Showing posts with label accelerated. Show all posts
Showing posts with label accelerated. Show all posts

Friday, October 13, 2023

Temperature rise - September 2023 and beyond

The above image, adapted from NASA and the image below, adapted from Climate Reanalyzer and using the same baseline, illustrate the September 2023 temperature anomaly.


September 2023 was the month with the highest temperature anomaly on record. What contributed to this?

El Niño
 

The temperature rose about 0.5°C from November 2022 to March 2023, and this occurred at a time when we were not even in an El Niño yet, as illustrated by the above image, from an earlier post. Below is an updated image, from January 1950 to September 2023, adapted from NOAA

[ click on images to enlarge ]
[ click on images to enlarge ]
The current El Niño is still strengthening, as illustrated by the image on the right, adapted from IRI.

Further contributors

There are further reasons why the temperature can be expected to keep rising beyond September 2023.

The number of sunspots has been higher than predicted and looks set to keep rising above predicted levels until July 2025, as discussed here.

The eruption of the submarine volcano near Tonga in January 2022 caused a lot of water vapor to reach high up into the atmosphere and this may still contribute to the temperature rise, as discussed here.

Aerosols that have a cooling effect, such as dust and sulfates (SO₄), are also important. As fossil fuel is burned, sulfates are co-emitted. Since they pollute the air, measures have been taken and are being taken to reduce them, e.g. in shipping, and this has pushed up the temperature rise. Meanwhile, cooling aerosols such as sulfates are still high. As illustrated by the image below, adapted from nullschool.net, SO₄ was as high as 8.621 τ at the green circle on October 6, 2023, at 07:00 UTC. In future, SO₄ could fall dramatically, e.g. in case of a sudden economic collapse, reducing the aerosol masking effect rapidly and abruptly causing a substantial rise in temperature.


After little change in the Antarctic sea ice extent graph for decades, extent loss was dramatic in 2022 and even more dramatic in 2023, as less and less sunlight was getting reflected back into space and instead was getting absorbed by the water of the Southern Ocean, as illustrated by the image below, adapted from NSIDC.
Sea ice retreat comes with loss of albedo, i.e. loss of the amount of sunlight reflected back into space, resulting in more heat getting absorbed in the Southern Ocean, making it a self-reinforcing feedback loop. Clouds constitute another self-reinforcing feedback loop; a warmer Southern Ocean comes with fewer bright clouds, further reducing albedo, as discussed here and here. For decades, there still were many lower clouds over the Southern Ocean, reflecting much sunlight back into space, but these lower clouds have been decreasing over time, further speeding up the amount of sunlight getting absorbed by the water of the Southern Ocean, and this 'pattern effect' could make a huge difference globally, as a recent study points out. Emissivity is a further factor; open oceans are less efficient than sea ice when it comes to emitting in the far-infrared region of the spectrum (feedback #23 on the feedbacks page). 



The above image was created by Zach Labe with NSIDC data (Arctic + Antarctic) for each year from 1979 to 2023 (satellite-era; NSIDC, DMSP SSM/I-SSMIS). The image illustrates that global sea ice extent  recently reached the largest anomaly in the satellite record. Anomalies are calculated using a 5-day running mean from a climatological baseline of 1981-2010. 2016 is shown with a yellow line. 2023 is shown using a red line (updated 10/16/2023).

In the video below, Paul Beckwith discusses the importance of loss of sea ice at around -60° (South).


As said, there are many factors behind the temperature increase around latitude -60° (South). As Paul mentions, this latitude receives a lot of sunlight around the year. Therefore, it is not surprising that, as oceans continue to heat up, there is huge loss of sea ice at this latitude, as well as loss of lower clouds, while open oceans are additionally less efficient than sea ice when it comes to emitting in the far-infrared region of the spectrum. The image below, adapted from NASA, shows a white band around -60° (South), indicating that the Southern Ocean has long been colder there than elsewhere, but has recently started to catch up with the global temperature rise.



The above image also illustrates that anomalies are highest in the Arctic, narrowing the temperature difference between the Arctic and the Tropics, with the air flow slowing down accordingly. 

[ image adapted from Copernicus ]
This in turn changes the Jet Stream and the Polar Vortex, resulting in blocking patterns that can, in combination with rising temperatures, strongly increase the frequency, intensity, duration and area coverage of extreme weather events such as storms and lightning, heatwaves and forest fires.

Forest fires in Canada have been releasing massive amounts of emissions that push up the temperature, including greenhouse gases such as carbon dioxide, warming aerosols such as black carbon & brown carbon and NMVOC (non-methane volatile organic carbon) and carbon monoxide that reduce the availability of hydroxyl, resulting in more methane and ozone in the atmosphere. 

[ NH sea surface temperature anomaly ]
At the same time, slowing down of the Atlantic Meridional Ocean Current (AMOC) can result in more ocean heat accumulating at the surface of the North Atlantic, as illustrated by the image on the right, from an earlier post.

As temperatures rise, increased meltwater runoff from Greenland and more icebergs moving south, in combination with stronger ocean stratification and stronger storms over the North Atlantic, can also cause a freshwater lid to form at the surface of North Atlantic that can at times enable a lot of hot water to get pushed abruptly underneath this lid toward the Arctic Ocean. The danger is that more heat will reach the seafloor and destabilize methane hydrates contained in sediments at the seafloor of the Arctic ocean. 

Ominously, very high methane levels continue to be recorded at Barrow, Alaska, as illustrated by the image below, adapted from NOAA.

The next few months will be critical as Arctic sea ice is sealing off the Arctic Ocean from the atmosphere, trapping heat underneath the ice and making it harder for ocean heat to get transferred from the Arctic Ocean to the atmosphere above the Arctic. Furthermore, sea ice is very thin, reducing the latent heat buffer that could otherwise have consumed ocean heat. 

The next danger is that the thin Arctic sea ice will rapidly retreat early next year as a warming Arctic Ocean will transfer more heat to the atmosphere over the Arctic, resulting in more rain and more clouds in the atmosphere over the Arctic, speeding up sea ice loss and further pushing up the temperature rise over the Arctic, as discussed at the feedbacks page, which also discusses how less Arctic sea ice can push up temperatures through the emissivity feedback. As temperatures rise over the Arctic, permafrost on land also threatens to thaw faster, threatening to cause huge releases of greenhouse gases, including carbon dioxide, methane and nitrous oxide. 


Meanwhile, emissions of greenhouse gases keep rising, further pushing up the temperature, as illustrated by the image below, from an earlier post.
  
Global energy-related greenhouse gas emissions 2000-2022, adapted from EIA ]
In the video below, Guy McPherson describes how temperature rise, loss of habitat and meltdown of nuclear power facilities each could result in rapid extinction of humans and many other species.


There are numerous further feedbacks that can accelerate the temperature rise and tipping points that can get crossed and cause even more abrupt rise of the temperature. One of these is the clouds tipping point that in itself can cause a temperature rise of 8°C, as discussed here.

Further feedbacks are also discussed at the Extinction page.  One further feedback is water vapor. A warmer atmosphere holds more water vapor, at a rate of 7% for each Degree Celsius the temperature rises. As temperatures keep rising, ever more water vapor will be sucked up by the atmosphere. This will also cause more droughts, reducing the ability of land to sustain vegetation and provide soil cooling through shading and through evaporation and formation of lower clouds, as discussed here. More water vapor in the atmosphere will also speed up the temperature rise because water vapor is a potent greenhouse gas.

The fact that such tipping points and feedbacks occur as greenhouse gas levels reach certain levels and as the temperature rise makes it critical to assess how fast greenhouse gas levels could rise and by how much the temperature has already risen. 

NASA data up through September 2023

The image below, adapted from NASA, shows that the September 2023 NASA Land+Ocean temperature was 1.78°C higher than it was in September 1923. The anomaly is 1.74°C when compared to a base centered around the year 1900 (1885-1915). The 1.74°C anomaly can be adjusted by 0.99°C to reflect a pre-industrial base, air temperature and higher polar anomalies (as shown in the box on the bottom right of the image), adding up to a potential anomaly of 2.73°C. 

[ click on images to enlarge ]
Indeed, earlier analysis such as discussed here, points out that the temperature may already have risen by more than 2°C (compared to pre-industrial) in 2015, when politicians pledged at the Paris Agreement to take action to combat the temperature rise to prevent this from happening. 

Blue: Polynomial trend based on Jan.1880-Sep.2023 data. 
Magenta: Polynomial trend based on Jan.2010-Sep.2023 data.
The above image is created with NASA Land+Ocean monthly mean global temperature anomalies vs 1885-1915, adjusted by 0.99°C to reflect ocean air temperature, higher polar anomalies and a pre-industrial base, and has trends added.  

Alarms bells have been sounding loud and clear for a long time, as discussed in posts such as this one, warning that the temperature could rise by more than 3°C by 2026. The above magenta graph shows how this could occur as early as next year (end 2024).

[ image from earlier post ]
[ image from the Extinction page ]
The above image illustrates the latent heat tipping point - estimated to correspond with a sea surface temperature anomaly of 1°C above the long term average (1901-1930 on the above image) - to get crossed and the seafloor methane tipping point - estimated to correspond with a sea surface temperature anomaly of 1.35°C - to get reached, as discussed in earlier posts such as this one, .

A Blue Ocean Event could occur as the latent heat and seafloor methane tipping points get crossed, and the ocean temperature keeps rising, as huge amounts of methane get released in the Arctic, as ever more heat keeps reaching and destabilizing methane hydrates contained in sediments at the seafloor of the Arctic Ocean, as discussed in many earlier posts such as this one.

Seafloor methane is one of many elements that could jointly cause a temperature rise of over 10°C, in the process causing the clouds tipping point to get crossed that can push up the temperature rise by a further 8°C, as illustrated by the image on the right, from the extinction page.

Conclusion

The precautionary principle should prevail and the looming dangers should prompt people into demanding comprehensive and effective action to reduce the damage and to improve the situation. 

To combat rising temperatures, a transformation of society should be undertaken, along the lines of this 2022 post in combination with a declaration of a climate emergency.


Links

• NASA - global maps

• NOAA - ENSO and Temperature bars

• The International Research Institute for Climate and Society, Columbia University Climate School
https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table

• Nullschool.net

• NSIDC - sea ice graph

• Zach Labe - Global sea ice - extent, concentration, etc.

• NASA - zonal means
https://data.giss.nasa.gov/gistemp/zonal_means

• Copernicus - Northern Hemisphere wildfires: A summer of extremes
https://atmosphere.copernicus.eu/northern-hemisphere-wildfires-summer-extremes

• NOAA - Barrow Atmospheric Baseline Observatory, United States
https://gml.noaa.gov/dv/iadv/graph.php?code=BRW&program=ccgg&type=ts

• Paul Beckwith - Accelerated Global Warming from Antarctic Sea Ice Collapse: Albedo, Latitude, Snow Cover on Ice…
https://www.youtube.com/watch?v=-5P1W4TrczQ

• Guy McPherson - College of Complexes Presentation (with Improved Audio) 

• NASA custom plots
https://data.giss.nasa.gov/gistemp/graphs_v4/customize.html

• Transforming Society



Thursday, June 25, 2015

Accelerated Warming in the Arctic


Warming in the Arctic is accelerating. On June 25, 2015, high temperatures hit North America. Temperatures as high as 30.3°C (86.54°F) were recorded where the Mackenzie River is flowing into the Arctic Ocean.

June 25, 2015 - High temperatures over North America, close to the Arctic Ocean

On July 1, 2015, temperatures are forecast to be as high as 111.4°F (or 44.1°C) near Chico, north of San Francisco. Temperatures are forecast to be high over most of North America and Eastern Siberia, threatening to further warm up waters of the Arctic Ocean.

Forecast for July 1, 2015 - High temperatures over North America, close to the Arctic Ocean

The image below shows that on June 27, 2015, temperatures of well over 40°C (104°F) were recorded in Europe and in Pakistan, where temperatures earlier this month had reached 49°C (120.2°F) in some places. The heat wave reportedly killed 1233 people in Karachi alone. This in addition to the 2500 people killed earlier in India by high temperatures.

June 27, 2015 - High temperatures over Russia, close to the Arctic Ocean
High temperatures at such locations are very worrying, for a number of reasons, including:
  • They are examples of heatwaves that can increasingly extend far to the north, all the way into the Arctic Ocean, speeding up warming of the Arctic Ocean seabed and threatening to unleash huge methane eruptions. 
  • They set the scene for wildfires that emit not only greenhouse gases such as carbon dioxide and methane, but also pollutants such as carbon monoxide (that depletes hydroxyl that could otherwise break down methane) and black carbon (that when settling on ice causes it to absorb more sunlight).
  • They cause warming of the water of rivers that end up in the Arctic Ocean, thus resulting in additional sea ice decline and warming of the Arctic Ocean seabed. 
June 24, 2015 - Smoke from wildfires in Alaska - from: wunderground.com
The image below shows increased sea surface temperature anomalies in the Arctic. Note the warming in the area of the Beaufort Sea where the Mackenzie River is flowing into the Arctic Ocean.


Very warm water is also flowing from the Pacific Ocean through the Bering Strait into the Arctic Ocean.  As the image below shows, the water that is flowing into the Arctic Ocean from the Pacific is much warmer than it used to be, as much as 6.1°C (10.98°F) warmer.

View the flow of the water on the animated version of above image at earth.nullschool.net
As said above, warm water flowing from rivers into the Arctic Ocean is a major contributor to these sea surface temperature anomalies. As also illustrated by the NOAA image below, rivers carrying warm water into the Bering Strait include the Kobuk River, the Naotak River and the Yukon River that flows all the way from British Columbia, Canada, through Alaska and ends in the Bering Strait. Sea surface temperatures near the coast of Alaska were as high as 19°C (66.2°F) from June 21-24, 2015.

Sea surface temperatures near the coast of Alaska as high as 19°C (66.2°F) from June 21-24, 2015
The Naval Research Laboratory animation below shows changes to Arctic sea ice thickness. Sea ice thickness (in m) down to zero where the Mackenzie River flows into the Arctic Ocean and in the Bering Strait where warm water from the Pacific is entering the Arctic Ocean.


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


Related

- Gulf Stream brings ever warmer water into Arctic Ocean
http://arctic-news.blogspot.com/2015/06/gulf-stream-brings-ever-warmer-water-into-arctic-ocean.html

- High Temperatures in the Arctic

- Heat Wave Forecast For Russia Early June 2015http://arctic-news.blogspot.com/2015/06/heat-wave-forecast-for-russia-early-june-2015.html

Sea surface temperature anomalies in the Arctic. Note the warming in the area of the Beaufort Sea where the Mackenzie...
Posted by Sam Carana on Thursday, June 25, 2015

Wednesday, April 16, 2014

Near-Term Human Extinction

Global Warming and Feedbacks

Is there a mechanism that could make humanity go extinct in the not-too-distant future, i.e. within a handful of decades?

Most people will be aware that emissions due to human activity are causing global warming, as illustrated by the arrow marked 1 in the image on the left. Global warming can cause changes to the land, to vegetation and to the weather. This can result in wildfires that can in turn cause emissions, thus closing the loop and forming a self-reinforcing cycle that progressively makes things worse.

Furthermore, less forests and soil carbon also constitute a decrease in carbon sinks, resulting in carbon that would otherwise have been absorbed by such sinks to instead remain in the atmosphere, thus causing more global warming, as illustrated by the additional downward arrow in the image on the right. In conclusion, there are a number of processes at work that can all reinforce the impact of global warming.

Emissions can also contribute more directly to land degradation, to changes in vegetation and to more extreme weather, as indicated by the additional arrow pointing upward in the image on the right. A recent study by Yuan Wang et al. found that aerosols formed by human activities from fast-growing Asian economies can cause more extreme weather, making storms along the Pacific storm track deeper, stronger, and more intense, while increasing precipitation and poleward heat transport.

Accelerated Warming in the Arctic

Similar developments appear to be taking place over the North Atlantic. Huge pollution clouds from North America are moving over the North Atlantic as the Earth spins. In addition, the Gulf Stream carries ever warmer water into the Arctic Ocean. As the image below shows, sea surface temperature anomalies at the highest end of the scale (8 degrees Celsius) are visible off the coast of North America, streching out all the way into the Arctic Ocean.


As said, feedbacks as are making the situation progressively worse. Feedback loops are causing warming in the Arctic to accelerate. Warming in the Arctic is accelerating with the demise of the snow and ice cover in the Arctic, and this is only feedback #1 out out many feedbacks that are hitting the Arctic, as described in an earlier post. As the temperature difference between the equator and the Arctic decreases, the Jet Stream is changing, making it easier for cold air to move out of the Arctic and for warm air from lower latitudes to move in (feedback #10).


Abrupt Climate Change leading to Extinction at Massive Scale

The danger is that, as temperatures over the Arctic Ocean warm up further and as the Gulf Stream carries ever warmer water into the Arctic Ocean, large quantitities of methane will erupt abruptly from the seafloor of the Arctic Ocean, adding a third kind of warming, runaway warming resulting in abrupt climate change, and leading to mass death, destruction and extiction of species including humans.

Persistence of such a progression makes it inevitable that the rest of Earth will follow the huge temperature rises in the Arctic. Massive wildfires will first ignite across higher latitudes, adding further greenhouse gas emissions and causing large deposits of soot on the remaining snow and ice on Earth, with a huge veil of methane eventually spreading around the globe. The poster below, from an earlier post, illustrates the danger.

[ click on image to enlarge - note that this is a 1.8 MB file that may take some time to fully load ]
Views by Contributors

How likely is it that the above mechanism will cause human extinction within the next few decades? What views do the various contributors to the Arctic-news blog have on this?

Guy McPherson has long argued that, given the strengths of the combined feedbacks and given the lack of political will to take action, near-term human extinction is virtually inevitable.

In the video below, Paul Beckwith responds to the question: Can climate change cause human extinction?


Further contributors are invited to have their views added to this post as well. While many contributors may largely share Paul Beckwith's comments, it's important to highlight that contributors each have their own views, and this extends to their preference for a specific plan of action.

Geo-engineering

One of the more controversial issues is the use of geo-engineering. Guy McPherson doesn't believe geo-engineering will be successful. In the video below, Paul Beckwith gives his (more positive) views on this.


I must admit that the lack of political will to act is rather depressing, especially given the huge challenges ahead. So, I can understand that this can make some of us pessimistic at times. Nonetheless, I am an optimist at heart and I am convinced that we can get it right by giving more support to a Climate Plan that is both comprehensive and effective, as discussed at ClimatePlan.blogspot.com

Tuesday, August 13, 2013

Arctic Death Spiral - Evolution to July 2013

Image by Andy Lee Robinson, from http://haveland.com/share/arctic-death-spiral.png
The video below is a visualization of the Arctic Death Spiral showing the evolution of the volume of sea-ice over time from 1979 to July 2013.

The rate of ice loss in the Arctic is staggering. Since 1979, the volume of Summer Arctic sea ice has declined by more than 80% and is accelerating faster than scientists believed it would, or even could melt.


Pitch of the notes are proportional to the average sea-ice volume for each month. Spectral filters are derived from the average sea-ice volume for each year. Produced using Perl and PovRay, Midi perl and Reason and Virtualdub on a cluster of Linux servers.


Above image is another way to visualize the data. It is a screenshot from the video below, by Andy Lee Robinson, illustrating the dramatic decline since 1979 until July 2013.

Andy Lee Robinson
The soundtrack "Arctic Requiem" also by Andy Lee Robinson, is available for free download: http://haveland.com/share/Arctic-Requiem.mp3

Sea Ice Volume is calculated using the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS, Zhang and Rothrock, 2003) developed at APL/PSC.

Source data is available from:
http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/


Monday, January 28, 2013

Further feedbacks of sea ice decline in the Arctic

Arctic sea ice currently acts as a shield, preventing methane from entering the atmosphere, concludes a study by researchers from two Chinese scientific institutes

The researchers observed more methane in the water under the sea ice than the methane in the air above the sea ice. They conclude that the sea ice collects and holds the methane in places close enough to the surface for the methane to be consumed through photochemical and biochemical oxidation. In other words, sufficient light can reach the spots where methane assembles underneath the ice for the methane to get consumed by biological processes.

Change of CH4 mixing ratio over time in the chamber on under-ice water. In CBS1–CBS3, CH4mixing ratios fluctuated in the first 1–2 h and then increased, suggesting significant emission of CH4. No increasing trend in CBS4 might due to the relatively short sampling time (only 2 h) during which CH4mixing ratio had not started increasing.
A study by the Alfred Wegener Institute led by Marcel Nicolaus has found that where melt water collects on the ice, far more sunlight and therefore energy is able to penetrate the ice than is the case for white ice without ponds. The consequence is that the ice is absorbing more solar heat, is melting faster, and more light is available for the ecosystems in and below the ice.

As the sea ice has decreased in volume over the years, there now is mainly thin, first-year ice, extensively covered with melt ponds in the summer months, where once metre-thick, multi-year ice used to be. Additionally, the melt ponds have a different color, causing further albedo change. “Their colour depends entirely on how thick the remaining ice below the melt pond is and the extent to which the dark ocean beneath can be seen through this ice. Melt ponds on thicker ice tend to be turquoise and those on thin ice dark blue to black”, explains Dr. Marcel Nicolaus, sea ice physicist and melt pond expert at the Alfred Wegener Institute.

Graphic depiction of the amount of sunlight above and underneath the Arctic sea ice. The growing coverage of the ice by darker meltponds increases the share of sunlight, which passes the sea ice. That means, the space underneath the ice becomes brighter and warmer. Furthermore less sunlight is refleced back into the atmosphere. Graphic: Marcel Nicolaus/Yves Nowak, Alfred Wegener Institute
Marcel Nicolaus explains: “The young thin ice with the many melt ponds does not just permit three times as much light to pass through than older ice. It also absorbs 50 per cent more solar radiation. This conversely means that this thin ice covered by melt ponds reflects considerably fewer sun rays than the thick ice. Its reflection rate is just 37 per cent. The young ice also absorbs more solar energy, which causes more melt. The ice melts from inside out to a certain extent,” says Marcel Nicolaus.

Marcel Nicolaus adds: “The greater the share of one-year ice in the sea ice cover, the more melt ponds will form and the larger they will be. This will also lead to a decreasing surface albedo (reflectivity) and transmission into the ice and ocean will increase. The sea ice will become more porous, more sunlight will penetrate the ice floes, and more heat will be absorbed by the ice. This is a development which will further accelerate the melting of the entire sea ice area.”

These studies contain an important warning. As the sea ice gets thinner, more sunlight and therefore energy is penetrating the ice and getting absorbed. Initially, this will increase the growth of bacteria that break down methane collecting underneath the sea ice. Eventually however, as sea ice retreats further, there will be less opportunities for methane to be held underneath the sea ice and broken down by bacteria. Instead, more methane will then enter the atmosphere unaffected.

These are further feedbacks of sea ice retreat, in addition to the many feedbacks described in the Diagram of Doom. Sea ice is declining at exponential pace. The big danger is that a huge rise of temperatures in the Arctic will destabilize huge amounts of methane currently held in the seabed. Comprehensive and effective action is needed now to avoid catastrophe.

References

- Sea ice in the Arctic Ocean: Role of shielding and consumption of methane - Xin He et al.
http://dx.doi.org/10.1016/j.atmosenv.2012.10.029

Melt ponds cause the Artic sea ice to melt more rapidly - Alfred Wegener Institute news release

- Changes in Arctic sea ice result in increasing light transmittance and absorption - Marcel Nicolaus et al. DOI: 10.1029/2012GL053738

Thursday, January 17, 2013

Accelerated Arctic Warming

The Arctic is warming much faster than the rest of the world, as illustrated by the NASA image below.

global temperature anomalies averaged from 2008 through 2012, NASA Goddard Institute for Space Studies
The interactive image below (no longer functioning, ed.) shows temperature anomalies for the different latitudional zones over time.

The Arctic shows the strongest warming over time, while accelerating in recent years. The best fit for this warming in the Arctic is a fourth order polynomial trendline, as added to the data on the image below.


This accelerated warming in the Arctic is threatening to destabilize the methane in the seabed and trigger runaway global warming within a decade. Effective action needs to be taken before it's too late!

Saturday, September 29, 2012

Accelerated Warming in the Arctic

Why is warming in the Arctic accelerating and where will this lead to?

Where does the extra heat go? 

Global warming is causing Earth to heat up. As shown on the image below, by Nuccitelli et al., most heat goes into the oceans.



Warming of water in the Arctic Ocean

White arrows mark ice drift directions. Red arrows mark
the transport path of warm Atlantic water entering the
Arctic where it submerges under the cold, ice-covered
surface layer.  Robert Spielhagen (IFM-GEOMAR, Kiel)
Global warming is heating up the oceans big time. As above image shows, the global ocean heat content has been rising for many years.

The Arctic is affected in particular by the Thermohaline Circulation.

Water flowing into the Arctic Ocean from the Atlantic Ocean is about 2°C warmer today than it has been for at least 2,000 years, according to a study published in Science. The current of warm water lies 50 metres below the surface, and can reach 6°C in summer — warm compared to Arctic surface waters, which can be -2°C.

At the same time, cold water and sea ice are driven out of the Arctic Ocean, along the edges of Greenland. The net result is a marked increase in the temperature of the water in the Arctic Ocean, especially the top layer of the water which causes the sea ice to melt.


The Arctic radiates comparatively less heat into space 

Cold layers of air close to the surface make it difficult for infrared radiation to go out to space, according to a study published in Science. These layers do warm up, but warming of these layers is directed downwards, thus amplifying warming in the Arctic.


Surface air temperatures in the Arctic are rising rapidly

Anomalies for surface air temperatures are higher in the Arctic than anywhere else on Earth. This is illustrated by the interactive images and text in the box at the bottom of this post.

The increase in temperature anomalies appears to be an exponential rise. This is caused not only by the above-described impacts of cold air close to the surface, but also by feedback effects as further described below.


Feedbacks further accelerate warming in the Arctic

Feedbacks are described in more detail in posts such as Diagram of Doom (image below) and Changes to Polar Vortex affect mile-deep ocean circulation patterns.


One such feedback is albedo change — retreat of Arctic sea ice results in less sunlight being reflected back into space, as further discussed in Albedo Change in the Arctic. Loss of Arctic sea ice is effectively doubling mankind's contribution to global warming. Increased absorption of the sun's rays is the equivalent of about 20 years of additional CO2 being added by man, Professor Peter Wadhams said in a recent BBC article.

One of the most threatening feedbacks is release of methane that are held in the currently frozen seabed. As the seabed warms up, it starts to release methane in what can be rather abrupt ways. Due to methane's high global warming potential, this can further accelerate local warming, triggering further methane releases, in a vicious circle that threatens to spiral into runaway global warming.

Tuesday, August 28, 2012

Diagram of Doom



Above diagram was part of a poster displayed at the 2011 AGU meeting in San Francisco by the Arctic Methane Emergency Group (AMEG). It was accompanied by the following text: In the Arctic, three problems are compounding one another: emissions causing global warming, sea ice loss causing accelerated warming, and methane releases further accelerating Arctic warming, with the danger of triggering runaway global warming.

The diagram pictures three kinds of warming and their main causes:
  1. Emissions by people causing global warming, with temperatures rising around the globe, including the Arctic.
  2. Soot, dust and volatile organic compounds settling down on snow and ice, causing albedo change. More heat is absorbed, rather than reflected as was previously the case. This causes accelerated warming in the Arctic.
  3. Accelerated warming in the Arctic threatening to weaken methane stores in the Arctic with the danger that methane releases will trigger runaway global warming.

The diagram also pictures two feedback effects that make things even worse:
  • Albedo feedback: Accelerated warming in the Arctic speeds up sea ice loss, further accelerating albedo change.
  • Methane feedback: Methane releases in the Arctic further add to the acceleration of warming in the Arctic, further contributing to weaken Arctic methane stores and increasing the danger that methane releases will trigger runaway global warming.

Albedo change in the Arctic comprises a number of elements, as depicted in the image below, from the 2004 report Impacts of a Warming Arctic - Arctic Climate Impact Assessmentby the International Arctic Science Committee.  


As described in various posts at this blog over time, there are further points that should be taken into account. Regarding sea ice loss, it's clear that where sea ice retreats, more open water appears, with the result that less sunlight is reflected back into space. Accelerated warming will also affect the integrity of the remaining sea ice, as well as of the snow and ice cover on land, including glaciers. This further adds to the albedo effect, causing less sunlight to be reflected back into space. Similarly, further feedbacks could be added or described in more detail.

Accordingly, ten feedbacks can be identified, and described as follows:
  1. Albedo feedback: Accelerated warming in the Arctic speeds up the decline of ice and snow cover, further accelerating albedo change. 
  2. Methane feedback: Methane releases in the Arctic further add to the acceleration of warming in the Arctic, further contributing to weaken Arctic methane stores and increasing the danger that methane releases will trigger runaway global warming. 
  3. Currents feedback: Sea ice loss can cause vertical sea currents to weaken, reducing the cooling effect they had on the seabed. This can thus further cause sediments to warm up that can contain huge amounts of methane in the form of free gas and hydrates. 
  4. Storms feedback: Increased frequency and intensity of storms can cause substantially more vertical mixing of the sea water column, causing more warming of the seabed, thus further contributing to the warming of sediments, as above. 
  5. Storms feedback: Accelerated warming in the Arctic can result in more storms, causing mixing of cold Arctic air with warmer air from outside the Arctic. The net result is a warmer Arctic. 
  6. Storms feedback: More open waters can result in more storms that can push the ice across the Arctic Ocean, and possibly all the way out of the Arctic Ocean. 
  7. Storms feedback: Storms also cause more waves that break up the sea ice. Smaller pieces of ice melt quicker than large pieces. A large flat and solid layer of ice is also less susceptible to wind than many lighter and smaller pieces of ice that will stand out above the water and capture the wind like the sails of yachts. 
  8. Storms feedback: Storms cause waters to become more wavy. Calm waters can reflect much sunlight back into space, acting as a mirror, especially when the sun shines under a low angle. Wavy waters, on the other hand, absorb more sunlight. 
  9. Fires feedback: More extreme weather comes with heatwaves and storms. Thus, this is in part another storms feedback. The combination of storms and fires can be deadly. Heatwaves can spark fires that, when fueled up by storms, turn into firestorms affecting huge areas and causing huge amounts of emissions. Storms can whip up particles that when deposited on ice, snow or the bare soil, can cause more sunlight to be absorbed. 
  10. Open doors feedback: Accelerated warming in the Arctic causes the polar vortex and jet stream to weaken, causing more extreme weather and making it easier for warm air to enter the Arctic.

These ten feedback are depicted in the diagram below.