Friday, 20 July 2018

Arctic sea ice update - 07/19/2018

Update on Arctic sea ice - 07/19/2018

This graphic from the NSIDC from today shows what is not immediately obvious from an uniformed perusal of the satellite pictures (below): that is that there is very little ice that is at full 100% concentration and large areas are at 50% concentration in large areas.

This a satellite view of the same area - also from today.

Margo goes through the data in a way that is easily intelligible to non-experts like myself.  She demonstrates that a 'hole' in the ice identified some days ago was in fact what it seemed.


This is the view from Climate Reanalyzer


Here is a 300 foot iceberg passing through a Greenland town a couple of days ago.

This is the data on methane emissions at surface level from today. There is nowhere on the planet that has emissions much lower than 1800 ppb. The emissions from Britain and Scandinavia are almost off the chart.

If you are in any doubt about rising levels of methane see this historical chart of emissions.

I have lost the desire to follow this process in great detail but with rapidly-declining sea ice thickness it is not difficult to imagine that what remains will disappear very quickly, whether this season or next.

Sam Carana has demonstrated clearly how sea ice volume has declined year-on-year in an almost unbroken progression

For me there are two key concepts (in addition to the exponential function) to keep in mind.

The first is latent heat:

This is expressed very clearly by Sam Carana:

Latent heat can make such disappearance come abruptly and - for people who only look at changes in extent - rather unexpectedly.

Latent heat is energy associated with a phase change, such as the energy absorbed by solid ice when it changes into water (melting). During a phase change, the temperature remains constant.

Sea ice acts as a buffer that absorbs heat, while keeping the temperature at zero degrees Celsius. As long as there is sea ice in the water, this sea ice will keep absorbing heat, so the temperature doesn't rise at the sea surface.

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.

A very useful practical experiment to illustrate the proccess is to put some ice cubes in water and bring it slowly to the boil. What you will find is that the water stays at the same temperature when heat is applied until all the ice has melted. 

From there the temperature of the water rises very rapidly.

Once the ice has gone, if only for a few weeks a number of positive feedbacks get triggered – primarily the loss of albedo and the release of methane from the shallow water column in the ESAS.

The second concept is that of loss of habitat for humans and other species with rapid warming that has been identified (almost solely) by Guy McPherson. It is not the amount of warming but the rate of warming that presents such challenges for our ability to feed ourselves. 

A perusal of recent headlines should bear this out:

Report: US winter wheat forecast down amid drought

A government report shows U.S. farmers are expected to harvest their smallest winter wheat crop in more than a decade amid an ongoing drought that has devastated fields across the nation's breadbasket and a global surplus of the grain that has depressed prices.

Europe's Blistering Heatwave Is Ruining This Year's Harvest 

  • EU grain growers brace for smallest harvest in six years

  • It looks like a desert out there,’ German farmer says

See my report on Europe from a few days ago.

If crop failures in Europe and America are not enough to worry about we have this headline.

Wheat production in Russia is expected to drop to 67.4 million tonnes this year, down 21.5 percent from a record 2017 crop, after adverse weather affected both winter and spring wheat, French consultancy Agritel said on Thursday.

It takes little imagination and a little intellectual honesty to acknowledge that if we get simultaneous crop failures then we are in deep trouble and that the melting of the Arctic ice and rapid warming will lead to the collapse of the whole economy in a scenario that is laid out with frightful clarity by Guy McPherson.

The president of Finland expresses things in a way that no other political leader will

In this context all I can say is "brace for impact" !

No comments:

Post a Comment