellite data transformed into high resolution three-dimensional images of the mountains. Ramirez says they clearly show a loss of glacial cover compared to images taken in the past.
Bolivia contains about 20 percent of the world's tropical glaciers. Peru is home to about 70 percent, while Ecuador holds about 4 percent.
Ramirez and other scientists are working on a project to map the changes in Andean glaciers in more detail than ever before, although he says the disappearances inBolivia's Cordillera Real mountain range began decades ago.
Yuko Nakamura, a project coordinator at Japan's International Cooperation Agency, is also monitoring the disappearance of glaciers in the region. She comes regularly to help monitor weather stations dotted around the mountains. She says she notices the differences year by year.
"In the last 10 years of study, I have verified in the field an accelerated retreat of the glaciers in this part of the world," she said.
The study included data on about half of all Andean glaciers in South America. It blames the ice loss on an average temperature spike of 0.7 degree Celsius (1.26 degrees Fahrenheit) over the past 70 years.
"The glaciers as such are excellent indicators of the change of the climate, therefore these drastic changes that we are observing are clearly showing us that there are already significant changes in our ecosystems and therefore we need to begin to prepare ourselves and take action to adapt in front of what is provoking these changes in climate," said Wilson Suarez, a glaciologist at Peru's National Service of Meteorology and Hydrology (SENAMHI).
Suarez, who co-authored the January study, says many glaciers in Peru are also vulnerable.
"What we are seeing is that all the glaciers that have a maximum height of 5,100 metres have actually disappeared. And we now expect that all those between 5,300 and 5,400 (metres) will disappear in the next 30 or 40 years. For example, the snow cap of Huaytapallana, at a height of about 5,400 metres, the studies show us it could disappear between 2027 and 2035."
The Chacaltaya glacier in the Bolivian Andes, once a ski resort, has already disappeared completely, according to some scientists.
Lower glaciers, too, are also facing threats. The Cryosphere study warns that future warming could totally wipe out the smaller glaciers found at lower altitudes that store and release fresh water for downstream communities.
Suarez says Andean communities, like one in Peru's Cordillera Blanca mountain range, are already having to adapt. The report says that for those mountains, "an increase of more than 4 C. at elevations above 4000m is projected for the 21st century." It says that "such a temperature change could lead to a major reduction in glacial coverage and even to the complete disappearance of small glaciers."
For local communities, Suarez says such a temperature spike would be disastrous. Irrigation projects to provide water from the Cordillera Blanca, for villages spread over about 70,000 hectares, will be for naught if the glaciers disappear he says. Cities like Huancayo, with a population of about 400,000 people will simply disappear.
Ronald Woodman, president of Peru's Geophysical Institute agrees.
"Many of the coastal rivers depend, especially in the dry season, on the water that comes from the melting of the glaciers and these will disappear. The flow of water in the dry season from the rivers is going to be much lower, if not zero in many of the valleys inPeru," he said. "This is going to have an impact on agriculture and also on the generation of electrical power, because we use the waters not only to irrigate, but also as a source of a good portion of the energy that we consume."
Woodman says it may be too late to curb the effects of climate change in that part of the world, so measures to adapt must be explored.
"What can we do? We can adapt. If we know it's coming, we can think about what methods to take so it won't affect us. Minimize, mitigate the effects of climate change. Adaptation is the word, not abating the change," he said.