Ice cores from the Guliya Glacier in Tibet's Kunlun Mountains reveal that average temperature in the region has risen 2.7 degrees Fahrenheit (1.7 degrees Celsius) in the last 50 years and average precipitation 2.1 inches (5.33 centimeters) in the past 25. The research results are further confirmation that climate warming is taking place faster at high elevations than at sea level.
That's worrisome as hundreds of millions of people worldwide depend on high-altitude glaciers for freshwater. The Guliya Glacier where the science team extracted five ice cores – including one of the world's longest – is one of many frozen reservoirs dotting the Tibetan Plateau that supply freshwater to Central, South and Southeast Asia.
Evidence of climate change from Stone Age Ice
“There are 46,000 mountain glaciers in the world, and they are the water source for major rivers,” said Lonnie Thompson, a paleoclimatologist at Ohio State University co-led the international research team.
“The ice cores actually demonstrate that warming is happening, and is already having detrimental effects on Earth’s freshwater ice stores. Generally, the higher the elevation, the greater the rate of warming that’s taking place,” according to an EarthSky news report.
Located in Tibet's western Kunlun Mountains, the Guliya Glacier is one of the largest freshwater repositories outside of the Arctic and Antarctica. Ice at the bottom of one of the cores is said to have been deposited more than 600,000 years ago during the Stone Age long before modern humans were present. Nearly as long as the Empire State Building is tall, the longest ice core measures more than 1,000 feet (300 meters) in length.
An international team of scientists from China and the U.S. are analyzing the chemistry of the layers of compacted snow and ice in the cores deposited over millennia for evidence of changes in climate. Thompson said data the research team is gathering provides evidence that temperatures at some of the highest, coldest mountain peaks in the world are rising rapidly.
The oldest ice core drilled in the Northern Hemisphere was obtained in Greenland in 2004 during the North Greenland Ice Core Project, EarthSky notes. The ice therein dates back some 120,000 years. The oldest ice core ever recovered comes from Antarctica and dates back 800,000.
The U.S.-Chinese research team is digging deeper into their analysis of the Guliya Glacier ice cores in search of additional chemical evidence related to climate change. More specifically, they'll look for clues regarding changes in temperature caused by patterns of ocean circulation in both the North Atlantic and tropical Pacific Oceans.
Those oceanic currents drive seasonal precipitation, including the Tibet and Indian monsoons. Hence, they're of vital interest to populations throughout Central, South and Southeast Asia.
*Images credit: Ohio State University