Melting glaciers may add 10 inches to sea levels worldwide by 2100: Report

It estimates that glaciers worldwide are likely to lose anywhere from 18-36% of their mass by 2100.

Melting glaciers worldwide could result in almost 10 inches of sea level rise by the end of this century, a study warns.

The research, published in the Journal of Glaciology, indicates that the smaller glaciers could play a much larger role in sea level rise than researchers had previously thought.

The review is the most comprehensive global comparison of glacier simulations ever compiled, researchers said.

It estimates that glaciers worldwide are likely to lose anywhere from 18 to 36 per cent of their mass by 2100.

"The clear message is that there's mass loss -- substantial mass loss -- all over the world," said Regine Hock, from the University Alaska Fairbanks in the US.

The anticipated loss of ice varies by region, but the pattern is evident.

"We have more than 200 computer simulations, and they all say the same thing. Even though there are some differences, that's really consistent," Hock said.

This is the only comprehensive and systematic endeavour to date to compare global-scale glacier models and their projections.

The study compared 214 glacier simulations from six research groups around the world and "all of them paint the same picture," Hock said.

Researchers examined the mass changes for over 200,000 glaciers worldwide, totalling an area equal to the size of Texas.

The study does not include the vast ice sheets in Greenland or Antarctica, whose behaviour is different from mountain and land-based glaciers and which require unique modeling methods.

The results indicate that the smaller glaciers could play a much larger role in sea level rise than researchers had previously thought.

Most research has focused on ice sheets in Greenland and Antarctica, due to their size and prominence, but the effect of smaller glaciers is significant.

"We confirm that they are really substantial contributors to sea level rise," Hock said.

For example, Alaska's 25,000 glaciers will lose between 30 per cent and 50 per cent of their mass by the end of this century. Once they do, Alaska will be the largest global regional sea level contributor in Northern Hemisphere, apart from Greenland.

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Nasa launching laser satellite today to study Earth's changing ice

ICESat-2 will improve upon NASA's 15-year record of monitoring the change in polar ice heights.

NASA is launching a laser-armed satellite next month that will measure -- in unprecedented detail -- changes in the heights of Earth's polar ice to understand what is causing ice sheets to melt fast.

In recent years, contributions of melt from the ice sheets of Greenland and Antarctica alone have raised global sea level by more than a millimeter a year, accounting for approximately one-third of observed sea level rise, and the rate is increasing.

Called the Ice, Cloud and Land Elevation Satellite-2 (ICESat-2), the mission is scheduled to be launched from Vandenberg Air Force Base in California on September 15, NASA said in a statement late on Thursday.

ICESat-2 will measure the average annual elevation change of land ice covering Greenland and Antarctica to within the width of a pencil, capturing 60,000 measurements every second.

"The new observational technologies of ICESat-2 will advance our knowledge of how the ice sheets of Greenland and Antarctica contribute to sea level rise," said Michael Freilich, Director of the Earth Science Division in NASA's Science Mission Directorate.

ICESat-2 will improve upon NASA's 15-year record of monitoring the change in polar ice heights.

It started in 2003 with the first ICESat mission and continued in 2009 with NASA's Operation IceBridge, an airborne research campaign that kept track of the accelerating rate of change.

ICESat-2's Advanced Topographic Laser Altimeter System (ATLAS) measures height by timing how long it takes individual light photons to travel from the spacecraft to Earth and back.

"ATLAS required us to develop new technologies to get the measurements needed by scientists to advance the research," said Doug McLennan, ICESat-2 Project Manager.

"That meant we had to engineer a satellite instrument that not only will collect incredibly precise data, but also will collect more than 250 times as many height measurements as its predecessor," he added.

ATLAS will fire 10,000 times each second, sending hundreds of trillions of photons to the ground in six beams of green light.

With so many photons returning from multiple beams, ICESat-2 will get a much more detailed view of the ice surface than its predecessor.

As it circles Earth from pole to pole, ICESat-2 will measure ice heights along the same path in the polar regions four times a year, providing seasonal and annual monitoring of ice elevation changes.

Beyond the poles, ICESat-2 will also measure the height of ocean and land surfaces, including forests.

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