Disappearance Of Thick Arctic Sea Ice

Disappearance Of Thick Arctic Sea Ice

Arctic clathrates currents extent feedbacks hydrates methane sea ice seafloor sediments storms thickness warm water

Unknown 8/18/2015 Add Comment

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Arctic sea ice is in a horrible state. On August 16, 2015, Arctic sea ice extent was 5.786 million square km, the smallest extent on record for this time of year except for the years 2007, 2011 and 2012, as illustrated by the image on the right.

The situation today is even worse than one might conclude when looking at sea ice extent alone. Thick sea ice is virtually absent compared to the situation in the year 2012 around this time of year, as illustrated by the image below comparing sea ice thickness on August 16, 2012 (left) with August 16, 2015 (right).

The ice used to be over 4 m thick, or over 13 ft thick, north of Greenland and the Canadian Archipelago. This thick multi-year ice has been a feature of the Arctic sea ice for over 100,000 years. It used to be there all year long, unlike the thinner ice that could melt away entirely during the melting season.

The disappearance of this thick multi-year ice is a major development. Why? Until now, the thicker multi-year sea ice used to survive the melting season, giving the sea ice strength for the next year, by acting as a buffer to absorb heat that would otherwise melt away the thinner ice. Without multi-year sea ice, the Arctic will be in a bad shape in coming years, and huge amounts of heat that would otherwise go into melting the ice will instead be warming up the Arctic Ocean, further accelerating warming of its waters.

Absence of thick sea ice makes it more prone to collapse, and this raises the question whether the sea ice could collapse soon, even this year. Sea ice works like a mirror. Without sea ice, sunlight that was previously reflected back into space, will instead be absorbed by the Arctic. Albedo changes in the Arctic alone could more than double the net radiative forcing resulting from the emissions caused by all people of the world, as calculated by Prof. Peter Wadhams back in 2012.

Furthermore, there is a danger that loss of the sea ice will weaken the currents that currently cool the bottom of the sea, where huge amounts of methane may be present in the form of free gas or hydrates in sediments. This danger is illustrated by the image below by Reg Morrison, from an earlier post.

Absence of sea ice also goes hand in hand with opportunities for storms to develop over the Arctic Ocean. Such storms could push the remaining sea ice out of the Arctic Ocean. Such storms could also mix surface heat all the way down to the seafloor, where methane could be contained in sediments.

As described in an earlier post, sea surface anomalies of over 5 degrees Celsius were recorded in August 2007 (NOAA image right). Strong polynya activity caused more summertime open water in the Laptev Sea, in turn causing more vertical mixing of the water column during storms in late 2007, as described in this study, and bottom water temperatures on the mid-shelf increased by more than 3 degrees Celsius compared to the long-term mean.

Indeed, the danger is that heat will warm up sediments under the sea, containing methane in hydrates and as free gas, causing large amounts of this methane to escape rather abruptly into the atmosphere.

The image on the right, from a study by Hovland et al., shows that hydrates can exist at the end of conduits in the sediment, formed when methane did escape from such hydrates in the past.

Heat can travel down such conduits relatively fast, warming up the hydrates and destabilizing them in the process, which can result in huge abrupt releases of methane.

Since waters can be very shallow in the Arctic, much of the methane can then rise up through these waters without getting oxidized. As the methane causes further warming in the atmosphere, this will contribute to the danger of even further methane escaping, further accelerating local warming, in a vicious cycle that can lead to catastrophic conditions well beyond the Arctic. For additional feedbacks in the Arctic, see the feedbacks page. 

At the same time, ocean heat is at a record high and there's an El Niño that's still gaining strength. This ocean heat is likely to reach the Arctic Ocean in full strength by October 2015, at a time when sea ice may still be at its minimum. The image below shows sea surface temperatures on August 16, 2015 (left) and anomalies (right).

How warm is the water entering the Arctic Ocean? Merely looking at sea surface temperatures could make one overlook the full extent of the predicament we are in. Ocean heat traveling underneath the sea surface can be even warmer than temperatures showing up at the surface. This is illustrated by the image below indicating that on August 16, 2015, warm water emerged at the sea surface near Svalbard with temperatures as high as 14.9°C or 58.7°F, a 9.5°C or 17.1°F anomaly.

There still is about a month to go before sea ice can be expected to reach its minimum, at around half September 2015, while sea currents will continue to carry warmer water into the Arctic Ocean for months to come.

The situation is dire and calls for comprehensive and effective action, as discussed in the Climate Plan. 

Thick sea ice is virtually absent compared to the situation in the year 2012 around this time of year, as illustrated by...
Posted by Sam Carana on Tuesday, August 18, 2015

More than 2.5m Sea Level Rise by 2040?

More than 2.5m Sea Level Rise by 2040?

flood glaciers ice linear melt ocean polynomial rise sea level storm surge temperature trend water waves

Unknown 7/29/2014 Add Comment

A warming period more than 400,000 years ago pushed the Greenland ice sheet past its stability threshold (which may have been no more than several degrees above pre-industrial temperatures). This resulted in a nearly complete deglaciation of southern Greenland, raising global sea levels some 4.5-6 meters, found a recent study by Reyes et al. Due to melting elsewhere, global mean sea level then was 6 to 13 metres above the present level. Indeed, melting of the entire West Antarctic Ice Sheet can add a further 6-meter rise in sea levels. If the East Antarctic Ice Sheet (EAIS) were to melt as well, sea levels would rise by around 70 metres.

Sea level is now rising by 3.1mm (0.122 inch) per year. Much of this rise is due to rising temperatures, but there are also other factors. One quarter of the rise results from groundwater depletion, while run off from melting ice and glaciers adds another quarter and the remainder is attributed to thermal expansion of sea water. Furthermore, as temperatures rise, feedbacks start to kick in, e.g. the kinetic energy from stronger waves and more intense storms can speed things up.

Clearly, a rapid multi-meter rise would be devastating as it would flood many coastal cities, as well as much of the land now used to grow food. By how much have sea levels been rising recently and how fast can they be expected to rise in the near future?

NASA image, data by the JPL PODAAC, in support of the NASA's MEaSUREs program.

Sea levels have risen by some 60 mm over the past 20 years, as above NASA image shows, which has a linear trendline added. The question is whether a linear trendline is the most appropriate trendline, given that it suggests that a similar rise could be expected over the next 20 years. A polynomial trendline appears to fit the data better, as the animation below shows.

Such a polynomial trendline, however, points at a similar rise (of some 50 mm) in just four years time, with an even more steeper rise to follow, as illustrated by the image below.

And indeed, such a rise doesn't slow down there. A polynomial trendline applied to the data points at a sea level rise of more than 2.5 m (8.2 ft) by the year 2040.

The image below gives an idea of what a sea level rise of six feet (1.829 m) would do to the City of New York. Of course, this is only the sea level rise. Storm surge would come on top of this, as discussed at Ten Dangers of Global Warming.

So, what would be more appropriate, to expect sea levels to continue to rise in a linear way, or to take into account feedbacks that could speed things up? Where such feedbacks could lead to is illustrated by the image below.

[ from: How many deaths could result from failure to act on climate change? click on image to enlarge ]

This calls for comprehensive and effective action, as discussed at the Climate Plan blog.


References

- South Greenland ice-sheet collapse during Marine Isotope Stage 11, Reyes et al. (2014)
http://www.nature.com/nature/journal/v510/n7506/full/nature13456.html

- Nonsustainable groundwater sustaining irrigation: A global assessment, Yoshihide Wada et al. (2012)
http://onlinelibrary.wiley.com/doi/10.1029/2011WR010562/abstract

- Groundwater Depletion Linked to Rising Sea Levels
http://www.waterworld.com/articles/2010/11/groundwater-depletion-linked-to-rising.html

- Assessment of the Jason-2 Extension to the TOPEX/Poseidon, Jason-1 Sea-Surface Height Time Series for Global Mean Sea Level Monitoring, Beckley et al. (2010)
http://www.tandfonline.com/doi/abs/10.1080/01490419.2010.491029

- Feedbacks in the Arctic
http://climateplan.blogspot.com/p/feedbacks.html

- How many deaths could result from failure to act on climate change? (2014)
http://arctic-news.blogspot.com/2014/05/how-many-deaths-could-result-from-failure-to-act-on-climate-change.html

Post by Sam Carana.

What's wrong with the weather?

What's wrong with the weather?

anomaly Arctic jet stream methane ocean SST temperature water weather

Unknown 7/02/2014 Add Comment

Above map shows temperatures in NewFoundland and Labrador close to 30°C (86°F), compared to temperatures in Albuquerque, New Mexico of only 20°C (68°F), while temperatures seem to be even lower in Mexico City. What's happening with the weather?

Jet Streams are changing

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.

As the Arctic is warming even faster than the Equator, the falling temperature difference between the two reduces the speed at which warm air is moving from the Equator to the North Pole. This in turn slows the speed at which the jet streams are circumnavigating the globe on the Northern hemisphere and it is deforming the jet streams in other ways as well.

[ NOAA image ]

As above image shows, the polar jet stream is typically located at about 60°N and the subtropical jet stream at about 30°N. The polar jet stream's altitude typically is near the 250 hPa pressure level, or 7 to 12 kilometres (4.3 to 7.5 mi) above sea level, while the weaker subtropical jet stream's altitude is higher, between 10 and 16 kilometres (6.2 and 9.9 mi) above sea level.

NOAA image

The polar jet stream used to travel 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. This fast and relatively straight jet stream kept climate zones well apart. Accordingly, the Northern Temperate Zone used to experience only mild differences between summer and winter weather, rather than the extremely hot or cold temperatures that we're increasingly experiencing now.

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

Loss of snow and ice cover in the north is accelerating warming in the Arctic. This is decreasing the difference in temperature between the Arctic and the Northern Temperate Zone, in turn causing the polar jet to slow down and become more wavy, i.e. with larger loops, as illustrated by the animation below.

Imagine a river that at first rapidly runs down a narrow and straight path when its waters fall down from the top of a high mountain. Once that river flows through flat land, though, it becomes slow and curvy.

Similarly, the polar jet stream is now circumnavigating the globe at slower speed and along a wavier tracks. Its waves are now more elongated, more stretched out vertically, making that cold air can move more easily down from the Arctic, e.g. through the middle of North America, as illustrated by the animation below.

At the same time, warm air can move up more easily from the South into the Arctic. This is creating huge temperature anomalies in many places, as also illustrated by the animation below.

[ This animation is a 1.4MB file that may take some time to fully load ]

                Diagram of Doom, Sam Carana

These changes to polar jet stream constitute a self-reinforcing feedback that is further accelerating warming in the Arctic. As the jet stream slows down and its waves become more elongated, cold air can leave the Arctic more easily and descend deep into the Northern Temperate Zone. Conversily, more warm air can at the same time move north into the Arctic. The result is a warmer Arctic.

This '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.

This feedback is pictured in the image below as feedback #10.

Diagram of Doom - see Feedbacks in the Arctic for links

Arctic sea ice in steep descent

Global warming and the numerous feedbacks have a devastating impact on the sea ice, which is currently showing an almost vertical fall in extent, as illustrated by the image below.

Oceans are turning red

Arctic sea ice is also under threat from very warm waters. As the image below illustrates, oceans are turning red around the globe.

The image below shows that where the sea ice disappears, sea surface temperature anomalies as high as 8°C and higher show up.

Comprehensive and Effective Climate Action

The situation is dire, as huge amounts of methane are contained in sediments underneath the seafloor of the Arctic Ocean. Loss of sea ice means that huge amounts of heat that was previously reflected back into space will be absorbed by the Arctic Ocean. Furthermore, heat that previously went into melting the ice will also be absorbed by the water. Comprehensive and effective action is needed, as discussed at the Climate Plan blog.

Post by Sam Carana.

How many deaths could result from failure to act on climate change?

How many deaths could result from failure to act on climate change?

casualty climate change death drought famine food heatstroke heatwave pollution smoke water wildfires

Unknown 5/31/2014 Add Comment

A recent OECD study concludes that outdoor air pollution is killing more than 3.5 million people a year globally. The OECD estimates that people in its 34 Member countries would be willing to pay USD 1.7 trillion to avoid deaths caused by air pollution. Road transport is likely responsible for about half.

A 2012 report by DARA calculated that 5 million people were dying each year from climate change and carbon economies, mostly from indoor smoke and (outdoor) air pollution.

Back in 2012, a Reuters report calculated that this could add up to a total number of 100 million deaths over the coming two decades. This suggests, however, that failure to act on climate change will not cause even more deaths due to other causes.

Indeed, failure to act on climate change could result in many more deaths due to other causes, in particular food shortages. As temperatures rise, ever more extreme weather events can be expected, such as flooding, heatwaves, wildfires, droughts, and subsequent crop loss, famine, disease, heat-stroke, etc.

So, while currently most deaths are caused by indoor smoke and outdoor air pollution, in case of a failure to act on climate change the number of deaths can be expected to rise most rapidly among people hit by famine, fresh water shortages, as well as wars over food, water, etc.

How high could figures rise? Below is an update of an image from the earlier post Arctic Methane Impact with a scale in both Celsius and Fahrenheit added on the right, illustrating the danger that temperature will rise to intolerable levels if little or no action is taken on climate change. The inset shows projected global number of annual climate-related deaths for these two scenarios, i.e. no action and little action, and also shows a third scenario of comprehensive and effective action that would instead bring temperature rise under control.

[ click on image to enlarge ]

For further details on a comprehensive and effective climate plan, see the ClimatePlan blog.

Post by Sam Carana.

Feedbacks in the Arctic

Feedbacks in the Arctic

Arctic feedbacks methane ocean rise sea ice temperature water

Unknown 3/20/2014 Add Comment

This is more a climate report than a weather report; yet, the extreme weather that did hit the U.K. recently and that is forecast to hit large parts of North America next week may make more people realize that action is needed now. So, please share!

At the moment, a large part of Russia is experiencing temperature anomalies at the highest end of the scale, i.e. more than 36°F (20°C) warmer than average past records.

Above image shows the situation as at March 20, 2014. The image below is a forecast for March 22, 2014.

Over the past year, average temperatures over the Arctic Ocean have been much higher than they used to be, as illustrated by the NOAA image below.

Warming in the Arctic is accelerating, in part due to a number of feedbacks such as extreme weather. Temperatures over the Arctic Ocean are expected to rise even further next week. The Arctic as a whole is expected to reach average anomalies as high as 5.3°C next week, while many areas over the Arctic Ocean are expected to be hit by even higher anomalies, as the image below shows.

 [ click on image to enlarge ]

Above image also shows that, at the same time, very low temperatures - with anomalies at the low end of the scale - are expected to hit a large part of North America. The image below shows what temperatures can be expected on March 26, 2014, 12:00 UTC.

As above image illustrates, temperatures over a large part of North America can be expected to be hardly higher than temperatures over the Arctic Ocean mid next week. It is this very difference between high altitude temperatures and lower altitude temperatures that drives the Jet Stream. In the absence of much difference, changes to the Jet Stream are making it easier for cold air to move out of the Arctic and for warm air from lower latitudes to move in. The Polar Vortex is similarly affected, as illustrated by the image below.

At lower altitude, the highest wind speed detected on the image below was 94 km/h (green marker). Strong winds brought a lot of rain from the Atlantic Ocean to the U.K., as has been the case for some time.

[ click on image to enlarge ]

The result is more extreme weather, which can translate into more intense storms, heatwaves, droughts, wildfires and further havoc. Importantly, storms across the Arctic Ocean and higher wind speeds along the edges of Greenland can break up the ice and speed up its exit from the Arctic Ocean. The Naval Research Laboratory animation below shows strong winds pushing the sea ice around and speeding up its exit along the edges of Greenland. 

Despite the cold weather that has hit large parts of North America over the past few months, the water off the coast of North America has not cooled, as illustrated by the image below. The blue and lilac colored areas are in part the result of exit currents carrying cold water out of the Arctic Ocean more rapidly, while the Gulf Stream continues to carry warmer water (brown and red colored areas) into the Arctic Ocean. 

[ Sea Surface Temperatures (SST) - click on image to enlarge ]

The Arctic is especially vulnerable to warming, due to a number of circumstances, including:
- Gulf Stream carrying warmer water into the Arctic Ocean;
- Arctic snow and ice cover is at the verge of collapse;
- Methane is present in large quantities under the seafloor of the Arctic Ocean.
These circumstances and the combined impact of feedbacks such as extreme weather make that, on top of global warming, the Arctic is hit by a second, addtional kind of warming, i.e. accelerating warming in the Arctic.

The joint impact of feedbacks is becoming stronger, as temperatures keep rising in the Arctic and with continued demise of the snow and ice cover. So, let's start with feedback #1, i.e. that, as snow and ice cover decline further, an ever larger part of the sunlight will be absorbed by the Arctic Ocean, rather than to (a) be reflected back into space or (b) be consumed in the process of transforming ice into water. This first feedback will then be amplified by further feedbacks such as storms that can more easily develop in open water. And, as the weather becomes more extreme, stronger storms and heatwaves can be expected to hit the Arctic Ocean, causing further demise of the sea ice, resulting in more heat being absorbed by the Arctic Ocean. Thus, feedbacks can amplify each other, causing warming in the Arctic to accelerate even further. 

One of the most dangerous feedbacks is that, as the Arctic Ocean warms up further and as the Gulf Stream carries ever warmer water into the Arctic Ocean, methane can erupt from the seafloor of the Arctic Ocean in large quantities. Methane eruptions from the seafloor of the Arctic Ocean have become especially noticable over the past half year. The big danger is that this will develop into a third kind of warming, runaway global warming. 

Large amounts of methane are still entering the atmosphere over the Arctic Ocean, which contains very little hydroxyl to start with, so large abrupt releases will deplete the little hydroxyl that is there much faster than elsewhere. Furthermore, the methane will initially be highly concentrated in the atmosphere over the Arctic Ocean, and where the methane does move out of the Arctic, it could warm up the water along the track of the Gulf Stream, causing even warmer water to enter the Arctic Ocean. For years after its release, the methane will act as a powerful greenhouse gas. Unlike the albedo changes, which have the highest impact at the June Solstice when the amount of solar radiation received by the Arctic is higher than anywhere else on Earth, methane prevents heat from radiating out into space throughout the year. 

The interactive diagram below gives an overview of these three kinds of warming and the numerous feedbacks that are accelerating warming in the Arctic, from the earlier post The Biggest Story of 2013.

Hover over each kind of warming and feedback to view more details, click to go to page with further background 

In conclusion, the situation is dire and calls for comprehensive and effective action, as described at the Climate Plan blog.




Related

- The Biggest Story of 2013
http://arctic-news.blogspot.com/2013/12/the-biggest-story-of-2013.html

- Climate Plan
http://climateplan.blogspot.com

- Changes to Polar Vortex affect mile-deep ocean circulation patterns
http://arctic-news.blogspot.com/2012/09/changes-to-polar-vortex-affect-mile-deep-ocean-circulation-patterns.html

- Diagram of Doom
http://arctic-news.blogspot.com/2012/08/diagram-of-doom.html

- Polar Jet Stream appears hugely deformed
http://arctic-news.blogspot.com/2012/12/polar-jet-stream-appears-hugely-deformed.html

- Methane Levels going through the Roof
http://arctic-news.blogspot.com/2013/11/methane-levels-going-through-the-roof.html

- Ocean heat: Four Hiroshima bombs a second: how we imagine climate change
http://arctic-news.blogspot.com/2013/08/four-hiroshima-bombs-second-how-we-imagine-climate-change.html

- (Three kinds of) Warming in the Arctic
http://arctic-news.blogspot.com/p/warming-in-arctic.html

- Methane hydrates
http://methane-hydrates.blogspot.com/2013/04/methane-hydrates.html

Feedbacks

1. Snow and ice decline causing more sunlight to be absorbed by the Arctic Ocean
   http://arctic-news.blogspot.com/2012/07/albedo-change-in-arctic.html
2. Methane releases warming up Arctic air
   http://arctic-news.blogspot.com/2013/11/methane-levels-going-through-the-roof.html
3. As sea ice decline weakens vertical currents, seabed warms
   http://arctic-news.blogspot.com/2012/09/arctic-sea-ice-loss-is-effectively-doubling-mankinds-contribution-to-global-warming.html
4. Storms cause vertical mixing of water
   http://arctic-news.blogspot.com/2012/07/arctic-waters-are-heating-up.html
5. Accelerated Arctic warming causes storms that push cold air of the Arctic
   http://arctic-news.blogspot.com/2012/08/diagram-of-doom.html
6. Extreme weather causing storms that push away sea ice
   http://arctic-news.blogspot.com/2012/04/supplementary-evidence-by-prof-peter.html
7. Extreme weather causing storms that create higher waves, breaking up the sea ice
   http://arctic-news.blogspot.com/2012/08/huge-cyclone-batters-arctic-sea-ice.html
8. Storms creating more wavy waters that absorb more sunlight
   http://arctic-news.blogspot.com/2012/08/diagram-of-doom.html
9. Extreme weather causing fires, etc.
   http://arctic-news.blogspot.com/2012/07/how-extreme-will-it-get.html
10. Weaker polar vortex and jet stream let cold air move out of Arctic
    http://arctic-news.blogspot.com/2012/08/opening-further-doorways-to-doom.html
11. Extreme weather causing warmer waters
    http://arctic-news.blogspot.com/2013/12/the-biggest-story-of-2013.html
12. Snow and ice decline cause seismic activity that destabilizes hydrates
    http://arctic-news.blogspot.com/2013/09/methane-release-caused-by-earthquakes.html
13. Methane releases prevent sea ice from forming
    http://arctic-news.blogspot.com/2013/12/methane-emerges-from-warmer-areas.html

Post by Sam Carana.