Mountain glaciers are melting faster-a study

Ice caps on planet’s Mountain glaciers are melting faster as compared to the time 5,000 years because of an unprecedented period of global warming, a study has discovered.

The researchers, who have studied ice cores taken from mountains ranging from Andes in South America to Himalayas in Asia, have revealed that climate change is leading to destruction of the tropical glaciers.

The research team had dug out the layers of glaciers put down by snow thousands of years ago. The air bubbles caught in those ice cores were analyzed to learn about the atmosphere at the time. Other clues are in the form of sediment, insects and pollen.

The Scientists, headed by Lonnie Thompson of Ohio State University, have warned that human activities over the past 100 years may have nudged the global climate beyond a critical threshold which could see most of the highest ice caps disappearing within the near future, completely.

In an article released on Monday in the Proceedings of the National Academy of Sciences, they said that the Melting glaciers in South America and Asia not only contribute to rising sea levels, they are also vital sources of freshwater for many millions of people who live within their range at lower altitudes.

The researchers also said that Earth's climate is undergoing abrupt changes, ending a cooler phase that started some 5,200 years ago, coinciding with the start of the cities, the beginning of calendars and the biblical great flood.

Thompson, along with his fellow teammates, has come forth with three lines of evidence pointing to a dramatic melting of glaciers in both the Andes and the Himalayas that are a change in the chemical isotopes of the ice cores, the widespread retreat of glaciers and the uncovering of frozen plants that had been buried for thousands of years.

"These three lines of evidence argue that the present warming and associated glacier retreat are unprecedented in some areas for at least 5,200 years," the scientists wrote in the article. "The ongoing global-scale, rapid retreat of mountain glaciers is not only contributing to global sea-level rise but also threatening freshwater supplies in many of the world's most populous regions," the article further quoted.

The research comes after some 50 scientific expeditions to seven mountain glaciers over the past 30 years, including the Huascaran and Quelccaya ice caps in Peru, the Sajama ice cap in Bolivia and the Dunde and Puruogangri ice caps in China.

Professor Thompson said, "We have a record going back 2,000 years and when you plot it out, you can see the medieval warm period [from 1000 to 1300] and the little ice age [from 1600 to 1850]. And in that same record, you can clearly see the 20th century and the thing that stands out is how unusually warm the last 50 years have been. There hasn't been anything like it, not even in the medieval warm period.”

He further said, “The fact that the isotope values in the last 50 years have been so unusual means that things are dramatically changing.”

Thompson says the most dramatic authentication comes from 28 sites where the retreating ice has exposed plants that have been frozen and preserved for between 5,000 and 6,000 years by the glacier's base.

"This means that the climate at the ice cap hasn't been warmer than it is today in the last 5,000 years or more," Professor Thompson said. "If it had been, then the plants would have decayed," he added.

However, Thompson does not give a reason for such an abrupt change, but says evidence from such diverse sources as Mount Kilimanjaro, African lakes, Greenland and Antarctic ice cores, the Andes and the Alps indicates a sudden arrival of cool and often wet conditions, all about the same time.