By Joe Romm, Posted: 26 Jul 2012 09:31 AM PDT at http://thinkprogress.org/climate/2012/07/26/588611/study-decline-in-arctic-sea-ice-up-to-95-man-made/
The radical decline in sea ice around the Arctic is at least 70% due to human-induced climate change, according to a new study, and may even be up to 95% down to humans – rather higher than scientists had previously thought.
The loss of ice around the Arctic has adverse effects on wildlife and also opens up new northern sea routes and opportunities to drill for oil and gas under the newly accessible sea bed.
The reduction has been accelerating since the 1990s and many scientists believe the Arctic may become ice-free in the summers later this century, possibly as early as the late 2020s.
So begins the UK Guardian story on a new open access (!) study in in the journal Environmental Research Letters, “Sources of multi-decadal variability in Arctic sea ice extent.”
This study appears consistent with a recent Geophysical Research Letters paper, “Observations reveal external driver for Arctic sea-ice retreat” (see Study: ‘Virtually’ Certain Impact Of Manmade ‘Climate Change Is Observable In Arctic Sea Ice Already Today’).
Arctic ice loss has many harsh negative consequences for humanity and the local biodiversity. First, it eliminates a primary habitat for polar bears and other species. “The survival of polar bears as a species is difficult to envisage under conditions of zero summer sea-ice cover,” concludes the 2004 Arctic Climate Impact Assessment, by leading scientists from the eight Arctic nations, including the United States.
Second, a 2008 study led by David Lawrence of the National Center for Atmospheric Research (NCAR) concluded (see “Tundra 4: Permafrost loss linked to Arctic sea ice loss“):
We find that simulated western Arctic land warming trends during rapid sea ice loss are 3.5 times greater than secular 21st century climate-change trends. The accelerated warming signal penetrates up to 1500 km inland”¦.
In other words, if it continues, the recent trend in sea ice loss may triple overall Arctic warming, causing large emissions in carbon dioxide and methane from the tundra this century (for a review of recent literature, see “Nature: Climate Experts Warn Thawing Permafrost Could Cause 2.5 Times the Warming of Deforestation!“). Such accelerated warming would also presumably accelerate the melting of the Greenland ice sheet.
Read the rest of the article at http://thinkprogress.org/climate/2012/07/26/588611/study-decline-in-arctic-sea-ice-up-to-95-man-made/.