Albedo changes in the Arctic

How global warming and feedbacks are causing huge albedo changes in the Arctic.

Snow cover decline

Decline of the snow cover on land in the northern hemisphere is accelerating, as illustrated by the image below and the image underneath on the right. (1)

Image credit: Rutgers University

Fresh snow can have an albedo as high as 0.85, meaning that up to 85% of the sunlight falling on snow can get reflected back into space. As the snow melts, its structure changes making it less reflective, i.e. its albedo will go down, to as low as 40%. (2)

As a result, more sunlight gets absorbed, accelerating the melting process. Eventually, where snow melts away, spots of bare soil become exposed, and dark wet soil has a very low albedo, reflecting only between 5% and 15% of the sunlight. Thus, even more sunlight gets absorbed and the soil's temperature increases, causing more of the remaining snow to melt. (2)

Changes in vegetation can further accelerate this process. Russia's boreal forest - the largest continuous expanse of forest in the world - has seen a transformation in recent years from larch to conifer trees. Larch trees drop their needles in the fall, allowing the vast, snow-covered ground in winter to reflect sunlight and heat back into space and helping to keep temperatures in the region very cold. But conifers such as spruce and fir retain their needles, which absorb sunlight and increase the forest's ground-level heat retention. (3)

Albedo, from Wikipedia

A conversion from larch to evergreen stands in low-diversity regions of southern Siberia would generate a local positive radiative forcing of 5.1±2.6 W m−2. This radiative heating would reinforce the warming projected to occur in the area under climate change. (4)

Tundra in the Arctic used to be covered by a white blanket of snow most of the year. However, as the landscape is warming up, more trees and shrubs appear. Scientists who studied part of the Eurasian Arctic, found that willow and alder shrubs, once stunted by harsh weather, have been growing upward to the height of trees in recent decades. They now rise above the snowfall, presenting a dark, light-absorbing surface. This increased absorption of the Sun's radiation, combined with microclimates created by forested areas, adds to global warming, making an already-warming climate warm even more rapidly. (5 & 6)

Furthermore, encroachment of trees onto Arctic tundra caused by the warming may cause large release of carbon to the atmosphere, concludes a recent study. This is because tundra soil contains a lot of stored organic matter, due to slow decomposition, but the trees stimulate the decomposition of this material. (7)


Sea ice decline

In the Arctic, sea ice volume has fallen dramatically over the years, as illustrated by the image on the right. The trend points at 2014 as the year when Arctic sea ice will first reach zero volume for some time during that year. (8)

The Arctic Ocean looks set to be ice-free for a period of at least three months in 2015 (August, September and October), and for a period of at least 6 months from the year 2020 (June through to November). (9)

Decline of the Arctic sea ice is accelerating, due to numerous feedbacks. As the Arctic atmosphere warms up, any snow cover on top of the ice will melt away ever quickly, decreasing the surface albedo and thus reinforcing the warm-up. As melt ponds appear on top of the ice, the albedo will drop even further.

Sam Carana's Diagram of Doom pictures ten feedbacks that jointly work to accelerate sea ice decline. (10)

The image below shows the three areas where albedo change will be felt most in the Arctic, i.e. sea ice loss, decline of albedo in Greenland and more early and extensive retreat of snow and ice cover in other areas in the Arctic. (8)

Big changes in the Arctic within years, by Sam Carana

References

1. Northern Hemisphere Snow Cover Anomalies 1967-2012 June, Rutgers University
climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=6

2. Albedo, Albedo Change blog
albedochange.blogspot.com/2009/02/albedo-change.html

3. Shift in Northern Forests Could Increase Global Warming, Scientific American, March 28, 2011
scientificamerican.com/article.cfm?id=shift-northern-forests-increase-global-warming

4. Sensitivity of Siberian larch forests to climate change, Shuman et al., April 5, 2011, Wiley.com
onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2011.02417.x/abstract

5. Warming turns tundra to forest
ox.ac.uk/media/news_stories/2012/120604.html

6. Eurasian Arctic greening reveals teleconnections and the potential for structurally novel ecosystems, Macias-Fauria et al., 2012
nature.com/nclimate/journal/v2/n8/full/nclimate1558.html

7. Expansion of forests in the European Arctic could result in the release of carbon dioxide, University of Exeter news, June 18, 2012
exeter.ac.uk/news/featurednews/title_214902_en.html

8. Big changes in the Arctic within years, Sam Carana, October 26, 2012, Arctic-News blog
arctic-news.blogspot.com/2012/10/big-changes-in-arctic-within-years.html

9. Getting the Picture, Sam Carana, August 2012, Arctic-News blog
arctic-news.blogspot.com/2012/08/getting-the-picture.html

10. Diagram of Doom, Sam Carana, August 2012, Arctic-News blog
arctic-news.blogspot.com/2012/08/diagram-of-doom.html


Further reading

- Albedo change in the Arctic
arctic-news.blogspot.com/2012/07/albedo-change-in-arctic.html

- Greenland is melting at incredible rate
arctic-news.blogspot.com/2012/07/greenland-is-melting-at-incredible-rate.html

- Albedo change in the Arctic threatens to cause runaway global warming
arctic-news.blogspot.com/2012/10/albedo-change-in-the-arctic-threatens-to-cause-runaway-global-warming.html

Methane contributes to accelerated warming in the Arctic

Above combination image featured earlier in the post Striking increase of methane in the Arctic. The images were produced by Dr. Leonid Yurganov, Senior Research Scientist, JCET, UMBC, who presented his findings at the AGU Fall Meeting 2012. The image below gives an update for 2012, showing an image with methane levels at 600 hPa.

Temperature anomalies on the inset on above image are averages for the full month November, whereas the methane levels displayed on the left are for the first ten days of November only. Using temperature maps for the same periods in such comparisons may result in even more striking simularities between methane levels and temperatures. For a more complete picture, further comparisons between November 2008 and November 2012 are added, for days 11-20 (below),

and for days 21-30 (below).

The images show that the highest methane levels show up above the water, as opposed to above land, indicating that methane is being released from the seabed across the Arctic.

Temperatures have meanwhile changed. In November 2012, there were high temperature anomalies in east Siberia. There now are very low temperatures throughout Siberia, as illustrated by the Wunderground map below, which shows high temperatures. Temperatures as low as -60.5°F (-51.4°C) were recorded in Susuman, east Siberia, both on December 13th and 17th, 2012.

The now hugely deformed polar jet stream and high levels of methane in the Arctic are only two out of numerous feedbacks that contribute to accelerate warming in the Arctic. Without rapid action, we can expect such wild swings in temperature to get even worse, making more extreme weather the new norm.

Polar jet stream appears hugely deformed

World climate zones used to be kept well apart by jet streams. On the northern hemisphere, the polar jet stream was working hard to separate the Tundra and Boreal climate zones' colder air in the north from the Temperate climate and the Subtropical climate zones' warmer air in the south.

NOAA image

The greater the difference in temperature between north and south, the faster the jet streams spin around the globe, the polar jet stream at about 60°N and the subtropical jet stream at about 30°N, as illustrated on above image. 

NOAA image

The polar jet stream used to move at speeds of up to 140 miles per hour, while following a relatively straight track that was meandering only slightly, i.e. with waves that go up and down only a little bit.

Accordingly, the Northern Temperate Zone used to experience only mild differences between summer and winter weather, rather than the extreme hot or cold temperatures that we've experienced recently.

Accelerated warming in the Arctic is decreasing the difference in temperature between the Arctic and the Northern Temperate Zone. This is causing the polar jet to slow down and become more wavy, i.e. with larger loops, as illustrated by the NASA image further below.

Polar jet stream (blue) & subtropical
jet stream (red) - NOAA image

                   Diagram of Doom, Sam Carana

This is a feedback of accelerated warming in the Arctic that reinforces itself. As the jet stream slows down and its waves become more elongated, cold air can leave the Arctic more easily and come down deep into the Northern Temperate Zone. Conversily, more warm air can at the same time move north into the Arctic.

The 'open doors' feedback further decreases the difference in temperature between the Arctic and the Northern Temperate Zone, in turn further slowing down the jet stream and making it more wavy, and thus further accelerating warming in the Arctic.

The polar jet stream can travel at speeds greater than 100 mph. Here, the fastest winds are colored red; slower winds are blue. View animated version here. Credit: NASA/Goddard Space Flight Center

How does this affect temperatures? If we look at the average surface temperature anomalies for the month November 2012, we see huge differences in temperatures. Areas in the East Siberian Sea and in east Siberia registered average surface temperature anomalies for November 2012 of about 10 degrees Celsius, compared with 1951-1980. At the same time, areas in Alaska and Canada have been experiencing anomalies of about -10 degrees Celsius.

This suggests a hugely deformed polar jet stream, as indicated by the contour lines on above image on the right. This is very worrying, as this is only one out of many feedbacks that come with accelerated warming in the Arctic. There are at least ten such feedbacks, as depicted in the diagram below, from the earlier post Diagram of Doom.

       Diagram of Doom, Sam Carana

One of the most frightening feedbacks is the albedo loss in the Arctic. The speed at which changes are taking place can be illustrated with the image below, from the earlier post Big changes in the Arctic within years.

The urgency to act is perhaps best expressed by means of the two images below, which can constitute a fitting end-of-year message if you like to share them further. The image below highlights that Arctic sea ice minimum volume in 2012 was only 19.3% what it was in 1979. The background image, prepared by Wipneus, shows an exponential trend projecting a 2013 minimum of only 2000 cubic km of sea ice, with a margin of error that allows Arctic sea ice to disappear altogether next year, i.e. nine months from now.

Finally, the image below highlights that, in 2012, Arctic sea ice area fell by 83.7% in just 168 days, again illustrating how fast things can eventuate. 

For more quotes, see the page at http://arcticmethane.blogspot.com/p/quotes.html

Earlier posts:
- Opening the Doorways to Doom

- Opening further Doorways to Doom

- Diagram of Doom

- How to avert an intensifying food crisis

- Albedo change in the Arctic threatens to cause runaway global warming

- Big changes in Arctic within years

Paul Beckwith at Radio Ecoshock

Paul Beckwith was recently interviewed by Ecoshock Radio, for a show that will go live to over 50 radio stations on three continents from Tuesday December 18 onward. Paul speaks about Arctic albedo collapse and our "new" climate, and more.

An mp3 file for the earlier part of the show is already available at Radio Ecoshock.