Arctic News: extent

Showing posts with label extent. Show all posts

Monday, July 27, 2020

Arctic sea ice could disappear completely within two months' time

Arctic sea ice fell by 3.239 million km² in extent in 25 days (i.e. from July 1 to 25, 2020). Melting will likely continue for another two months. If it continues on its current trajectory, the remaining 6.333 million km² of Arctic sea ice could disappear completely within two months' time.

The fall in extent over the next two months' time may not remain as as steep as it was in July, yet the sea ice still could disappear completely. One reason for this is that, over the years, sea ice thickness has been declining even faster than extent. The rapid decline in sea ice thickness is illustrated by the sequence of images below.

The image on the right further illustrates that sea ice is getting very thin, which threatens the latent heat tipping point to get crossed.

Sea currents and the Coriolis force will make that the influx of warm, salty water into the Arctic Ocean will continue. With no buffer of sea ice left underneath the surface of the sea ice to absorb incoming ocean heat, more heat will accumulate in the Arctic Ocean, threatening that the methane hydrates tipping point will get crossed.

The navy.mil animation below was run on August 3, 2020, and shows sea ice thickness over 30 days (last 8 frames are forecasts for August 4 - August 11, 2020).

Here's another indication that the buffer is disappearing fast. North of Greenland and of the Canadian Arctic Archipelago, less than 700 km from the North Pole, the sea ice is disappearing, precisely where the thickest sea ice used to be located.

High greenhouse gas levels are causing high temperatures over the Arctic and high ocean temperatures.

On July 25, 2020, sea surface temperatures in the Arctic Ocean were as high as 20.8°C or 69.4°F (at the green circle on above image).

At that same location, on July 22, 2020, sea surface temperatures in the Arctic Ocean were as much as 17°C or 30.5°F higher than the daily average during the years 1981-2011.

This location is where the Pechora River flows into the Barents Sea (the green circle pointed at by the white arrow on above image).

Distortion of the jet stream is causing more extreme weather, resulting in the recent lengthy heatwave over Siberia that has heated up the water of rivers flowing into the Arctic Ocean.

A cyclone was visible over the Arctic Ocean on July 28, 2020, as illustrated by the image on the right.

Underneath on the right is a forecast for August 7, 2020, showing rain over the North Pole.

In summary, Arctic sea ice may disappear completely over the next two months, and there are at least six reasons why this could occur:

• Low Arctic sea ice extent;
• Low Arctic sea ice thickness;
• High ocean temperature;
• High greenhouse gas levels;
• High temperatures over the Arctic;
• Distorted jet stream causing extreme weather such as storms that can break up the sea ice.

As the image below shows, sea surface temperatures in the Arctic Ocean on August 1, 2020, were as much as 11.5°C or 20.7°F higher than 1981-2011 (at green circle, off the coast of Siberia, opposite Greenland).

Ominously, the MetOp-1 satellite recorded peak methane levels of 2933 ppb, at 469 mb, on the afternoon of July 30, 2020.

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

Links

• NSIDC Arctic sea ice
http://nsidc.org/arcticseaicenews

• Polar Portal - sea ice volume
http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-thickness-and-volume

• NASA Worldview
https://worldview.earthdata.nasa.gov

• Arctic Hit By Ten Tipping Points
https://arctic-news.blogspot.com/2020/04/arctic-hit-by-ten-tipping-points.html

• Fast Path to Extinction
https://arctic-news.blogspot.com/2020/06/fast-path-to-extinction.html

• 2020 Siberian Heatwave continues
https://arctic-news.blogspot.com/2020/06/2020-siberian-heatwave-continues.html

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

Wednesday, July 8, 2020

Arctic Sea Ice at Record Low for Time of Year

As temperatures keep rising, should the IPCC raise the alarm?

Some 1,750 jurisdictions in 30 countries have now declared a climate emergency, according to this post dated July 8, 2020. The United Nations does acknowledge the Climate Emergency, but its description is sourced from the IPCC Global Warming of 1.5°C report that was approved back in 2018. A lot has happened since, as described in many posts at Arctic-news. When a state of emergency is declared, doesn't one expect such a declaration to result in action, complete with updates on the effectiveness of the action?

Described below are some events taking place right now.

Arctic Sea Ice at Record Low for Time of Year

Arctic sea ice looks set to reach an all-time record low in September 2020.

In an earlier post, Paul Beckwith describes a Blue Ocean Event (BOE) and some of the consequences of the changes taking place in the Arctic. A BOE occurs when sea ice extent gets below 1 million km², which is important regarding the amount of sunlight absorbed/reflected in the Arctic (albedo feedback).

[ from earlier post ]

Arctic sea ice extent on July 20, 2020, was well below the minimum of the 1979-1990 average (the orange line among the blue lines on the image below).

If it continues on its current trajectory, Arctic sea ice may well be gone altogether in September 2020.

A BOE is one of the many tipping points that threaten to get crossed in the Arctic.

[ click on images to enlarge ]

As illustrated by the image on the right, sea ice is getting very thin, which threatens the latent heat tipping point to be crossed, meaning there is no buffer of sea ice left underneath the surface of the sea ice to absorb ocean heat.

Furthermore, the temperature rise in the Arctic is accelerating and the Arctic Ocean is getting very hot, threatening that the methane hydrates tipping point will get crossed.

The navy.mil animation below run on July 20, 2020, shows the fall in sea ice thickness over 30 days (last 8 frames are forecasts for July 21-28, 2020).

The combination image below illustrates the speed at which Arctic sea ice is disappearing, with sea ice thickness shown in meters from left to right at June 1, June 18, July 1 and July 18, 2020.

Meanwhile, fires and smoke are visible at a distance of as little as 1970 km or 1224 miles from the North Pole.

The image below shows open water on the edge of the sea ice, north of Greenland and the Canadian Archipelago, where the thickest sea ice used to be located.

Alarming acceleration of heating continues

The image below shows the global temperature rise through to June 2020.

[ click on images to enlarge ]

The red trend supports fears that the 2°C above preindustrial threshold has already been crossed this year, while loss of the aerosol masking effect and an emerging El Niño could trigger a huge further temperature rise.

Global temperature anomalies are typically lower in June (yellow circles) than the annual anomaly. The Copernicus image below shows twelve-month averages of global-mean surface air temperature anomalies relative to 1981-2010.

The shape of current anomalies is very similar to the peak reached around 2016. This is alarming because the peak around 2016 was reached under El Niño conditions, whereas the current temperatures are reached under conditions that are leaning toward La Niña, as illustrated by the images below.

In conclusion, one may wonder how much stronger the temperature rise will be once El Niño conditions do arrive.

[ click on images to enlarge ]

Furthermore, one may wonder how much current temperatures are elevated by a decrease in emissions due to COVID-19 restrictions, which in turn makes one wonder how much higher the temperature will be when the aerosol masking effect will fall away even further as the world phases out coal-fired power plants, bunker oil for shipping, etc. Guy McPherson concludes that a 1°C rise in global-average temperature will occur within a few days or weeks after industrial activity is reduced by as little as 20%.

Very high sea surface temperature anomalies in the Arctic Ocean

Sea surface temperature anomalies in the Arctic Ocean are very high. As discussed in a recent post, sea surface temperatures in the Bering Strait were as much as 15.1°C or 27.2°F hotter than 1981-2011 on June 20, 2020 (in Norton Sound, Alaska, at the green circle).

As the image below shows, the sea surface temperature at green circle used to be 0.3°C (32.6°F). It was 12°C (53.6°F) on July 18, 2020.

Much of the Arctic Ocean is quite shallow, making that the water can warm up very quickly during summer heat peaks and heat can reach the seafloor, which comes with the risk that heat will penetrate cracks in sediments at the seafloor. Melting of ice in such cracks can lead to abrupt destabilization of methane hydrates contained in sediments.

Very high peak methane levels

Ominously, as the 2020 Siberian heatwave continues, very high peak methane levels show up over the Arctic Ocean. The NOAA 20 satellite recorded a peak methane level of 2728 ppb at 399 mb on the afternoon of July 16, 2020.

The MetOp-1 satellite recorded a peak methane level of 2726 ppb on the afternoon of July 16, 2020. Also, a mean methane level of 1897 ppb was recorded at 469 mb and a mean methane level of 1908 ppb at 293 mb.

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

Links

• Arctic Data archive System
https://ads.nipr.ac.jp/vishop/vishop-extent.html

• Polar Portal - sea ice volume
http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-thickness-and-volume

• Fast Path to Extinction
https://arctic-news.blogspot.com/2020/06/fast-path-to-extinction.html

• NASA Worldview
https://worldview.earthdata.nasa.gov

• Surface air temperature for June 2020
https://climate.copernicus.eu/surface-air-temperature-june-2020

• ENSO: Recent Evolution, Current Status and Predictions - NOAA, July 6, 2020
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

• Arctic Hit By Ten Tipping Points
https://arctic-news.blogspot.com/2020/04/arctic-hit-by-ten-tipping-points.html

• The Myth of Sustainability - by Guy McPherson
https://opastonline.com/wp-content/uploads/2020/07/the-myth-of-sustainability-eesrr-20.pdf

• 2020 Siberian Heatwave continues
https://arctic-news.blogspot.com/2020/06/2020-siberian-heatwave-continues.html

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

Sunday, November 17, 2019

Arctic Ocean November 2019

On November 16, 2019, there was little sea ice between Greenland and Svalbard. For reference, the image below has been added, showing coastlines for the same area.

The image on the right shows that the average air temperature (2 m) on November 15, 2019, was 4°C higher over the Arctic than during 1979-2000.
Ocean heat is rising up from the Arctic Ocean, while a wavy jet stream enables cold air to leave the Arctic and descend over North America and Eurasia. On November 13, 2019, it was warmer in Alaska than in Alabama.

The image below shows temperatures north of 80°N. The red line on the image shows the 2019 daily mean temperature up to November 16, 2019. The temperature is now well above the 1958-2002 mean (green line). The image also shows the freezing point of fresh water (273.15K, 0°C or 32°F, blue line).

The freezing point for salt water is lower, at around -2°C, or 28.4°F, or 271.2°K. In other words, a rise in the salt content of the water alone can make ice melt, i.e. even when the temperature of the water doesn't rise.

The image below shows that Arctic sea ice volume has been at record low levels for the time of year for some time.

As the image below shows, Arctic sea ice extent in the Chukchi Sea is currently very low.

[ image by Zack Labe, uploaded November 13, 2019 ]

Oceans are absorbing more than 90% of global heating, as illustrated by the image below.

Arctic sea ice used to absorb 0.8% of global heating (in 1993 to 2003). Ocean heat keeps flowing into the Arctic Ocean, carried by ocean currents, as illustrated by the image below.

As peak heat arrives in the Arctic Ocean, it melts sea ice from below. In Summer 2019, a critical tipping point was crossed; ocean heat could no longer find further sea ice to melt, as the thick sea ice that hangs underneath the surface had disappeared. A thin layer of sea ice at the surface was all that remained, as air temperatures remained low enough to prevent it from melting from above.

This indicates that the buffer has gone that has until now been consuming ocean heat as part of the melting process. As long as there is sea ice in the water, this sea ice will keep absorbing heat as it melts, so the temperature will not 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.

The images above and below shows very high sea surface temperature anomalies on the Northern Hemisphere for October 2015 and October 2019. In both cases, anomalies of 1.09°C or 1.96°F above the 20th century average were recorded.

The October 2015 anomaly occurred under El Niño conditions, whereas the equally-high anomaly in October 2019 occurred under El Niño/La Niña-neutral conditions, while another El Niño is likely to come in 2020. In other words, the threat is that even more ocean heat is likely to arrive in the Arctic Ocean in 2020.

The danger is particularly high in October, as Arctic sea ice starts growing in extent at the end of September, thus sealing off the water, meaning that less ocean heat will be able to escape to the atmosphere. This increases the danger that hot water will reach sediments at the Arctic Ocean seafloor and trigger massive methane eruptions.

Concentrations of carbon dioxide (CO₂, 407.8 ppm), methane (CH₄, 1869 ppb) and nitrous oxide (N₂O, 331.1 ppb) in 2018 surged by higher amounts than during the past decade, the WMO said in a recent news release and as illustrated by the image on the right, which shows that CH₄, CO₂ and N₂O levels in the atmosphere in 2018 were, respectively, 259%, 147% and 123% of their pre-industrial (before 1750) levels.

“There is no sign of a slowdown, let alone a decline, in greenhouse gases concentration in the atmosphere despite all the commitments under the Paris Agreement on Climate Change,” said WMO Secretary-General Petteri Taalas.

“It is worth recalling that the last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago. Back then, the temperature was 2-3°C warmer, sea level was 10-20 meters higher than now,” said Mr Taalas.

Global methane levels are very high. Mean global methane levels were as high as 1914 parts per billion on September 3, 2019, as discussed in a recent post. Peak methane levels as high as 2961 parts per billion were recorded by the MetOp-2 satellite on October 24, 2019, in the afternoon at 469 mb.

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

In the video below, Paul Beckwith discusses Arctic sea ice.

Monday, October 14, 2019

Arctic Ocean October 2019

Above image shows temperatures north of 80°N. The red line on the image shows the 2019 daily mean temperature up to Oct 13, 2019. The temperature is now well above the 1958-2002 mean (green line). The image also shows the freezing point of fresh water (273.15K, 0°C or 32°F, blue line).

The freezing point for salt water is lower, at around -2°C, or 28.4°F, or 271.2°K. In other words, a rise in the salt content of the water alone can make ice melt, i.e. even when the temperature of the water doesn't rise.

Above combination image shows forecasts for October 26, 2019. The left panel shows that air temperatures (2 m) are forecast to be 5.4°C higher over the Arctic than 1979-2000. Parts of the Arctic Ocean where there is no sea ice are forecast to be especially hot, since this is where heat gets transferred from the Arctic Ocean to the atmosphere. Anomalies are as high as 30°C, the top end of the scale. Temperature anomalies are in line with changes to the Jet Stream, as illustrated by the forecast in the right panel.

As above image shows, there was very little sea ice north of Greenland on October 11, 2019. Arctic sea ice extent is very low. As the image below shows, Arctic sea ice extent was 4.88 million km² on October 13, 2019, the lowest on record for the time of year.

[ click on image to enlarge ]

As the image below shows, the heat rising from the Arctic Ocean is such that sea ice extent is hardly growing.

The image below shows Arctic sea ice extent for the years, 1980,1990, 2010, 2012 and 2019, for the period as indicated.

The image below indicates that Arctic sea ice volume has been at record low levels for the time of year for some time.

Rising temperatures of water in the Arctic Ocean cause the sea ice to melt away from below. The image below, created with NOAA 2007-2019 June-September sea surface temperature data, shows heating of the sea surface on the Northern Hemisphere, with an ominous trend added.

The image indicates that a critical tipping point was crossed this year, with the disappearance of the thick sea ice that hangs underneath the surface.

[ click on image to enlarge ]

The situation is so precarious because hot, salty water keeps flowing into the Arctic Ocean, at a time of year when the sea ice is growing in extent and sealing off the surface of the Arctic Ocean, thus reducing the heat that can get transferred to the atmosphere.

How hot is that water flowing into the Arctic Ocean? The image on the right shows sea surface temperature anomalies. On October 13, 2019, the sea surface near Svalbard at the green circle was 18.3°C or 65°F, i.e. 14.7°C or 26.4°F hotter than 1981-2011.

This is an indication of how hot the water is underneath the sea surface. At the sea surface, water gets colder due to evaporation and rain, resulting in a lid of fresh water at the surface sealing off hot and salty water underneath.

This hot and salty water moves underneath the sea surface in line with the deeper parts of the ocean, to emerge at this area near Svalbard (marker in the image below), as the water at this area becomes more shallow, making the sea current push the water to the surface.

Back in 2011, a study by Micha Ruhl et al. pointed at huge methane releases from clathrates during the end-Triassic mass extinction event, as discussed in an earlier post. The danger is that, in the absence of thick sea ice, hot water with a high salt content will reach the seafloor of the Arctic Ocean, making it easier for ice in cracks in sediments at the seafloor to melt, resulting in huge methane releases.

[ from an earlier post ]

Ominously, methane levels as high as 2961 parts per billion were recorded by the MetOp-2 satellite on October 24, 2019, in the afternoon at 469 mb.