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Arctic sea ice set to hit record low | Arctic sea ice set to hit record low |
(40 minutes later) | |
By Mark Kinver Environment reporter, BBC News | |
Arctic sea ice looks set to hit a record low by the end of the month, according to satellite data. | Arctic sea ice looks set to hit a record low by the end of the month, according to satellite data. |
Scientists at the US National Snow and Ice Data Center said data showed that the sea ice extent was tracking below the previous record low, set in 2007. | Scientists at the US National Snow and Ice Data Center said data showed that the sea ice extent was tracking below the previous record low, set in 2007. |
Latest figures show that on 13 August ice extent was 483,000 sq km (186,000 sq miles) below the previous record low for the same date five years ago. | Latest figures show that on 13 August ice extent was 483,000 sq km (186,000 sq miles) below the previous record low for the same date five years ago. |
The ice is expected to continue melting until mid- to late September. | The ice is expected to continue melting until mid- to late September. |
"A new daily record... would be likely by the end of August," the centre's lead scientist, Ted Scambos, told Reuters. | "A new daily record... would be likely by the end of August," the centre's lead scientist, Ted Scambos, told Reuters. |
"Chances are it will cross the previous record while we are still in ice retreat." | "Chances are it will cross the previous record while we are still in ice retreat." |
'Rapid melt' | 'Rapid melt' |
Sea ice extent refers to a measurement of the area of Arctic Ocean that contains at least some sea ice. Areas with less that 15% is considered by scientists to mark the ice edge. | Sea ice extent refers to a measurement of the area of Arctic Ocean that contains at least some sea ice. Areas with less that 15% is considered by scientists to mark the ice edge. |
In its latest summary, the centre said the average rate of ice loss since late June had been "rapid", with just over 100,000 sq km melting each day. | In its latest summary, the centre said the average rate of ice loss since late June had been "rapid", with just over 100,000 sq km melting each day. |
However, it added, the rate of loss doubled for a few days earlier this month during a major storm. | However, it added, the rate of loss doubled for a few days earlier this month during a major storm. |
Responding to the latest update, Prof Seymour Laxon, professor of climate physics at University College London, said that he was not surprised that 2012 was set to deliver a record minimum. | |
"We got very close to a record minimum last year," he told BBC News. | |
"The fact that Cryosat showed thinner ice last winter, it is not surprising to me that it looks like we will have a record minimum this year. | |
Cryosat is a radar spacecraft operated by the European Space Agency (Esa) that was launched in 2010 to monitor changes in the thickness and shape of polar ice. | |
Prof Laxon added that this year's projected record minimum could result in a change in projections of when the Arctic would be sea ice-free during summer months. | |
"The previous [Intergovernmental Panel on Climate Change] report (published in 2007) stated that the likely date for an ice-free Arctic in the summer - and definitions for this vary a bit - was 2100," he explained. | |
"When we had the 2007 minimum, that date was brought forward to 2030-2040. | |
"The fact that we look set to get another record ice minimum in such a short space of time means that the modellers may once again need to go and look at what their projections are telling them." | |
Arctic sea ice plays a key role in help keep polar regions cool and helps control the global climate system. | Arctic sea ice plays a key role in help keep polar regions cool and helps control the global climate system. |
As the ice has a bright surface, it reflects about 80% of the sunlight that hits it back into space. | As the ice has a bright surface, it reflects about 80% of the sunlight that hits it back into space. |
When the sea ice melts, it exposes more of the dark ocean surface, resulting in 90% of the sunlight being absorbed, which warms the Arctic ocean. | When the sea ice melts, it exposes more of the dark ocean surface, resulting in 90% of the sunlight being absorbed, which warms the Arctic ocean. |