Sunday, July 10, 2016

Extreme Weather Events


Sea ice close to the North Pole looks slushy and fractured into small pieces. The image below shows the situation on July 8, 2016.

Sea ice north of the geographic North Pole. For more on the (geo)magnetic North Pole, see this page
For reference, the bars at the bottom right show distances of 20 km and 20 miles. By comparison, sea ice in the same area did develop large cracks in 2012, but even in September 13, 2012, it was not broken up into small pieces, as shown by this image at a recent post.


As shown by above image, by Jim Pettit, Arctic sea ice volume has been in decline for decades. While this may look like a steady decline, chances are that the sea ice will abruptly collapse over the next two months, for the reasons described below.

The animation below, from the Naval Research Laboratory, shows Arctic sea ice thickness for 30 days up through July 8, 2016, including a forecast of 7 days.

Below is a new Naval Research Laboratory image, dated July 4, 2016
and contributed by Albert Kallio with the following description.


NORTH POLE SEA ICE DISAPPEARING VERY RAPIDLY 4.7.2016

Albert Kallio: The upgraded US Navy sea ice thickness system revealed extreme rates of sea ice pulverization and melting on 4.7.2016 which justifies a continued close attention to the developments on the Arctic Ocean. Due to virtually continuous storm centering the North Pole for weeks now, warm water upswells and sea water mixing drives base melting of icefloes besides wave actions that both wash and pulverize broken sea ice. The more pulverized sea ice becomes, the greater its 3-dimensional surface area that sits in water becomes, this easing transfer of heat from ocean to sea ice. In addition, honeycombing of ice also flushes ice with water in a stormy weather. The final factor being that most of sea ice is very recent (seasonal) ice that contain residues of salts, when saline brine is expelled this creates boreholes into ice making it "rotten ice" easily.
https://www7320.nrlssc.navy.mil/GLBhycomcice-12/navo/arcticictn_nowcast_anim30d.gif
Sea ice decline reflects the extra energy added to the Arctic, as global warming and feedbacks are hitting the Arctic particularly strongly. Three of these feedbacks are depicted in the image on the right.

As the sea ice melts, sea surface temperatures will remain at around zero degree Celsius (32°F) for as long as there is ice in the water, since the extra energy will first go into melting the ice. Only after the ice has melted will the extra energy start raising the temperature of the water.

Sea ice thus acts as a buffer that absorbs heat, preventing sea surface temperature from rising. As
sea ice is busy melting, each gram of ice takes 334 Joule of heat to change into water, while the temperature remains steady at 0°C ( 32°F).

Once all ice has turned into water, all further heat goes into raising the temperature of the water. To raise the temperature of each gram of water by one degree Celsius then takes only 4.18 Joule of heat.

In other words, melting of the ice absorbs 8 times as much heat as it takes to warm up the same mass of water from zero to 10°C. As sea ice disappears, extra energy instead goes into raising the temperature of the water, as depicted in the image on the right, and as further described at the feedbacks page as feedback #14.

Sea ice can reflect as much as 90% of the sunlight back into space. Once the ice has melted away, the water of the ocean reflects only 6% of the incoming solar radiation and absorbs the rest. Albedo change is depicted in above image as feedback #1. As Professor Peter Wadhams once calculated, warming due to Arctic snow and ice loss could more than double the net warming now caused by all emissions by all people of the world.

Professor Peter Wadhams on albedo changes in the Arctic, image from Edge of Extinction
Once the sea ice has disappeared, a lot more energy will get absorbed by the Arctic Ocean, i.e. energy that was previously reflected back into space and energy that previously went into changing ice into water.

Furthermore, as the sea ice disappears, chances increase that storms will develop that come with rain and winds that can batter and push the remaining sea ice out of the Arctic Ocean, while storms can also increase the amount of water vapor in the atmosphere and the occurrence of cirrus clouds that can trap heat.

Methane is a further feedback, depicted as feedback #2 in the image further above. As the water of the Arctic Ocean gets warmer, the danger increases that heat will reach hydrates at the seafloor and that this will trigger release of huge amounts of methane, in an additional self-reinforcing feedback loop that will make warming in the Arctic accelerate further and that threatens to escalate into a third kind of warming, i.e. runaway warming. Peter Wadhams co-authored a study that calculated that methane release from the seafloor of the Arctic Ocean could yield 0.6°C warming of the planet in 5 years (see video at earlier post).


As above image shows, methane on July 8, 2016, reached levels as high as 2655 ppb. Such high levels typically occur due to methane hydrates getting destabilized. As the sea ice disappears, the situation could get worse rapidly, as illustrated by the images below.

July 5, 2016, sea surface was as warm as 17.1°C / 62.7°F at green circle, i.e. 13.7°C / 24.7°F warmer than 1981-2011. 
These high sea surface temperature anomalies are the result of warmer water getting carried by the Gulf Stream below the sea surface of the Atlantic Ocean into the Arctic Ocean. The water carried into the Arctic Ocean is both warmer and saltier than the water at the surface, as the fresh cold meltwater forms a lid at the surface. At areas around Svalbard where the sea is rather shallow, the warmer water comes to the surface. These high anomalies thus indicate how much warmer the water now is that is entering the Arctic Ocean, as discussed in earlier posts such as this one.
image from previous post
The rapid recent rise in ocean heat is illustrated by above image, showing that oceans on the Northern Hemisphere in May 2015 through April 2016 were 0.93°C warmer than the 20th century average, whereas for the equivalent 2012 period the anomaly was merely 0.46°C. In other words, there now is more ocean heat, making the possibility of methane hydrates destabilization more threatening.

Meanwhile, the speed at which the Arctic is warming is changing the jet streams, as discussed by Paul Beckwith in the video below, following Paul's earlier video that's included in an earlier post.



There are many indications that changes to the climate are accelerating, causing extreme weather events to hit with increasing strength and intensity. Water vapor is a potent greenhouse gas and for each degree Celsius that temperatures rise, the atmosphere can hold 7% more water vapor, which will also lead to stronger storms such as cyclones. On the image below, typhoon Nepartak is approaching Taiwan, with wind speed as high as 103 mph or 165 km/h, and with cloud water as much as 9 kg per square m on July 7, 2016.

Nepartak approaching Taiwan on July 7, 2016, with wind speed as high as 103 mph or 165 km/h (left panel), and with cloud water as much as 9 kg per square m (right panel)
NASA image
According to NASA, very powerful storms near the center of Nepartak's circulation were found to be dropping rain at a rate of over 193 mm (7.6 inches) per hour. Tall thunderstorms called "hot towers" were found to reach heights of 17.0 km (about 10.5 miles).

The image on the right shows a thermal image of Typhoon Nepartak on July 7 at 17:45 UTC. The colder the cloud tops, the higher they are in the troposphere and the stronger the storms.

On July 7, 2016, at 1500 UTC, Nepartak's maximum sustained winds had reached 150 knots (172.6 mph/ 277.8 kph), generating waves as high as 48 feet (14.6 meters).

Strong storms can bring water vapor high 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.

Altogether, the combined global temperature rise due to global warming and feedbacks could exceed 10°C or 18°F within a decade, as discussed in previous posts such as this one.

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


Links

- The North Geographic Pole, the North Magnetic Pole and the North Geomagnetic Pole
http://wdc.kugi.kyoto-u.ac.jp/poles/polesexp.html

- Three Kinds of Warming in the Arctic
http://arctic-news.blogspot.com/2016/02/three-kinds-of-warming-in-arctic.html

- NASA: Napartak (July 9, 2016)
https://www.nasa.gov/feature/goddard/2016/napartak-nw-pacific-ocean

- Jim Pettit Climate Graphs
http://iwantsomeproof.com/3d/siv-ds-weekly-3d.asp


4 comments:

  1. Hello Sam
    I'm quite sure I read this from David Spratt at http://www.climatecodered.org/ : each degree of warming produces enough water vapor to rise temperatures by one more degree ;
    I'm not sure how fast this happens, but it must be a quick response to warming.
    Can you please confirm?
    Thank you.

    Jack

    ReplyDelete
    Replies
    1. The post adds a link to an earlier post that mentions that, according to the IPCC, "water vapour feedback acting alone approximately doubles the warming from what it would be for fixed water vapour. Furthermore, water vapour feedback acts to amplify other feedbacks in models, such as cloud feedback and ice albedo feedback. If cloud feedback is strongly positive, the water vapour feedback can lead to 3.5 times as much warming as would be the case if water vapour concentration were held fixed".

      The water vapor feedback goes pretty much hand in hand with other climate forcers, so the combined temperature rise due to global warming and feedbacks could exceed 10°C or 18°F within a decade. The situation is dire and calls for comprehensive and effective action as described in the Climate Plan.

      Delete
    2. Thank you Sam
      I did translate the article you talk about the potential for a 10°C rise in 10 years, a 2°C rise is already a very scary scenario over 10 years...
      It's really accelerating nowadays.

      Take care
      Jack

      Delete
  2. " . . . feedbacks could exceed 10°C or 18°F within a decade. The situation is dire . . .".

    The word "dire" does not quite do it.

    10°C within a decade is not dire, it's terminal - or terminal for most.

    Seems that the Department of Defense gets it, as minimally reported.
    Worst case scenario - the planet supports 400 million homo sapien sapiens.
    It's been as hot as that, with ample wildlife and natural vegetation.

    But at 10°C, grain agriculture will have gone.
    And the world's human population was pumped up on grain agriculture as the expense of everything else.

    ReplyDelete