Tuesday, April 17, 2018

Heat Storm

[ click on images to enlarge ]
Arctic sea ice extent has been at a record low for the time of year for most of 2018, as illustrated by above image. In 2012, extent went below 3.4 million km². The question is what minimum 2018 extent will be.

Arctic sea ice could disappear altogether in 2018. Have a look at the progressive loss of sea ice volume depicted in the image on the right, from an earlier post. Zero sea ice volume by 2018 is within the margins of the trend line contained in the data going back to 1979.

What drives volume decline is the combination of extent loss and especially thickness loss. Sea ice thickness has declined particularly where the ice once was at its thickest, i.e. north of Greenland and the Canadian Arctic Archipelago.

The combination image below shows the decline of the thicker sea ice, by comparing sea ice thickness on April 15 (run April 14) for the years 2015 through to 2018, showing that sea ice this year is entering the melting season with little or no thick sea ice left north of Greenland and the Canadian Arctic Archipelago to cope with the influx of warmer water.


The image below shows how much Bering Strait sea ice is at a historic low and the associated International Arctic Research Center post describes that this is caused by higher ocean temperatures and frequent storms.


The influx of warm water from the Atlantic Ocean and from the Pacific Ocean is melting the sea ice from below, while sunlight is melting the sea ice from above. Furthermore, warm water from rivers that end in the Arctic Ocean also contribute to melting of the sea ice, and there are numerous feedbacks that can dramatically speed up melting.

Disappearance of the sea ice means that the buffer that until now has consumed huge amounts of heat, will be gone and that heat that previously went into melting the sea ice, will instead warm up the Arctic.

Sea ice can be expected to continue its downward spiral, given the continued rise of the temperature of the sea surface in the North Atlantic Ocean and the North Pacific Ocean, as illustrated by the image below.


The sea surface is not necessarily the place where the water is at its warmest. This is illustrated by the image below, showing subsurface ocean heat in the area most relevant to El Niño/La Niña events.


[ click on images to enlarge ]
Indeed, while we're currently still in a La Niña period, it looks like a new El Niño will arrive this summer, as illustrated by the forecast plumes on the right.

This could result in a heat storm in which heat waves could decimate the sea ice, while storms could push the remaining sea ice out of the Arctic Ocean.

This danger is further illustrated by the trend line in the image below, a trend that is contained in NASA LOTI data up to March 2018, adjusted by +0.79°C to better reflect the rise from preindustrial and surface air temperatures, and to better include Arctic temperatures.


[ click on images to enlarge ]
The temperature rise in the Arctic is causing decline of the sea ice extent as well as the extent of the snow cover on land.

The image on the right shows the progressive decline of the spring snow cover on land in the Northern Hemisphere.

A recent study shows that the amount of water melt from the glaciers on Mt. Hunter, Alaska, is now 60 times greater than it was before 1850.

Heat waves combined with strong rainfall due to storms could devastate the snow cover in 2018.

Decline of the snow and ice cover in the Arctic comes with a huge loss in albedo, which means that huge amounts of sunlight that were previously reflected back into space instead get absorbed by the Arctic.

The Buffer has gone, feedback #14 on the Feedbacks page
A rapid rise in temperatures in the Arctic will also accelerate changes to jet stream, which can cause huge amounts of heat from the Atlantic Ocean and the Pacific Ocean to enter the Arctic Ocean, further speeding up the temperature rise and threatening to destabilize methane hydrates in sediments under the Arctic Ocean.

The methane will initially be felt most strongly in the Arctic, further speeding up the temperature rise that is already accelerating due to the loss of the snow and ice cover in the Arctic, which makes that less sunlight is reflected back into space and instead adds to warming up the Arctic.

All this shouldn't come unexpected. In the video below, Guy McPherson warns that a rapid temperature rise will affect agriculture across the globe, threatening to cause a collapse of industrial civilization, in turn resulting in an abrupt halt of the sulfates that are currently co-emitted as a result of burning fuel, which will further add to a temperature rise that is already threatening to cause people across the globe to perish at massive scale, due to heatstroke, dehydration and famine, if not perish due to nuclear radiation and further toxic effects of war, as people fight over who controls the last habitable places on Earth.


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

Links

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Feedbacks in the Arctic
https://arctic-news.blogspot.com/p/feedbacks.html

• How much warmer is it now?
https://arctic-news.blogspot.com/2018/04/how-much-warmer-is-it-now.html

• Extinction
https://arctic-news.blogspot.com/p/extinction.html

• Ten Dangers of Global Warming
https://arctic-news.blogspot.com/p/ten-dangers-of-global-warming.html

• Methane Erupting From Arctic Ocean Seafloor
https://arctic-news.blogspot.com/2017/03/methane-erupting-from-arctic-ocean-seafloor.html

• Warning of mass extinction of species, including humans, within one decade
https://arctic-news.blogspot.com/2017/02/warning-of-mass-extinction-of-species-including-humans-within-one-decade.html

• In the coastal communities near the Bering Strait, a winter unlike the rest
https://www.climate.gov/news-features/features/coastal-communities-near-bering-strait-winter-unlike-rest

• A 400‐Year Ice Core Melt Layer Record of Summertime Warming in the Alaska Range 

Monday, April 2, 2018

How much warmer is it now?

The IPCC appears to be strongly downplaying the amount of global warming that has already occurred and that looks set to eventuate over the next decade or so, according to a leaked draft of the IPCC 'Special Report on 1.5°C above pre-industrial'. The 'First Order Draft of the Summary for Policy Makers' estimates that the global mean temperature reached approximately 1°C above pre-industrial levels around 2017/2018.

Let's go over the numbers step by step, by following the image below line by line (click on the image to enlarge it).

NASA's data for the two most recent years for which data are available (2016/2017) show a warming of 0.95°C when using a baseline of 1951-1980 and a warming of 1.23°C when using a baseline of 1890-1910 (left map on image below). In other words, using this earlier baseline results in an additional 0.28°C rise. When using an even earlier baseline, i.e. 1750 or preindustrial, it could be 1.53°C warmer, as discussed in an earlier post.


In other words, merely changing the baseline to preindustrial, as agreed to at the Paris Agreement, can show that we're already above the 1.5°C guardrail that the Paris Agreement had pledged we should not cross.

There's more! As a recent publication points out, most methods that calculate the global temperature use sea surface temperatures. However, doesn't it make more sense to calculate the temperature of the air just above the sea surface? Measuring air temperature at the surface is done in the case of temperatures over land, where one doesn't measure the temperature of the soil or rocks when telling people how warm it is. Since air surface temperatures are slightly higher than sea surface temperatures, the result of looking at air surface temperatures across the globe would be a temperature that is approximately 0.1°C warmer. Furthermore, many areas in the Arctic may not have been adequately reflected in the global temperature, e.g. because insufficient data were available. Since the Arctic has been warming much faster than the rest of the world, inclusion of those areas would add another 0.1°C to the rise. Adding this to the above 1.53°C rise makes that it's already 1.73°C (or 3.11°F) warmer than preindustrial.

Another question is over what period measurements should be taken when assessing whether thresholds have been crossed. When focusing on temperatures during specific months, the rise could be much higher than the annual average. So, does it make more sense to look at a monthly peak rather than at a long-term average?

When building a bridge and when calculating what load the bridge should be able to handle, it makes sense to look at peak traffic and at times when a lot of heavy trucks happen to be on the bridge. That makes a lot more sense than only looking at the average weight of cars driving over the bridge during a period of - say - one, two or thirty years.


Accordingly, the right panel of the top image shows numbers for February 2016 when temperature anomalies were particularly high. When looking at this monthly anomaly, we are already 2.37°C (or 4.27°F) above preindustrial, i.e. well above the 2°C guardrail that the Paris Agreement had pledged we should definitely not cross.

Should the temperature rise be calculated using a longer period? The IPCC appears to have arrived at its temperature rise estimate by using an extrapolation or near term predictions of future warming so that the level of anthropogenic warming is reported for a 30 year period centered on today.

The image below, from an earlier post, shows global warming for a 30-year period centered on January 2018, using NASA 2003 to January 2018 LOTI anomalies from 1951-1980, adjusted by 0.59°C to cater for the rise from preindustrial to 1951-1980, and with a polynomial trend added.


If above trendline is adjusted by a further 0.2°C, by shifting to air temperatures instead of sea surface temperatures, and by better reflecting Arctic temperatures, then the trendline looks set to cross the 2°C guardrail in 2018. So, will Earth cross 2°C in 2018?


Above images illustrate the importance of what's going to happen next. The temperature rise up until now may well be dwarfed by what's yet to come and the outlook may well be even worse than what most fear will eventuate. The image below, from an earlier post, shows a steep rise from 2016 to 2026, due to the combined impact of the warming elements listed in the left box of the image below.


Meanwhile, the rise in carbon dioxide levels appears to be accelerating, as illustrated by the images below.


Indeed, despite pledges made at the Paris Agreement to limit the temperature increase to 1.5°C above pre-industrial, the rise in CO₂ since preindustrial, i.e. 1750, still appears to be accelerating.


On March 18, 2018, the sea surface temperature near Svalbard (at the green circle) was 16.7°C or 62.1°F, i.e. 14.7°C or 26.4°F warmer than the daily average during the years 1981-2011.


On March 30, 2018, methane levels as high as 2624 parts per billion were recorded.


On April 1, 2018, methane levels as high as 2744 parts per billion were recorded.



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


Links

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Extinction
https://arctic-news.blogspot.com/p/extinction.html

• How much warming have humans caused?
https://arctic-news.blogspot.com/2016/05/how-much-warming-have-humans-caused.html

• IPCC seeks to downplay global warming
https://arctic-news.blogspot.com/2018/02/ipcc-seeks-to-downplay-global-warming.html

• 2016 well above 1.5°C
https://arctic-news.blogspot.com/2017/01/2016-well-above-1.5c.html

• Interpretations of the Paris climate target, by Andrew Schurer et al.
https://www.nature.com/articles/s41561-018-0086-8