Climate Impacts of Disappearing Sea Ice

[phantom power]

A google search on "climate impact of ice free arctic" does not yield much in the way of research citations. Now that we know the arctic will be seasonally ice free in the near future, I'd love to see some simulations on likely climate impacts.

Anybody who ever lived in a lake effect snow zone knows that whether the Great Lakes are covered with ice or open water makes a Big Fucking Difference on weather down-wind.

The impacts of an ice-free Arctic are far-reaching, and could be a trigger for abrupt, cataclysmic climate change in the future. Although it is difficult to see exactly how sea ice decline will impact the local and global environment, basic understanding of the Arctic as well as recent observations give us a good idea of how things might change.

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Weather patterns

Continued loss of Arctic sea ice may dramatically alter global weather and precipitation patterns in the decades to come. The jet stream will probably move further north in response to warmer temperatures over the pole, which will bring more precipitation to the Arctic. More frequent and intense droughts over the U.S. and other regions of the mid-latitudes may result from this shift in the jet stream. Changes to the course of the jet stream affect weather patterns for the entire planet, and we can expect impacts on the strength of the monsoons and recurvature likelihood of hurricanes. During 1979 to 2006, years that had unusually low summertime Arctic sea ice also had a 10-20% reduction in the temperature difference between the Equator and the North Pole. This resulted in reduced winter precipitation over all of the U.S., Alaska, and Northern Europe. In contrast, increased precipitation fell over Spain, Italy, and Japan during these winters. Although intense La Niña or El Niño events can have a much stronger influence on wintertime weather patterns, reduced summertime Arctic sea ice should give most of the Northern Hemisphere a delayed start to winter during most years for the foreseeable future.

Global ocean circulation

Surface global ocean currents are driven by the winds, but the vertical ocean circulation is determined by the temperature and salt content of the water (hence, is called the thermohaline circulation). The engine of the thermohaline circulation is in the North Atlantic, where warm surface waters travel north past Greenland and into the Arctic on the Gulf Stream current. As the warm water reaches cold air, evaporation cools the water, and sea ice formation increases the salinity (salt content) of the surrounding water (ice rejects the salt as it freezes). This new cold, salty water is very dense, and sinks in a process called overturning. This sinking motion in the Arctic is a driving force behind the "global conveyor belt," and the formation and maintenance of sea ice is a the heart of it all. Not only could the slowdown of new sea ice formation lead to the abatement of the thermohaline circulation, but as sea ice melts, it injects massive quantities of freshwater into the Arctic Ocean. The freshening of Arctic sea water due to manmade climate change could lead to exceptional changes in the world's ocean circulation and thus Earth's climate as well.

Ecosystems

Sea ice is important in marine ecosystems in at least three ways. First, it provides a habitat for algae and invertebrates and fish, and regulates the temperature of the water below it. Although it seems counterintuitive, the sea ice insulates the water beneath it, keeping it from becoming too cold. Second, as the ice melts in the summer, it releases the organisms into the water, providing fuel for Arctic marine food webs. Finally, it provides breeding and hunting grounds for marine mammals and birds that call the chilly North their home.

The impacts of melting ice extend well beyond polar bears (which are one step away from endangered on the Conservation Scale). Birds, seals, and whales also use the ice for hunting. Birds nest in the sea ice and use it for protection while raising their young in the potentially deadly environment of the Arctic. The retreat of sea ice, especially in the warm winter months, has decreased the available platforms that seals, walruses, and polar bears use to rest on and hunt from. Scientists estimate that retreating sea ice will result in a loss of 2/3 of the polar bear population, and force the remaining bears into a smaller, iceless area.

http://www.wunderground.com/climate/SeaIce.asp#impacts

[Bigmack]

1. Oddly enuf, from what i've read

increasing fresh water in the north Atlantic and the more southerly sinking of the thermohaline current could actually trigger SIGNIFICANT cooling in northern Europe. Irony of ironies! Ms Bigmack

[phantom power]

2. changing ocean currents are a possible factor

I'm reading the phrase "runaway methane release" with increasing frequency, which makes me feel a little queasy.

[pscot]

3. I wonder what happens if i push this red button?

[Junkdrawer]

4. Add to that: "Climate change accelerating Southwest desertification, speaker says"

Jonathan Overpeck, professor of Atmospheric Sciences and Geosciences at the University of Arizona, brought a friendly smile, informative graphics and a warning about drought in the Southwest to Sandia’s Climate Change and National Security Speaker Series.

Addressing “Climate Change and the Aridification of the North American Southwest and Beyond,” Overpeck placed water-glass graphic images at key water-storage locations in the Southwest to show how full the reservoirs are.

Many glasses are more than half-empty, he said, and computer simulations predict the situation will worsen.

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But the major problem facing the Southwest, he said, is drought. Water managers are used to dry years with occasional wet years, he said. “How would you adapt to a 51-year drought?” such as what Native Americans apparently faced nearly a thousand years ago in roughly the same locale, he asked.

Even now, water storage in many reservoirs is below average, he said, and southwestern river systems are over-allocated. The warmer the weather, the greater the impact of drought, and the weather is getting warmer, Overpeck said.

“More greenhouse gases mean less snow, drier soils, less late winter snow and rain, less water in rivers, along with more flooding and more frequent and severe droughts,” he said. “The mega-drought risk is substantial.”

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https://share.sandia.gov/news/resources/news_releases/climate_southwest/

The Great Experiment....I don't remember signing the participant's waiver....