Arctic sea ice thickness falls by 2m in 21 days in some areas

For years, warnings have been raised about the dramatic decline of Arctic sea ice. Various posts at this blog have also analyzed the exponential nature of the decline in summer sea ice volume and the many feedbacks that fuel this decline. And for years, the conclusion has been that - without action - the sea ice looks set to disappear altogether within years.

Yet, many are still ignoring this warning, often with remarks such as "some of the ice is 5 meters thick; it would take decades for all that ice to melt!" Thick ice does indeed pile up along the northern coast of Greenland and Ellesmere Island, due to the way the ice drifts. This has lead some to argue that an S-shaped curve (sigmoid or gompertz trendline) was more appropriate, with the decline in sea ice volume slowing down as it approaches zero.

However, this argument doesn't seem make much sense, since such a S-shaped trendline would only apply to a relatively small area with very thick sea ice. Exponential curves would still remain the best fit to predict the decline of the sea ice in the Arctic Ocean at large.

Moreover, is it really more appropriate to say that summer sea ice looks set to virtually disappear within years, with just a tiny sliver of ice remaining north of Greenland and Ellesmere Island, instead of saying that the sea ice looks set to disappear altogether within years? How persistent will such a sliver really be?

One of the feedbacks of sea ice decline is that, as the decline progresses, cyclones can be expected to hit the remaining sea ice ever harder. How much damage can such cyclones and further feedbacks do? A previous post describes thin spots developing in the sea ice under the influence of a cyclone. The image below shows areas at the center of the Arctic Ocean (large circle) where thickness of the sea ice fell from 2 meters to 1 meters over a period of 21 days. Furthermore, the image below also shows that, over this period, 5m-thick ice was reduced to 3-meters thickness (top small circle), while 2m-thick ice was reduced to zero (bottom small circle).

2m falls in thickness in 21 days - click on image to enlarge

In conclusion, without action the Arctic sea ice looks set to continue to decline exponentially, while strong feedbacks such as cyclones developing when there is more open water, look set to add to the decline and cause the Arctic sea ice to disappear completely within years. For an overview of lines of action, see this post at the methane hydrates blog.

Thin Spots developing in Arctic Sea Ice

From the start of 2013, Arctic sea ice extent has roughly followed the same path it did in 2012 when a historic record low was reached, as discussed in a previous post. At the moment, thinner spots are developing in the sea ice, as illustrated by the image below.

These thin spots are developing due to a combination of factors:

• a cyclone over the Arctic
• low North Hemisphere snow cover causing more sunlight to be absorbed, rather than reflected back into space
• warm sea surface temperatures at edges of sea ice, as illustrated by the image below
• ice thickness is very low, as illustrated by the image further below

NOAA image, click to enlarge

Arctic sea ice volume/extent ratio by Neven (click to enlarge image)

Below, a 30-day Naval Research Laboratory animation illustrating the development of the thinner spots. 

The Tornado Connection to Climate Change

By  Paul Beckwith, B.Eng, M.Sc. (Physics), Ph.D. student (Climatology) and Part-time Professor, University of Ottawa

"In 2012, 93 percent of natural catastrophes were weather-related disasters. The United States was seriously affected: it accounted for 69% of overall losses and 92% of insured losses due to natural catastrophes worldwide." ~ World Watch Institute

"America has some of the wildest weather on the planet, and it turns out those extremes – which run from heat waves and tornadoes to floods, hurricanes and droughts – carry a heavy price tag." ~ theguardian

3D look at the Moore Oklahoma thunderstorm and tornado, up to 50,000 ft. Image by Tony Petrarca
from Tony's Pinpoint Weather Blog showing the funnel touching the ground just outside of Moore. 

The mega-storm that generated the massive cyclonic system that passed over the central U.S (from May 18th through May 20th) spawned many storm systems and severe tornadoes. In Oklahoma, it took less than 1 hour for a thunderstorm system to develop into a full-blown 3 km diameter tornado of the highest size/strength (EF5). As you know, this tornado caused total devastation along a swath greater than 30 km long and about 3 km wide in the southern part of the city. Two schools and a hospital were destroyed resulting in heavy loss of life.

The actual tornado tracked through the most built up part of the city and had a length of 6.22 km (Image 2). As bad as this was, if the tornado had tracked further north by about 10 km, the path length through the built-up part of the city would have been about 28 km and likely would have resulted in FOUR TIMES MORE DAMAGE.

The high altitude jet stream guided this storm directly over Oklahoma City and was a key ingredient responsible for the extremely rapid development of the tornado witnessed. Unfortunately, the location, strength, waviness, and behavior of the jet stream is changing as a result of rapid climate change. You can get use to more “Climate Bomb” extreme weather events – there is nothing to be surprised about here.

Greenhouse gas emissions from humans have warmed the planet since about 1850; the warming rate has stepped up a notch over the past several decades, and even more so now with ‘feedbacks’ kicking in big time.

There is less snow cover on the land over northern Canada, northern Eurasia and Siberia, and there is less sea ice over the Arctic Ocean. The snow and ice reflects greater than 80% of the incoming light from the sun back into space keeping these areas colder. With less snow the dark land is uncovered and with less sea ice the dark ocean is uncovered. These both reflect much less light; only about 20% and 10% respectively. The rest is absorbed and heats the ground and sea. The melting ground is releasing methane; the warming sea heats the sea floor and that warming releases more methane. Thus, parts of the high Arctic are warming at 5 to 6 times the average global rate. The equator temperature does not change as much (even seasonally the change is only about 3°C over the year). Thus, the temperature gradient between the equator and Arctic is greatly reduced.

By basic physics and meteorology, this reduced equator-pole temperature difference slows the west to east wind component. Fast jet streams circle the earth from west to east; as they slow they become much wavier and travel much more northward and southward. Regions north of the wavy jets are cold and dry (air source is cold Arctic) while regions south of the wavy jets are hot and moist (air source is equatorial marine regions). The jet is thus an intersection of these two different types of air masses (with cold fronts and warm fronts, respectively). The large local temperature gradients give rise to large pressure gradients resulting in extreme (and very unstable) weather regions.

May 20, 2013 Moore, Oklahoma tornado

Since the wave troughs carry cold air very far south and the wave crests carry warm moist air far north, the frontal temperature gradients are larger under climate change then they were before and thus the storm magnitudes are now larger. That’s why I wrote earlier that we shouldn’t be surprised.

Global warming also brings greater ocean evaporation and warmer air can carry more water vapor – in fact, in the last 3 decades or so there has been a 4% increase in atmospheric humidity. When this water vapor condenses to forms clouds, energy is released. Greater energy in the atmosphere thus fuels more violent storms, and Climate Bombs are born.

The Oklahoma tornado is just another example of the global ‘weirding‘ that we are seeing. Our reference frame is the “old climate”, in which the equator-polar temperature gradients are smaller, but the local frontal temperature gradients are larger. In our “new climate” (in which there is much less sea ice in the Arctic) this type of tornado will be much more probable — at least while we abruptly transition from the “old” to the “new” and unfamiliar climate.

Our future is a world with much warmer global temperatures. Paleoclimate records show temperature rises of 6 to 10°C within two decades have occurred many times in the past over Greenland; in one case the rise was 16°C. I see no reason why this will not occur again.

Put your seat belt on . . . oil profits can’t save you from Climate 2.0.

[earlier published at Paul's blog at SierraClubCanada and BoomerWarrior]

Related posts

- Killer El Reno Tornado Was Widest Ever Recorded: NWS

http://www.climatecentral.org/blogs/killer-el-reno-tornado-was-widest-ever-recorded-nws

- Climate change causing US wildfire season to last longer, Congress told

http://www.guardian.co.uk/world/2013/jun/04/climate-change-america-wildfire-season

Update on Arctic Snow and Ice

Above image, adapted from the National Snow and Ice Data Center (NSIDC), shows that Arctic sea ice extent has roughly followed the same path it did in 2012 when it reached a historic record low. Highlighted on above image is the highest extent the sea ice reached in 2013, i.e. 15,113 million square km on May 14, 2013.