Should we worry about 2010′s near-record melting of sea ice?
Summary: No. It’s weather, not climate change. Many of the people sounding the alarms know they are exaggerating the situation. This is a follow-up to It’s time to worry (again) about disappearing arctic ice (8 June 2010); see that for excellent graphs of the long-term sea ice history.
We’re told that polar sea ice is shrinking at an unusually rapid rate this year, and global warming is responsible. This would be disturbing — if it were true. In fact it is much ado about nothing.
- Polar sea ice is not shrinking at an unusually rapid rate this year
- The major short-term factor affecting arctic sea ice loss: the wind
- Soot, one of the major long-term factor melting polar ice
- Other posts about earth’s melting ice, an afterword, and contact information
(1) Polar sea ice is not shrinking at an unusually rapid rate this year
As explained in the June post:
- Earth has two poles. Cryosphere Today shows the area of global sea ice today is aprox at the 1979-2010 average. Arctic sea ice is low; antarctic sea ice is above average.
- The rate of annual shrinkage does not correlate well with the size of the annual minimum.
- The record of sea ice area goes back to 1979. It is too short a basis on which to draw strong conclusions due to the existence of long climate rhythms.
(2) The major short-term factor affecting arctic sea ice loss: the wind
Wind strength and patterns cause much of the annual variation in the minimum area and extent of the arctic ice.
(a) The 2007 and 2010 declines in polar sea ice result mostly from winds. The guilty party is The Arctic dipole anomaly, as explained by the National Snow and Ice Data Center, June 2010
The record low ice extent of September 2007 was influenced by a persistent atmospheric pressure pattern called the summer Arctic dipole anomaly (DA). The DA features unusually high pressure centered over the northern Beaufort Sea and unusually low pressure centered over the Kara Sea, along the Eurasian coast. In accord with Buys Ballot’s Law, this pattern causes winds to blow from the south along the Siberian coast, helping to push ice away from the coast and favoring strong melt. The DA pattern also promotes northerly winds in the Fram Strait region, helping to flush ice out of the Arctic Ocean into the North Atlantic. The DA pattern may also favor the import of warm ocean waters from the North Pacific that hastens ice melt.
June 2010 saw the return of the DA, but with the pressure centers shifted slightly compared to summer 2007. As a result, winds along the Siberian coastal sector are blowing more from the east rather than from the south. Whether or not the DA pattern persists through the rest of summer will bear strongly on whether a new record low in ice extent is set in September 2010.
The following material is from the June post about sea ice.
(b) For non-technical explanations see these articles:
- “NASA Examines Arctic Sea Ice Changes Leading to Record Low in 2007“, NASA, 1 October 2007 — “Nghiem said the rapid decline in winter perennial ice the past two years was caused by unusual winds..”
- “Wind contributing to Arctic sea ice loss, study finds“, The Guardian, 22 March 2010 — “New research does not question climate change is also melting ice in the Arctic, but finds wind patterns explain steep decline.”
(c) Some of the research about wind’s effect on the arctic, including the 2 studies described above:
- “Rapid reduction of Arctic perennial sea ice“, S. V. Nghiem, Geophysical Research Letters, 4 October 2007 — Free copy here.
- “Summer retreat of Arctic sea ice: Role of summer winds“, Masayo Ogi, Geophysical Research Letters, 18 December 2008 — Free copy here.
- “Influence of winter and summer surface wind anomalies on summer Arctic sea ice extent“, Masayo Ogi et al, Geophysical Research Letters, 2 April 2010 — Free copy here.
(3) Soot, one of the major long-term factor melting polar ice:
(a) For non-technical explanations see:
- “Soot’s Dirty Hand in Global Warming“, Scientific American, 8 February 2001
- “Soot More Culpable in Climate Warming Than Expected“, Scientific American, 23 December 2003
- “Impure as the Driven Snow“, Scientific American, 8 June 2007 — “Soot is a bigger problem than greenhouse gases in polar meltdown.”
(b) Some of the large research literature about the effect on climate of soot (black carbon) deposits:
- “Soot climate forcing via snow and ice albedos“, James Hansen and Larissa Nazarenko, Proceedings of the National Academy of Sciences, 13 January 2004
- “Climate response of direct radiative forcing of anthropogenic black carbon“, Serena H. Chung and John H. Seinfeld, Journal of Geophysical Research, 1 June 2005 — Free copy here.
- “Aerosol organic carbon to black carbon ratios: Analysis of published data and implications for climate forcing“, T. Novakov, Journal of Geophysical Research, 8 November 2005 — Free copy here.
- Present-day climate forcing and response from black carbon in snow“, Mark G. Flanner at al, Journal of Geophysical Research, June 2007 — Free copy here.
- “Global and regional climate changes due to black carbon“, V. Ramanathan and G. Carmichae, Nature Geoscience, April 2008 — Free copy here.
- “Black soot and the survival of Tibetan glaciers“, Baiqing Xu et al, Proceedings of the National Academy of Sciences, 29 December 2009
- List of articles, with links, about black carbon deposits’ effect on climate, AGW Observer
(4a) Other posts about Earth’s melting ice
- The media doing what it does best these days, feeding us disinformation, 18 February 2009 — About the article that ignited a media smokescreen to conceal the facts.
- George Will: climate criminal or brave but sloppy iconoclast?, 23 February 2009
- About that melting arctic ice cap, 17 April 2010
- Apologies are due George Will, vindicated from charges that he is a climate criminal, 22 April 2010
- Aerosols (pollutionants, like soot) as a driver of climate change, 8 May 2009
- A look at the temperature record of Alaska – any sign of global warming?, 17 May 2009
- Fear or Fail: about the melting Greenland ice sheet, 24 May 2010
- It’s time to worry (again) about disappearing arctic ice, 8 June 2010
(4b) Afterword and contact info
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