Feedbacks in the Arctic

created by Sam Carana, part of AGU 2011 poster
The dangerous situation in the Arctic is depicted by the image on the right, showing that the Arctic is hit by three major developments, i.e. three kinds of warming:
- Global Warming
- Accelerated warming in the Arctic
- Runaway Global Warming

The blue rectangles depict events that feed these developments, in some cases over a number of other events. 

Where developments and events feed each other, these interactions are depicted by lines with the direction of the feed indicated by the arrow.

Such feeds can turn into self-reinforcing feedback loops, i.e. a development or event that feeds back into itself, either directly or over a number of other events. 

Two such self-reinforcing feedback loops are depicted in above image and they are also highlighted in the image on the right. 

Feedback loop #1 occurs where sea ice loss results in albedo changes that accelerate warming in the Arctic, closing the loop by causing further sea ice loss. 

Feedback loop #2 occurs where accelerated Arctic warming weakens methane stores, resulting in methane releases that further accelerate warming in the Arctic. 

In both cases, accelerated warming in the Arctic feeds events that in turn feed other events, eventually causing further acceleration of warming in the Arctic. 

There are further self-reinforcing feedback loops. The image below also pictures how another feedback loop occurs as accelerated warming in the Arctic alters the jet stream, resulting in more extreme weather, in particular heatwaves, that cause wildfires. These wildfires cause all kinds of emissions, including carbon dioxide, dust, soot, volatile organic compounds, methane and other ozone precursors. The greenhouse gases accelerate warming, while aerosols can have a particularly strong impact in the Arctic when they settle on land, snow and ice and cause albedo changes that further accelerate warming in the Arctic. Incomplete burning results in carbon monoxide, which depletes hydroxyl that could otherwise have broken down methane.

In addition, there can also interactions between feedback loops. As an example, changes to the jet stream can cause heatwaves that will speed up snow and ice decline.

Above images show how such feedbacks cause further acceleration of warming in the Arctic, eventually spiraling out of control and escalating into a third kind of warming, i.e. runaway global warming.

In above image, three red arrows depict three major developments, i.e. three kinds of warming, with some feedbacks highlighted in yellow. The image below depicts numerous such feedbacks. 

Further details about each of these feedbacks are given at the end of this post. Without effective and comprehensive action, these feedbacks will lead to runaway warming, i.e. abrupt climate change causing mass death and destruction, and resulting in extinction at massive scale, as depicted in the image below and as described in this post.

The threat that this constitutes to security of supply of food and fresh water is further described in this post and this post, each also pointing at the need for a comprehensive and effective action plan. Without such action, as said, the above three kinds of warming are threatening to lead to a fourth development, i.e. near-term mass extinction of many species including humans, as above image shows. Action recommended as part of the Climate Plan is described at the Action page.

Feedbacks in the Arctic

1. Albedo loss due to snow and ice retreat and further snow and ice decline
Albedo loss can occur due to several forms of sea ice decline, i.e. when sea ice retreats, when warming changes the texture of the ice, and when meltwater pools emerge on top of the ice. Global warming is accelerated in the Arctic, causing snow and ice decline that results in albedo loss and thus more sunlight being absorbed, further accelerating warming in the Arctic, in a self-reinforcing cycle. Note that more sunlight gets absorbed on by the Arctic Ocean and on land, causing permafrost to melt to greater depth. 

2. Methane heat trapping
Methane releases are warming up the atmosphere over the Arctic, trapping heat. 

3. Vertical currents weaken
As sea ice decline weakens vertical currents in the Arctic Ocean, the seabed warms up faster. 

4. Storms and heat waves causing more vertical mixing of water
This can cause warm water from the top layer of open waters to reach the seabed. 

5. Storms and heat waves accelerating Arctic warming
Accelerated Arctic warming causes stronger storms, bring more warm air into the Arctic and pushing more cold air out of the Arctic. Furthermore, accelerated warming causes stronger heat waves that cause more melting of snow and ice. This accelerates warming in the Arctic and constitutes a self-reinforcing cycle. 

6. More storms, heat waves and evaporation creating more open water, clouds and precipitation 
Extreme weather events such as storms can push sea ice out of the Arctic Ocean into the Atlantic Ocean. This creates more open waters where storms can develop more easily, as there will be more opportunity for evaporation. The resulting precipitation can make the sea ice more slushy, in a self-reinforcing cycle. Also, more heat can be trapped underneath clouds, and this can occur all year long, as opposed to the summer-only effect of more sunlight getting reflected back into space by such clouds. (see also feedback # 27.). 

7. Waves
Extreme weather cause winds and higher waves that degrade sea ice, breaking the ice and causing 
it to melt faster, resulting in more open water that further contributes to snow and ice decline. Waves break up sea ice into numerous pieces that act as sails, catching the wind and moving more easily with the winds, possibly all the way out of the Arctic Ocean.  

8. Albedo loss due to waves
Waves causing more wavy waters, and more wavy waters absorb more sunlight.

9. Extreme weather causing fires, dust, growth of microbes and further sources of emissions 
Such emissions will further contribute to global warming, while such pollution can also settle on snow and ice, resulting in greater absorption of sunlight, particularly in the Arctic. 

10. Open Doors
Accelerated Arctic warming changes the polar vortex and jet stream, making it easier for warm air to move into the Arctic and for cold air to move out of the Arctic, in turn further decreasing the temperature difference between the Equator and the North Pole, in a self-reinforcing feedback loop. As Sam Carana says: "It's like leaving the fridge door open." 

11. Warmer waters
Warmer Arctic waters due to Gulf Stream warming, due to heatwaves and due to warmer rivers that end up in the Arctic Ocean. This will warm up the seabed of the Arctic Ocean. 

12. Seismic activity
Retreat of ice and snow cover comes with isostatic rebound, which can trigger underwater earthquakes, shockwaves and landslides, in turn destabilizing methane hydrates. 

13. Less sea ice forming 
Sea ice can be prevented from forming, due to kinetic energy (bubbling) of methane as it rises in the water and enters the atmosphere 

14. Latent heat loss
Where ice disappears, the heat will no longer go into the process of melting the ice, and the heat will instead go into increasing water temperatures. 

15. Warmer Gulf Stream
The Gulf Stream warms due to emissions, and this can be made worse by extreme weather, resulting in even warmer water being carried by the Gulf Stream into the Arctic Ocean, thus further accelerating warming in the Arctic and the extreme weather events that this contributes to. 

16. Seafloor warming
As the seafloor of the Arctic Ocean warms up, heat can penetrate sediments, causing destabilization, resulting in methane releases

17. Methane expansion
As methane escapes from hydrates, it expands to 160 times its earlier volume. The shock resulting from such expansion can cause further hydrate destabilization.  

18. Heat waves causing snow and ice decline 
Extreme weather causing longer and more intense heat waves resulting in greater snow and ice decline

19. Changes to the polar vortex and jet streams causing extreme weather events
Extreme weather events can trigger further feedbacks, including:
- storms causing greater vertical mixing of water (feedback #4)
- storms and heatwaves accelerating Arctic warming, in turn causing further extreme weather (feedback #5)
- storms and heat waves increasing humidity in the Arctic (feedback #6)
- strong waves (feedback #7)
- heat waves triggering wildfires (feedback #9)
- jet stream reaching high latitudes, moving warm air into the Arctic (feedback #10)
- heat waves causing Arctic seabed warming (feedback #11)
- heat waves causing snow and ice decline (feedback #18)

20. Seismic activity triggers earthquakes and landslides
Submarine volcano eruptions, earthquakes and associated shockwaves can in turn trigger further earthquakes, as well as submarine landslides, especially along fault lines that separate tectonic plates. 

21. Temperature swings causing destabilization
Methane is present in the Greenland ice sheet in the form of hydrates and free gas. Huge temperature swings can hit areas over Greenland over the course of a few days, causing the ice to expand and contract, thus causing difference in pressure as well as temperature. The combined shock of wild pressure and temperature swings is causing movement, friction and fractures in the ice, and this enables methane to rise to the surface and enter the atmosphere.

22. More plankton
A study by Park et al, May 12, 2015, concludes that the biogeophysical effect of future phytoplankton changes amplifies Arctic warming by 20%. The warming-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton warms the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic warming further.

23. Emissivity change
Feldman et al, Nov 18, 2014, found that open oceans are much less efficient than sea ice when it comes to emitting in the far-infrared region of the spectrum. The research team used a computer model that showed that open oceans hold more far-infrared energy than sea ice, resulting in warmer oceans, melting sea ice, and a 2°C rise in the polar climate after 25-year run.

24. Rivers warming the Arctic Ocean 
Heatwaves over North America and Siberia can cause huge amouynts of warm water to enter the Arctic Ocean.

25. Water vapor and clouds
As oceans warm, the atmosphere can be expected to carry more water vapor. This conclusion is supported by studies such as this one.  Since water vapor is a potent greenhouse gas, more water vapor in the atmosphere will contribute to global warming. Clouds can on the one hand reflect more sunlight back into space, but on the other hand they can also trap heat and reflect heat back to Earth that would otherwise be radiated out into space. Studies such as by Dessler and by Sherwood et al. conclude that more clouds are likely to contribute to global warming.

26. Salinity
Evaporation rates are higher over fresh water surfaces than over saline water surfaces. This, in combination with the higher temperature of river water flowing into the Arctic Ocean, will lead to more evaporation and thus more rain, which in turn results in warm rainwater pools on top of the sea ice, speeding up its demise.

27. More open water in the Arctic contributes to more severe storms
With more water vapor in the atmosphere and with more extreme weather events, storms can be expected to strike with greater intensity. This situation gets even worse as the Arctic Ocean loses its sea ice, with the additional open water adding to the water vapor in the atmosphere. This gives more opportunity for plumes above the anvils of severe storms to bring water vapor up into the stratosphere, contributing to the formation of cirrus clouds that trap a lot of heat that would otherwise be radiated away, from Earth into space.

28. Cold freshwater lid on the North Atlantic
Melting of the Greenland ice sheet and the permafrost on North America results in meltwater being pushed by sea currents into the North Atlantic, where it accumulates and forms a cold freshwater lid on top of the water. This results in less evaporation and transfer of heat from the ocean to the atmosphere, and more ocean heat being carried by the Gulf Stream below the sea surface into the Arctic Ocean.
This is a self-reinforcing feedback loop, as described in the post at:

1 comment:

  1. The Climate Plan calls for comprehensive action through multiple lines of action implemented across the world and in parallel, through effective policies such as local feebates. The Climate Plan calls for a global commitment to act, combined with implementation that is preferably local. In other words, while the Climate Plan calls for a global commitment to take comprehensive and effective action to reduce the danger of catastrophic climate change, and while it recommends specific policies and approaches how best to achieve this, it invites local communities to decide what each works best for them, provided they do indeed make the progress necessary to reach agreed targets. This makes that the Climate Plan optimizes flexibility for local communities and optimizes local job and investment opportunities.

    Click for more on multiple lines of action, on recommended policies, and on the advantages of feebates.