PARIS • Glaciers worldwide have shrunk to levels not seen in 120 years of record-keeping, with melting accelerating in the first decade of the 21st century, according to a study released yesterday.
On average, glaciers currently lose between 50cm and 150cm of thickness every year, reported the study, which was published in the Journal Of Glaciology.
The melting of glaciers and ice sheets has accelerated as the planet heats up because of climate change, scientists say.
"This is two to three times more than the corresponding average of the 20th century," said Dr Michael Zemp, director of the World Glacier Monitoring Service and the study's lead author.
More than a billion people, especially in Asia and South America, get more than half of their drinking water from the seasonal melting of snow and glacier ice, previous research has shown.
The current rate of global glacier melt is without precedent for the 120 years covered by scientific observation, and probably for much longer, Dr Zemp added.
Moreover, accelerated ice loss has created a dynamic whereby glaciers in many regions will continue to diminish even if global warming did not continue to raise global temperatures.
Preliminary data from the last five years, not covered in the study, suggests that the rapid decline of ice mass is continuing apace.
The 20th-century record ice loss observed in 1998 "has been exceeded in 2003, 2006, 2011, 2013, and probably again in 2014", Dr Zemp said. World nations are under increasing pressure to curb greenhouse gas emissions to limit the pace of global warming.
The glacier study comes as United States President Barack Obama was set to announce early today what he called the "biggest, most important step we've ever taken" in the fight against climate change.
The White House was to release the final version of America's Clean Power Plan, a set of environmental rules and regulations that will home in on pollution from the nation's power plants, setting limits on power-plant carbon emissions for the first time.
Plants will have to reduce carbon dioxide emissions by 32 per cent from 2005 levels by 2030, in an ambitious drive which will boost the renewable-energy sector but which is already facing stern opposition.
Briefing material released by the White House ahead of the announcement said the Clean Power Plan would avoid up to 3,600 premature deaths, lead to 90,000 fewer asthma attacks in children and prevent 300,000 missed work and school days.
It would also create tens of thousands of jobs and drive more aggressive investment in clean energy technologies.