GREENLAND: Greenland's massive glaciers are dumping millions of tonnes of ice into the Atlantic three times faster than they were 10 years ago because of global warming. Researchers warn that this could speed up sea level rise as a result.
Scientists from the California Institute of Technology used satellite data to measure glacier movement across Greenland over the past decade. They found that warmer temperatures, up three degrees over the last 20 years alone, are speeding up the glaciers' march to the ocean.
A second - unconnected - research study also warns that we are already on a fast track to global warming given greenhouse gas levels are rising rapidly to a 55-million year record.
Greenland ice already contributes about half a millimetre per year to the global sea level rise which currently stands at three millimetres per year, the research group yesterday told the American Association for the Advancement of Science annual meeting in St Louis, Missouri. Details of the study are also published today in the journal Science.
Greenland and the Antarctic are the earth's largest repositories of landlocked ice. The former's ice sheet covers about 1.7 million sq km (5,577 million sq ft), almost the size of Mexico, and can be up to three km thick. If all of this ice disappeared, global sea level would rise by a staggering seven metres.
The Caltech team showed that ice loss due to glacier flow stood at 50 cubic km a year in 1996, but this has now reached 150 cubic km for 2005.
When findings from other groups on glacier melting and ice accumulation from snowfall are taken into account, the team reported that total Greenland ice loss actually reached 224 cubic km in 2005, up from 90 cubic km in 1996.
And things will get worse before they get better, according to a University of California Santa Cruz (UCSC) study released in Science that compares today's greenhouse gas emissions with the Paleocene-Eocene Thermal Maximum (PETM). This episode of warming 55 million years ago saw global temperatures soar by five degrees due to massive releases of carbon dioxide and methane.
UCSC's Prof James Zachos found that 4.5 trillion tonnes of these gases entered the atmosphere over a 10,000-year period during the PETM.
If present trends continue, this is the same amount of greenhouse gases that industries and automobiles will belch into the atmosphere during the next 300 years. This will boost global warming, accelerating the rate of glacier flow and ice melt.