Showing posts with label albedo. Show all posts
Showing posts with label albedo. Show all posts

Saturday, October 10, 2015

Arctic Sea Ice 2015 - update 11

Arctic sea ice extent has been growing rapidly recently. The image below shows extent up to October 9, 2015 (marked by red dot).


Below is a comparison of sea ice thickness as on October 6, for the years (from left to right) 2012, 2013, 2014 and 2015. The comparison shows that decline has been strongest where sea ice used to be the thickest, i.e. over 3 meters thick.


One of the reasons why the thickest Arctic sea ice has declined so dramatically over the years is the rising ocean heat that is melting the sea ice from underneath. The image below illustrates the situation on October 5, 2015, when sea surface temperature anomalies were as high as 6.4°C, 7.4°C and 7.3°C (11.5°F 13.2°F and 13.1°F) off the North American coast, and as high as 9.4°C (16.8°F) near Svalbard.


Water temperatures are very high in the Arctic, as further illustrated by the image below showing Arctic sea surface temperature anomalies as at October 9, 2015.



Rising ocean heat is further illustrated by the graph below, showing August sea surface temperature anomalies on the Northern Hemisphere over the years.
The situation is very dangerous, due to feedbacks and their interaction. The thicker sea ice used to act as a buffer, consuming ocean heat in the melting process. Without thicker sea ice, ocean heat threatens to melt the sea ice from below right up to the surface, causing the entire sea ice to collapse. As the sea ice declines, more open water will give rise to stronger winds and waves.

Furthermore, sunlight that was previously reflected back into space will instead be absorbed by the water, causing rapid rise of the temperature of the water. In places such as the East Siberian Arctic Shelf, the water is on a average only 50 m deep, so warmer water is able to reach the seafloor more easily there. As ocean heat keeps rising, there's a growing risk that heat will reach the Arctic Ocean seafloor and destabilize methane hydrates in sediments at the Arctic Ocean seafloor.

The image below shows a non-linear trend that is contained in the temperature data that NASA has gathered over the years, as described in an earlier post. A polynomial trendline points at global temperature anomalies of over 4°C by 2060. Even worse, a polynomial trend for the Arctic shows temperature anomalies of over 4°C by 2020, 6°C by 2030 and 15°C by 2050, threatening to cause major feedbacks to kick in, including albedo changes and methane releases that will trigger runaway global warming that looks set to eventually catch up with accelerated warming in the Arctic and result in global temperature anomalies of 16°C by 2052.

[ click on image to enlarge ]
The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.

Comparison of sea ice thickness on October 6, for the years (from left to right) 2012, 2013, 2014 and 2015, shows that...

Posted by Sam Carana on Saturday, October 10, 2015

Thursday, September 10, 2015

3.27°C warmer by 2030?

Will it be 3.27°C warmer by the year 2030?
In December 2015, world delegates will descend on Paris to ensure that global warming will not cross the guardrail of 2°C above pre-industrial levels.

[ click on images to enlarge them ]
In a way, we have already crossed this guardrail. NOAA data show that the year-to-date land surface temperature was 1.47°C above the 20th century average on the Northern Hemisphere in 2015, as illustrated by the image on the right.

Granted, there was less warming on the Southern Hemisphere, so the globally-averaged land surface temperature was a little bit lower, i.e. 1.34°C above the 20th century average. For reference, the image below on the right gives an overview of mean 1901-2000 temperatures. Anyway, the difference between hemispheres is small and not very relevant since most people live on the Northern Hemisphere.

[ click on image to enlarge ]
More importantly, this 1.47°C rise is a rise compared to the 20th century average. The 20th century average was some 0.60°C higher than temperatures were at the start of the NOAA record in 1880. In other words, temperatures for most people on Earth are already 2.07°C higher than they were in 1880.

Furthermore, between 1750 and 1880 the global average temperature had already increased by some 0.20°C.

Sure, 2015 is an El Niño year, but this El Niño is still strengthening, so 2016 could well be even warmer. Moreover, recent temperatures are in line with expectations of a polynomial trendline that is based on these NOAA data and that points at yet another degree Celsius rise by 2030, on top of the current level, as illustrated by the top image. Altogether, this would make it 3.27°C warmer than in 1750 for most people on Earth by the year 2030.

So, instead of acting as if dangerous global warming could possibly eventuate beyond the year 2100, delegates in Paris should commit to lowering temperatures, starting now.

To lower temperatures, cutting emissions alone will not be enough.

Stopping all emissions by people would make that the aerosols that are currently sent up in the air by burning fuel and that are currently masking the full impact of global warming, will fall out of the air in a matter of weeks. Until now, about half of the global temperature rise is suppressed by such aerosols. Stopping aerosols release overnight could make temperatures rise abruptly by 1.20°C in a matter of weeks.

Furthermore, carbon dioxide that is emitted now will take ten years to reach its peak impact, so we're still awaiting the full wrath of carbon dioxide emitted over the past decade.

A recent study calculates that global mean surface temperature may increase by 0.50°C after carbon emissions are stopped, and they will decrease only minimally from that level for the next 10,000 years.

Removing carbon dioxide from the atmosphere would not work fast enough to avoid further warming and acidification of the oceans. In fact, temperatures look set to rise even faster as feedbacks start to kick in more fully, such as albedo changes due to decline of the snow and ice cover in the Arctic and methane releases from the Arctic Ocean seafloor. Furthermore, water vapor will increase by 7% for every 1°C warming. Water vapor is one of the strongest greenhouse gases, so increasing water vapor will further contribute to a non-linear temperature rise.

In conclusion, the world needs to commit to comprehensive and effective action that includes both emission cuts and removal of greenhouse gases from the atmosphere and oceans, as well as further action to deal with the dire situation in the Arctic, as discussed at the Arctic-news Blog.




In December 2015, world delegates will descend on Paris to ensure that global warming will not cross the guardrail of 2°...
Posted by Sam Carana on Thursday, September 10, 2015

Friday, July 10, 2015

Arctic Sea Ice Collapse Threatens

The image below compares the Arctic sea ice thickness on July 14, 2012 (left panel) and on July 14, 2015 (right panel), using Naval Research Laboratory images.


The Naval Research Laboratory's 30-day animation below shows how this situation developed, ending with a forecast for July 17, 2015, run on July 9, 2015.


The dramatic decline of the sea ice, especially north of North America, is the result of a combination of factors, including:

  • very high levels of greenhouse gases over the Arctic Ocean
  • very high levels of ocean heat 
  • heatwaves over North America and Siberia extending high air temperatures over the Arctic Ocean
  • wildfires triggered by these heatwaves resulting in darkening compounds settling on snow and ice
  • very warm river water running into the Arctic Ocean, as illustrated by the image below.  


With still two months of melting to go before the sea ice can be expected to reach its minimum for 2015, the threat of sea ice collapse is ominous. The Arctic-News Blog has been warning for years about the growing chance of a collapse of the sea ice, in which case huge amounts of sunlight that previously were reflected back into space, as well as heat that previously went into melting the ice, will then instead have to be absorbed by the water, resulting in a dramatic rise of sea surface temperatures.

The image below shows the already very high sea surface temperature anomalies as at July 10, 2015.


More open water will then come with an increased chance of storms that can cause high sea surface temperatures to be mixed down all the way to seafloor of the Arctic Ocean, which in many cases is less than 50 m (164 ft) deep.

Meanwhile, ocean heat is accumulating off the coast of North America, as illustrated by the image below showing sea surface temperature as high as 31.8°C (89.24°F) on July 8-9, 2015.


Massive amounts of ocean heat will be carried by the Gulf Stream into the Arctic Ocean over the next few months. The combined result of high sea surface temperatures being mixed down to the seafloor and the ocean heat entering the Arctic Ocean from the Atlantic and Pacific Oceans can be expected to result in dramatic methane eruptions from the Arctic Ocean seafloor by October 2015.

Currently, methane levels are high, especially north of Greenland, as illustrated by the image below showing that on July 10, 2015 (am), levels as high as 2416 parts per billion were recorded at 6,041 m (19,820 ft) altitude, while mean methane levels also reached 1831 parts per billion at this altitude.


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





ARCTIC SEA ICE COLLAPSE THREATENSThis image compares the Arctic sea ice thickness on July 14, 2012 (left panel) and on...
Posted by Sam Carana on Friday, July 10, 2015

Friday, June 5, 2015

High Temperatures in the Arctic


The images below illustrate extremely high temperatures forecast to hit Russia on June 6, 2015, as also discussed in the previous post.


A temperature of 29.4°C (84.92°F) is forecast for the location at the green circle for June 6, 2015. The location is close to the Arctic Ocean and to rivers ending in the Arctic Ocean, as also shown on the image below.


The location, at a latitude of 66.48°N, is approximately on the Arctic Circle, which runs 66°33′45.8″ north of the Equator. North of the Arctic Circle, the sun is above the horizon for 24 continuous hours at least once a year.


The many hours of sunshine make that, during the months June and July, insolation in the Arctic is higher than anywhere else on Earth, as shown on above image, by Pidwirny (2006).
Insolation, with contour labels (green) in units of W m−2

The size of the June snow and ice cover is so vitally important as insolation in the Arctic is at its highest at the June Solstice.

The Wikipedia image on the right calculates the theoretical daily-average insolation at the top of the atmosphere, where θ is the polar angle of the Earth's orbit, and θ = 0 at the vernal equinox, and θ = 90° at the summer solstice; φ is the latitude of the Earth.

The calculation assumed conditions appropriate for 2000 A.D.: a solar constant of S0 = 1367 W m−2, obliquity of ε = 23.4398°, longitude of perihelion of ϖ = 282.895°, eccentricity e = 0.016704.

Snow and ice cover on land can take up a large area, even larger than sea ice. In May 2015, the area of snow extent on the Northern Hemisphere was 17 million square km, while sea ice extent in May 2015 was below 13.5 million square km. 

Northern Hemisphere snow, May 2015. Credit: Rutgers University Global Snow Lab
The chart below shows the decline of snow cover on land on the Northern Hemisphere in Spring over the years. 

Credit: Rutgers University Global Snow Lab
High temperatures over the Arctic Ocean are heating up the snow cover on land and the sea ice from above. High temperatures also set the scene for wildfires that can emit huge amounts of pollutants, including dust and black carbon that, when settling on the sea ice, can cause its reflectivity to fall. Rivers furthermore feed warm water into the Arctic Ocean, further heating up the sea ice from below. 

The image below shows Arctic sea ice extent at June 3, 2015, when Arctic sea ice extent was merely 11.624 million square kilometers, a record low for the time of the year since satellite started measurements in 1979. 



Sea ice melting occurs due to heat from above, i.e. absorbed sunlight. Once the sea ice is gone, energy from sunlight that previously went into melting and transforming ice into water, will instead go into warming up the Arctic Ocean and the sediments under the seafloor.

In addition, sea ice is also melting due to heat from below. Much of this heat is carried by the Gulf Stream and by rivers into the Arctic Ocean. Once the sea ice is gone, all this heat will go into warming up the Arctic Ocean and the sediments under the seafloor.

The sea ice acts as a heat buffer by absorbing energy in the process of melting. In other words, as long as there is sea ice, it will absorb heat and this will prevent this heat from raising the temperature of the water in the Arctic. Once the sea ice is gone, this latent heat must go elsewhere.

As the sea ice heats up, 2.06 J/g of heat goes into every degree Celsius that the temperature of the ice rises. While the ice is melting, all energy (at 334J/g) goes into changing ice into water and the temperature remains at 0°C (273.15K, 32°F).

Once all ice has turned into water, all subsequent heat goes into heating up the water, at 4.18 J/g for every degree Celsius that the temperature of water rises.

The amount of energy absorbed by melting ice is as much as it takes to heat an equivalent mass of water from zero to 80°C. The energy required to melt a volume of ice can raise the temperature of the same volume of rock by 150º C.
Decline of Arctic sea ice means that a lot more heat will be absorbed by the Arctic Ocean.



Thick sea ice covered with snow can reflect as much as 90% of the incoming solar radiation. After the snow begins to melt, and because shallow melt ponds have an albedo (or reflectivity) of approximately 0.2 to 0.4, the surface albedo drops to about 0.75. As melt ponds grow and deepen, the surface albedo can drop to 0.15, while the ocean reflects only 6% of the incoming solar radiation and absorbs the rest.

As Professor Peter Wadhams, University of Cambridge, once calculated, a collapse of the sea ice would go hand on hand with dramatic loss of snow and ice cover on land in the Arctic. The albedo change resulting from the snowline retreat on land is similarly large as the retreat of sea ice, so the combined impact could be well over 2 W/sq m. To put this in context, 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, estimated by the IPCC to be 1.6 W/sq m in 2007 and 2.29 W/sq m in 2013.

Professor Peter Wadhams on albedo changes in the Arctic

Update June 8, 2015: The website at earth.nullschool.net shows that over the past few days temperatures over 30°C (86°F) were reached at several locations over rivers ending up in the Arctic Ocean.

The animation below, by ClimateReanalyzer, shows the heat wave and the storm that hit the Arctic recently.

This animation shows the current GFS model 8-day forecast for the Arctic for six meteorological parameters (precip/cloudcover; wind, pressure, precipitable water, temperature, temperature anomaly). The forecast begins with an impressive storm twirling around the North Pole with 10-meter winds peaking around 55 km/h (~35 mi/h), which fades as the low pressure breaks down. The storm is coupled to an early season heat wave that hit Siberia this week with the development of a high amplitude ridge in the jet stream.In mid August 2012, a comparable storm churned up the sea ice and contributed to the record minimum ice extent that emerged in September. Arctic sea ice is more resilient to wind in early June when it is still relatively thick and compacted than it is in mid August towards the end of the melt season. This current storm is therefore unlikely to have the same impact as the Aug 2012 storm. But the event is worth mentioning nonetheless.

Posted by Climate Reanalyzer on Sunday, June 7, 2015

Arctic sea ice extent at June 3, 2015, was merely 11.624 million square kilometers, a record low for the time of the...

Posted by Sam Carana on Friday, June 5, 2015

Sunday, February 22, 2015

Multiple Benefits Of Ocean Tunnels

By Sam Carana and Patrick McNulty

Comprehensive climate action will do more than just cutting emissions, it will also take further action, as pictured in the image below.

Comprehensive and effective action is discussed at the Climate Plan blog
Taking a broad perspective makes it easier for proposed projects to be assessed on their benefits in a multitude of areas.

Ocean tunnels can capture vast amounts of energy from ocean currents, such as the Gulf Stream and the Kuroshio Current. These locations are close to areas with high energy demand, such as the North American East Coast and the coast of East Asia, which can reduce the need for long distance transmission lines.

Ocean tunnels provide clean energy continuously, i.e. 24 hours a day, all year long. This makes that they can satisfy demand for electricity both at peak and off-peak usage times.

  • Their ability to supply large amounts of electricity at times of peak demand will benefit the necessary transition from polluting to clean ways of generating electricity.
  • Their ability to also supply large amounts of electricity at off-peak usage times will help to reduce the price of electricity at such times, thus opening up opportunities for a number of activities that can take place at off-peak hours and that require large amounts of energy.

    Such activities include large-scale grinding of olivine rock and transport of the resulting olivine sand, and large-scale production of hydrogen through electrolysis to power transport (box right). Electrolysis can also create oxygen-enriched water that can improve the quality of waters that are oxygen-depleted.  
Hydrogen to power Shipping

Ocean tunnels can make electricity cheap at off-peak times. This will reduce the cost of recharging batteries of electric vehicles at night.

It will also reduce the cost of producing hydrogen at off-peak hours. To power ships crossing the oceans, hydrogen looks more cost-effective, as such ships cannot return to base for a nighly battery recharge. Such ships have plenty of cargo space to carry hydrogen, even when the hydrogen is not highly compressed. Some of the world's largest ports are close to strong ocean currents.




Ocean tunnels can generate electricity in two ways, i.e. by capturing the kinetic energy contained in the flow of ocean currents, and by means of Ocean Thermal Energy Conversion (OTEC) using temperature differences between cooler deeper parts of the ocean and warmer surface waters to run a heat engine to produce energy. 

Besides generating energy, ocean tunnels can assist with further activities, which will increase the value of ocean tunnels in the fight against climate change. Such activities include the following:
  • By reaching deeper parts of the ocean, OTEC can pull up sunken nutrients and put them out at surface level to fertilize the waters there, while the colder water that is the output of OTEC will float down, taking along newly-grown plankton to the ocean depths before it can revert to CO2, as described in the earlier post Using the Oceans to Remove CO2 from the Atmosphere.
  • Ocean tunnels can be used to distribute olivine sand in the water. The force of the currents and the turbines will help the process of transforming olivine into bicarbonate. This can reduce carbon dioxide levels in the water by sequestering carbon, while also reducing ocean acidification. Olivine sand contains silicate and small amounts of iron, allowing diatoms to grow that will capture additional carbon dioxide, while also raising levels of free oxygen in the water. The latter will stimulate growth of microbes that break down methane in the water before it reaches the atmosphere. Further nutrients can be added, as also discussed in this earlier post
  • Ocean tunnels can also assist with albedo changes. Ocean tunnels can act as the infrastructure to create water microbubbles along their track. Increasing water albedo in this way can reduce solar energy absorption by as much as 100 W m − 2, potentially reducing equilibrium temperatures of standing water bodies by several Kelvins, as Russel Seitz wrote back in 2010. There may also be potential for ocean tunnels to be used to spray water vapor into the air with the aim of brightening clouds over areas where it counts most.
  • The turbines in tunnels will also reduce the flow of ocean currents somewhat, thus reducing the flow of warm water into the Arctic. Furthermore, tunnels can be shaped in ways to guide the flow of warm water away from the Arctic Ocean down a southwards course along the Canary Current along the coast of West Africa. thus diverting warm water that would otherwise end up in the Arctic Ocean. This could also reduce the chance of hurricanes hitting the east coast of North America, as Sandy did in 2012.  
The Gulf Stream, carrying warm water all the way into the Arctic Ocean



Monday, February 16, 2015

Climate Changed

Our climate has changed, as illustrated by the image below (Forecast for Feb. 23, 2015, 1200 UTC, run on Feb. 16, 2015).


The left map shows temperatures of 40 degrees below zero moving down into North America from the Arctic, while temperatures in much of Alaska are above freezing point. The right map shows temperature anomalies over large parts of North America at both the top end (red) and the bottom end (purple) of the scale. Temperature anomaly forecasts for the week from Feb 19 to 26, 2015, feature in the video below.



Below is an update showing operational temperature anomalies recorded on February 23, 2015.


As parts of North America experienced record cold, part of Alaska was more than 20°C (36°F)
warmer than it used to be (compared to 1985-1996). And despite the cold weather in parts of Canada and Greenland, the Arctic as a whole is forecast to reach, on February 26, temperature anomalies as much as 3.32°C (6°F) above what temperatures used to be from 1979 to 2000 (Climate Reanalyzer forecast data).

What has caused our climate to change in this way? The image below shows that the jet stream, which once used to move over North America horizontally, has become more wavy, pushing warm air north on the left, while drawing cold air from the Arctic south on the right.


Importantly, while the jet stream is becoming more wavy or elongated vertically, the speed at which it crosses the oceans can increase dramatically. This can be the case where low temperatures over land and high sea surface temperatures combine to create huge temperature differences that drive up the jet stream's speed over oceans.

This is illustrated by the image below showing the Jet Stream reaching speeds as high as 410 km/h (or 255 mph) at the green circle near Greenland on January 9, 2015 (left), and speeds as high as 403 km/h (or 250 mph) at the green circle near Greenland on February 20, 2015 (right).


The reference map on the right shows the location of the continents for the same orthgraphic coordinates as the maps above and below.

Similarly, the Polar Vortex can reach high speeds, driving cold air downward over North America and driving warm air upward over Greenland and the North Atlantic.

The image below shows the Polar Vortex reaching speeds as high as 346 km/h (or 215 mph) at the green circle near Svalbard on January 18, 2015 (left), and speeds as high as 316 km/h (or 196.4 mph) at the green circle over the Arctic Ocean on February 9, 2015 (right).


Almost one year ago, the Polar Vortex also reached speeds as high as 410 km/h (or 255 mph), as discussed in an earlier post. Changes to the polar vortex and the jet stream are caused by emissions, and the situation looks set to deteriorate even further.


Above image illustrates that, on February 16, 2015, waves higher than 10 m (32.81 ft) were recorded off the east coast of North America and south of Iceland, while waves as high as 8.15 m (26.74 ft) were recorded in between Norway and Svalbard.

As above images also illustrate, changed wind patterns are carrying warm air high up into the Arctic.

The air that is moving north is much warmer than it used to be, as sea surface temperatures off the east coast of North America are much higher than they used to be (image left and as discussed in an earlier post).

Strong winds increase the volume of warm water that the Gulf Stream carries into the Arctic Ocean. They can also cause rain storms that can devastate Arctic ice and glaciers

Arctic sea ice currently has about the lowest extent for the time of the year since satellite measurements started in 1979.

The image below shows that, on February 17, 2015, Arctic sea ice had reached an extent of merely 14.406 million square kilometers.

click on image to enlarge
The Arctic sea-ice Monitor image below shows an extent of 13,774,725 km2 for February 18, 2015, with the red line illustrating the recent fall in extent even more dramatically.

Below is a 30-day animation showing sea ice thickness (in m) up to February 22, 2015 (and forecast up to March 2), from the U.S. Naval Research Laboratory.


As the Arctic's snow and ice cover decline, more sunlight gets absorbed that previously was reflected back into space. All this adds up to a very dangerous situation, since huge amounts of methane are contained in sediments under the seafloor of the Arctic Ocean, and they can get destabilized as the water warms up.

In conclusion, feedbacks make that the Arctic is warming more rapidly than the rest of the globe and they threaten to trigger huge methane eruptions from the seafloor of the Arctic Ocean.

Methane concentrations over the Arctic Ocean are very high at the moment. The image below shows the very high peak methane levels that have recently been recorded, against a background image showing high methane levels over the East Siberian Arctic Shelf on February 20, 2015.


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



Friday, October 3, 2014

Where we are - A climate system summary

by Paul Beckwith



Air


The presence of GHGs (greenhouse gases) in the atmosphere is vital to sustain life on our planet. These GHGs trap heat and keep the global average surface temperature of the planet at about 15°C, versus a chilly -18°C, which would be our temperature without the GHGs.

We have changed the chemistry of the atmosphere, specifically of the concentrations of the GHGs. Concentrations of carbon dioxide have increased about 40% since the start of the industrial revolution (from a tight range between 180 to 280 ppm over at least the last million years) to 400 ppm. Concentrations of methane have increased by more than 2.5x since the start of the industrial revolution (from a tight range of 350 to 700 ppb) to over 1800 ppb. The additional heat trapped has warmed our planet by over 0.8°C over the last century, with most of that rise (0.6°C) occurring in the last 3 or 4 decades.

Oceans

Over 90% of the heat trapped on the surface of the planet is increasing the temperature of the ocean water. The increased levels of carbon dioxide in the atmosphere acidify the rainfall, and have increased the acidity of the oceans by about 40% in the last 3 to 4 decades (pH of the open ocean has dropped from 8.2 down to 8.05 on the logarithmic scale). An increased drop to a pH of 7.8 will prevent calcium based shells from forming, and threaten the entire food chain of the ocean. Changes in ocean currents, and vertical temperature profiles are leading to more stratification and less overturning which is required to transport nutrients to the surface for phytoplankton to thrive.

Global sea levels are presently rising at a rate of 3.4 mm per year, compared to a rate of about 2 mm per year a few decades ago. Melt rates on Greenland have doubled in the last 4 to 5 years, and melt rates on the Antarctica Peninsula have increased even faster. Based on the last several decades, melt rates have had a doubling period of around 7 years or so. If this trend continues, we can expect a sea level rise approaching 7 meters by 2070.

From: More than 2.5 m sea level rise by 2040
Land

Higher global average temperatures have increased the amount of water vapor in the atmosphere by about 4% over the last several decades, and around 6% since the start of the industrial revolution. Changes in heat distribution with latitude from uneven heating with latitude has slowed the jet streams and caused them to become wavier and fractured, and has changed the statistics of weather. We now have higher frequencies, intensities, and longer duration extreme weather events and also a change in location of where these events occur.

Feedback loops

The sensitivity of the climate system to increased levels of GHG appears to be much higher than previously expected due to many powerful reinforcing feedbacks.

From: Arctic Warming due to Snow and Ice Demise

Arctic temperature amplification from exponentially declining sea ice and spring snow cover are the strongest feedbacks in our climate system today. The average albedo (reflectivity) of the Arctic region has decreased from 52% to a present day value of 48% over 3 or 4 decades. The increased absorption of energy in the Arctic has increased the temperature at high latitudes at rates up to 6 to 8x the global average temperature change. The reduced temperature difference between the Arctic and equator has reduced the west to east speed of the jet streams causing them to slow and become wavier and more fractured, and directly causing a large change in the statistics of our global weather.

Methane gas emissions have been rapidly rising in the Arctic region from the terrestrial permafrost and the continental shelf marine sediments, most notably on the ESAS (Eastern Siberia Arctic Shelf). The extremely potent ability of methane to warm the planet (global warming potential GWP is >150, 86, and 34 times for methane relative to carbon dioxide on a few year, several decade, and century timescale, respectively) makes increased emissions an extremely dangerous risk to our well-being on the planet.

My overall assessment

Our climate system is presently undergoing preliminary stages of abrupt climate change. If allowed to continue, the planet climate system is quite capable of undergoing an average global temperature increase of 5°C to 6°C over a decade or two. Precedence for changes at such a large rate can be found at numerous times in the paleo-records. From my chair, I conclude that it is vital that we slash greenhouse gas emissions and undergo a crash program of climate engineering to cool the Arctic region and keep the methane in place in the permafrost and ocean sediments.


Paul Beckwith
Paul Beckwith is part-time professor with the laboratory for paleoclimatology and climatology, department of geography, University of Ottawa. Paul teaches climatology/meteorology and does PhD research on 'Abrupt climate change in the past and present'. Paul holds an M.Sc. in laser physics and a B.Eng. in engineering physics and reached the rank of chess master in a previous life. Click here to view Paul's earlier posts at the Arctic-news blog.


Related

- What's wrong with the weather?
http://arctic-news.blogspot.com/2014/07/whats-wrong-with-the-weather.html

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



Friday, August 15, 2014

Heatwave to hit Greenland

A heatwave with temperature anomalies exceeding 36°F (20°C) is expected to hit Greenland between August 16 and 22, 2014, as illustrated by the image on the left and the animation on the right. 

Such heatwaves can be expected to hit the Arctic more frequently and with greater intensity, as temperatures in the Arctic are rising faster than elsewhere on Earth.

Such heatwaves can result in massive melting on Greenland, as persistent heat changes the texture of the snow and ice cover, in turn reducing its reflectivity. This makes that less sunlight is reflected back into space and is instead absorbed. 

The image below illustrates what a difference the presence of sea ice can make.
from: Arctic Warming due to Snow and Ice Demise
As the NSIDC/NOAA graphs below shows, melting on Greenland has been relatively modest this year when compared to the situation in 2012. By July 12, 2012, 97% of the ice sheet surface had thawed, according to this NASA analysis and this NOAA Arctic Report Card.


Melting on Greenland directly affects sea level rise, and melting on Greenland is accelerating due to a number of factors.

Projections of melting on Greenland have long been based on a warming atmosphere only, ignoring the warmer waters that lubricate glaciers and that warm Greenland's bedrock canyons that sit well below sea level.

Furthermore, there are growing quantities of black carbon deposits as a result of burning of fossil fuel and biomass. High temperatures have recently caused ferocious wildfires in Canada that have in turn caused a lot of black carbon to go up high into the atmosphere.

And of course, the atmosphere over the Arctic is warming up much faster than most models had projected. This in turn causes triggers further feebacks, including more extreme weather events such as heatwaves and rain storms that can be expected to hit Greenland with ever more frequency and ferocity. Further feedbacks include methane eruptions from the heights of Greenland, as discussed at the Arctic Feedbacks Page.

When also taking into account the accelerating impact of such factors on melting in Greenland, sea levels could rise much faster than anticipated, as illustrated by the image below.

from: more than 2.5m sea level rise by 2040? 

Note that sea level rise is only one of the many dangers of global warming, as discussed in the 2007 post Ten Dangers of Global Warming.

The image on the right shows a temperature forecast for August 16, 2014, with parts of Greenland changing in color from blue into green, i.e. above the melting point for snow and ice.

Such high temperatures are now hitting locations close to the North Pole ever more frequently, due to the many feedbacks that are accelerating warming in the Arctic, as discussed at this Feedbacks page.

One of the most dangerous feedbacks is a sudden eruption of huge quantities of methane from the seafloor of the Arctic Ocean, as discussed in a recent post.

The impact of such feedbacks can be accumulative and interactive, resulting in self-reinforcing feedbacks loops that can escalate into runaway warming.

Below is another forecast by ClimateReanalyzer for August 16, 2014, showing the remarkable ‘greening’ of Greenland, as well as the very high temperatures reaching the higher latitudes of North America.


Also see the very high sea surface temperatures around Greenland on the image below, created with ClimateReanalyzer.

Sea surface temperature anomalies on August 15, 2014. 
In conclusion, the situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan blog