As illustrated by above map, Arctic heating is accelerating, with temperatures showing up in the Arctic that are up to 4.41°C hotter than the average global temperature during 1880-1920.
The image below shows two plots. On the left-hand side is the temperature plot associated with above map, had a monthly mean been selected. To smooth the data, a 4-year running mean was chosen, and the plot on the right-hand side shows the associated global mean anomalies. Note that, due to this smoothing, only data from 1882 to August 2017 are displayed in the plot of the right-hand side.
It is appropriate to adjust the data by 0.5°C, as follows:
An adjustment of 0.3°C to reflect a pre-industrial baseline (heating occurred due to people's emissions before 1880-1920);
An adjustment of 0.1°C to reflect air temperatures over oceans (as opposed to sea surface temperatures);
An adjustment of 0.1°C to better include polar temperatures (the top and bottom of the image at the top shows large polar areas that should not be excluded, the more so since the Arctic has the highest temperature anomalies).
The image below shows both adjusted and unadjusted data as dark blue lines, with a light-blue polynomial trend added over the adjusted data.
Such a trend can further smooth out seasonal differences and El Niño/La Niña variability.
Such a trend can also show the potential for further temperature rise in the near future, which can constitute an important warning.
This is particularly important as the trend shows that we could be crossing the 2°C guardrail this year, i.e. the threshold that was too dangerous to be crossed.
What is the danger? Arctic heating is accelerating, as the image at the top shows, and this could make global temperatures skyrocket in a matter of years. Where Arctic sea ice disappears, hot water emerges due to albedo changes and loss of the buffer that has until now been consuming heat as part of the melting process. This is illustrated by the image below showing the sea surface temperature difference from 1961-1990 in the Arctic at latitudes 60°N - 90°N on August 23, 2019.
Disappearance of Arctic sea ice comes with numerous feedbacks that further speed up the heating, as described in the recent post Arctic Sea Ice Gone By September 2019?. Heatwaves can strongly heat up the water that gets carried by rivers into the Arctic Ocean. As the image below shows, the water was as hot as 10.7°C or 51.3°F at green circle on August 20, 2019, i.e. 9.4°C or 16.9°F hotter than 1981-2011.
As the Arctic is heating up faster than the rest of the world, the Jet Stream gets more and more distorted. A cyclone is forecast over the Arctic Ocean for August 24, 2019, pulling hot air over the Arctic Ocean, resulting in temperatures at the green circle as high as 10.4°C or 50.6°F at 1000 hPa and 7.4°C or 45.2°F at surface level, as the image below shows.
The image below illustrates the distortion of the Jet Stream, moving over the Arctic Ocean on August 24, 2019.
Such a cyclone can pull huge amounts of hot air over the Arctic Ocean, while it can also devastate the sea ice with the destructive power of winds, rain and hail.
As above animation shows, Arctic sea ice is very thin and vulnerable at the moment. The cyclone also looks set to batter the sea ice at a time when huge amounts of ocean heat are entering the Arctic Ocean from the Atlantic and Pacific Oceans. More ocean heat looks set to be on the way. As the image below shows, sea surface temperatures around North America were as high as 33°C or 91.4°F on August 21, 2019.
The image below shows the worrying rise of Northern Hemisphere sea surface temperature anomalies from the 20th century average, with the added trend illustrating the danger that this rise will lead to Arctic sea ice collapse and large methane eruptions from the seafloor of the Arctic Ocean, further accelerating the temperature rise.
Andrew Glikson Earth and Climate scientist Australian National University 12-8-2019
Preamble
The inhabitants of planet Earth are in the process of destroying the habitability of their world through the perpetration of the largest mass extinction of species since 66 million years ago, when a large asteroid impacted Earth, and 55 million years since the Paleocene-Eocene Thermal Maximum (PETM) reaching 5–8°C. The late Holocene-Anthropocene climate change represents an unprecedented event, triggering a fast shift in climate zones and a series of extreme weather events, with consequences for much of nature and civilization. The changes are manifest where green forests are blackened by fire, droughts are turning grassy planes to brown semi-deserts, brilliant white snow and ice caps are melting into pale blue water and clear blue skies turn grey due to aerosols and jet contrails, most particularly in the northern hemisphere. Unless effective efforts are undertaken at CO₂ drawdown, the consequence would include demise of much of nature and a collapse of human civilization.
1. The scorched Earth
The transfer of hundreds of billions of tonnes of carbon from the Earth crust, the residues of ancient biospheres, to the atmosphere and oceans, condemning the bulk of life through the most extreme shift in the composition of the atmosphere and ocean Earth has experienced since 55 million years ago, with changes taking place in front of our eyes. Since the industrial revolution, about 375 billion tonnes of carbon (or 1,374 billion tonnes CO₂) have been emitted by humans into the atmosphere. The consequences are everywhere, from mega-droughts, to heat waves, fires, storms and floods. With atmospheric CO₂-equivalent rising above 500 ppm and mean temperatures by more than 1.5°C (Figure 1) look no further than the shift in climate zones, displayed for example on maps of the expanding wet tropical zones, drying sub-tropical latitudes and polar-ward migration of temperate climate zone. The ice sheets and sea ice are melting, huge fires overtake Siberia, the Sahara is shifting northward, large parts of southern Europe are suffering from droughts, heat waves and fires, the Kalahari Desert dunes are shifting and much of southern Australia is affected by warming and draughts. This is hardly compensated by a minor increase in precipitation and greening such as at the southern fringes of the Sahara Desert and parts of northern Australia.
Induced by anthropogenic carbon emissions reaching 37.1 billion tonnes CO₂ in 2018 and their amplifying feedbacks from land and oceans and, ranging from 16.5 tonnes CO₂ per capita per year from the US to 35.5 tonnes CO₂ per capita per year from Saudi Arabia and 44 tonnes CO₂ per capita per year from Australia, the inexorable link between these emissions and the unfolding disaster is hardly mentioned by mainstream political classes and the media.
Figure 1 (A) Growth of CO₂-equivalent level and the annual greenhouse gas Index (AGGI¹). Measurements of CO₂ to
the 1950s are from (Keeling et al., 1958) and air trapped in ice and snow above glaciers. Pre-1978 changes are based
on ongoing measurements of all greenhouse gases. Equivalent CO₂ amounts (in ppm) are derived from the relationship
between CO₂ concentrations and radiative forcing from all long lived gases; (B) showing how much warmer each
month of the GISTEMP data is than the annual global mean. For July (2019) temperatures rose by about +1.5°C.
¹The AGGI index uses 1990 as a baseline year with a value of 1. The index increased every year since 1979.
2. Migrating climate zones
As the globe warms, to date by a mean of near ~1.5 °C, or ~2.0°C when the masking effects of sulphur dioxide and other aerosols are considered, and by a mean of ~2.3°C in the polar regions, the expansion of warm tropical latitudes and the pole-ward migration of subtropical and temperate climate zones (Figure 2) ensue in large scale droughts such as parts of inland Australia and southern Africa. A similar trend is taking place in the northern hemisphere where the Sahara desert is expanding northward, with consequent heat waves across the Mediterranean and Europe.
In southern Africa “Widespread shifts in climate regimes are projected, of which the southern and eastern expansion of the hot desert and hot steppe zones is most prominent. From occupying 33.1 and 19.4 % of southern Africa under present-day climate, respectively, these regions are projected to occupy between 47.3 and 59.7 % (hot desert zone) and 24.9 and 29.9 % (hot steppe zone) of the region in a future world where the mean global temperature has increased by ~3°C.
Closely linked to the migration of climate zones is the southward drift of Antarctic- sourced cold moist fronts which sustain seasonal rain in south-west and southern Australia. A feedback loop has developed where deforestation and decline in vegetation in southern parts of the continent result in the rise of thermal plumes of dry air masses that deflect the western moist fronts further to the southeast.
Figure 2. Köppen-Geiger global Climate zones classification map
Since 1979 the planet’s tropics have been expanding pole-ward by 56 km to 111 km per decade in both hemispheres, leading one commentator to call this Earth’s bulging waistline. Future climate projections suggest this expansion is likely to continue, driven largely by human activities – most notably emissions of greenhouse gases and black carbon, as well as warming in the lower atmosphere and the oceans.”
An analysis of the origin of Australian droughts suggests, according to both observations and climate models, that at least part of this decline is associated with changes in large-scale atmospheric circulation, including shrinking polar ice and a pole-ward movement of polar-originated westerly wind spirals, as well as increasing atmospheric surface pressure and droughts over parts of southern Australia (Figure 3). Simulations of future climate with this model suggest amplified winter drying over most parts of southern Australia in the coming decades in response to changes in radiative forcing. The drying is most pronounced over southwest Australia, with total reductions in austral autumn and winter precipitation of approximately 40% by the late twenty-first century. Thus rainfall in southwestern Australia has declined sharply from about 1965 onward, concomitant with the sharp rise of global temperatures.
Figure 3 (A) Bureau of Meteorology (BOM) drought map, showing rainfall levels for the southern wet season from
April 1 to July 31 in 2019; (B) NASA satellite image displaying a southward deflection of Antarctic-sourced moist
cold fronts from southern Australia, a result of (1) southward migration of climate zones; (2) increasing aridity of
southern and southwestern Australia due to deforestation; (3) rising hot plumes from warming arid land.
3. Extreme weather events
The consequences of the migration of climate zones are compounded by changes in flow patterns of major river systems around the world, for example in southern an southeastern Asia, including the Indus, Ganges, Brahmaputra and Mekong river basins, the home and bread basket for more than a billion people. With warming, as snow cover declines in the mountainous source regions of rivers, river flows are enhanced, with ensuing floods, in particular during the Monsoon. For example, in 2010 approximately one-fifth of Pakistan's total land area was affected by floods (Figure 4A), directly affecting about 20 million people, with a death toll close to 2,000. And about 700 people in cyclone Isai in Mozambique (Figure 4B, C). Such changes in climate and geography are enhanced once sea level rise increases from the scale of tens of centimeters, as at present, to meters, as predicted to take place later this and next century.
An increasing frequency and intensity of cyclones constitute an inevitable consequence of rising temperatures over warm low pressure cell tracks in tropical oceans, already affecting large populations in the Caribbean and west Pacific island chains, encroaching into continental coastal zones, China, southeast USA, southeast Africa, India, northern Australia, the Pacific islands. According to Sobel et al. (2016)“We thus expect tropical cyclone intensities to increase with warming, both on average and at the high end of the scale, so that the strongest future storms will exceed the strength of any in the past”. Likewise increasing temperatures, heat waves and droughts, compounded by deforestation over continents, constitute an inevitable consequence of heat waves and droughts. A prime example is the Siberian forest fires (Figure 5B), covering an area larger than Denmark and contributing significantly to climate change. Since the beginning of the year a total of 13.1 million hectares has burned. Total losses from natural catastrophes on 2018 stated as US$160 billion.
Figure 4 (A) Pakistan flooding, shows the 2010 Indus River spanning well over 10 kilometers, completely filling
the river valley and spilling over onto nearby land. Floodwaters have created a lake almost as wide as the swollen
Indus that inundates Jhatpat; (B) Before-and-after satellite imagery of Mozambique showing massive flood
described as an "inland ocean" up to 30 miles wide following the landfall of Tropical Cyclone Idai, 2019.
Figure 5 (A) Global fire zones, NASA. The Earth data fire map accumulates the locations of fires detected by
moderate-resolution imaging radiometer (MODIS) on board the Terra and Aqua satellites over a 10-day period.
Each colored dot indicates a location where MODIS detected at least one fire during the compositing period. Color ranges from red where the fire count is low to yellow where number of fires is large; (B) An ecological
catastrophe in Russia: wildfires have created over 4 million square km smoke lid over central northern Asia.
Big Siberian cities are covered with toxic haze that had already reached Urals.
4. Shrinking Polar ice sheets
Last but not least, major changes in the Polar Regions are driving climate events in the rest of the globe. According to NOAA Arctic surface air temperatures continued to warm at twice the rate of the rest of the globe, leading to major thaw at the fringes of the Arctic (Figure 6A) and a loss of 95 percent of its oldest ice over the past three decades. Arctic air temperatures during 2014-18 since 1900 have exceeded all previous records and are driving broad changes in the environmental system both within the Arctic as well as through the weakening of the jet stream which separates the Arctic from warmer climate zones. The recent freezing storms in North America represent penetration of cold air masses through an increasingly undulating jet stream barrier, as well as allowing warm air masses to move northward, further warming the Arctic and driving further ice melting (Figure 6B).
According to Rignot et al. (2011) in 2006 the Greenland and Antarctic ice sheets experienced a combined mass loss of 475 ± 158 billion tons of ice per year. IPCC models of future climate change contain a number of departures from the paleoclimate evidence, including the major role of feedbacks from land and water, estimates of future ice melt, sea level rise rates, methane release rates, the role of fires in enhancing atmospheric CO₂, and the already observed onset of transient freeze events consequent on the flow of ice melt water into the oceans. Ice mass loss would raise sea level on the scale of meters and eventually tens of meters (Hansen et al. 2016). The development of large cold water pools south and east of Greenland (Rahmstorf et al. 2015) and at the fringe of West Antarctica, signify early stages in the development of a North Atlantic freeze, consistent with the decline in the Atlantic Meridional Ocean Circulation (AMOC). As the Earth warms the increase in temperature contrasts across the globe, in particular between warming continental regions and cooling ocean regions, leads to storminess and extreme weather events, which need to be taken into account when planning adaptation measures, including preparation of coastal defenses, construction of channel and pipelines from heavy precipitation zones to drought zones.
Figure 6 (A)Thawing at the fringes of Siberia and Canada. Scientists say 2019 could be another annus
horribilis for the Arctic with record temperatures already registered in Greenland—a giant melting ice
sheet that threatens to submerge the world's coastal areas one day; (B) Weakening and increasing undulation of the polar vortex, allowing penetration of cold fronts southward and of warm air masses northward.
Figure 7 (A) Surface air temperature (°C) change in 2055–2060 relative to 1880–1920 according to.
A1B model + modified forcings and ice melt to 1 meter sea level rise; (B) Surface-air temperature
change in 2096 relative to 1880–1920 according to IPCC model AIB adding Ice melt with 10-year
doubling of ice melt leading to +5 meters sea level rise; (C) Surface air temperature (°C) relative to
1880–1920 for several scenarios taking added ice melt water into account (Hansen et al. 2016)
Postscript
None of the evidence and projections summarized above appears to form a priority consideration on the part of those in power—in parliaments, in corporations, among the wealthy elites and vested interests. Having to all intents and purposes given up on the habitability of large parts of the Earth and on the survival of numerous species and future generations—their actions and inactions constitute the ultimate crime against life on Earth.
Andrew Glikson
Dr Andrew Glikson
Earth and climate scientist Australian National University Canberra, Australian Territory, Australia
geospec@iinet.net.au
Books:
The Archaean: Geological and Geochemical Windows into the Early Earth
The IPCC has just issued a special report Climate Change and Land, on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems. In its new report 'Climate Change and Land', the IPCC finds that vegan is the best diet to reduce emissions. Sadly, it is yet another missed opportunity to show some integrity.
[ click on image to enlarge ]
Indeed, little or nothing will change as long as the IPCC keeps downplaying the dire situation we're in.
As an example, the IPCC Report uses a very low value of 28 as Global Warming Potential (GWP) for methane, which is totally inappropriate and unacceptable given the rapidity at which the biosphere is deteriorating, given the accelerating pace at which extreme weather events are striking the land all around the world, and given the grim prospects for people worldwide in the absence of rapid and radical change.
The report finds that agriculture, forestry and other land use activities accounted for around 13% of carbon dioxide, 44% of methane, and 82% of nitrous oxide emissions from human activities globally during 2007-2016, representing 23% of total net anthropogenic emissions of greenhouse gases. If emissions associated with pre- and post-production activities in the global food system are included, the emissions could be as high as 37% of total net anthropogenic greenhouse gas emissions.
The Report adds an image showing that annual methane emissions from agriculture had reached some 4Gt CO₂eq in 2016. The IPCC notes that this 4Gt for methane's CO₂-eq is based on a GWP for methane of 28 over 100 years and without climate-carbon feedbacks, taken from its Fifth Assessment Report (AR5), published in 2014.
As said, the Report calculates that net greenhouse gas emissions from agriculture, forestry, and other land use were 23% of people's 2007-2016 emissions when using a GWP of 28 for methane. When using a GWP of 150, that share rises to 31%, as illustrated by the image on the right.
Instead of calculating methane's GWP over 100 years, a very short horizon is appropriate. Moreover, research published in 2016 and 2018 had already found methane to be more potent than IPCC's GWP for methane in AR5, as discussed in a recent post.
When using an appropriate GWP, the percentage of greenhouse gases coming from agriculture (in particular livestock products) increases dramatically, thus rightly highlighting the urgency for governments to act, e.g. by implementing local feebates, such as fees on livestock products and nitrogen fertilizers with revenues used to support soil supplements containing biochar, as recommended in a recent post.
Furthermore, the IPCC should have pointed the finger at the cartel of looters comprising fuel, meat, chemical and pharmaceutical industries and fuel-powered vehicle manufacturers and utilities that finances corrupt politicians and that goes hand in glove with a military-industrial complex that feeds on manufacturing conflict over resources that are the very cause of the wrath of pollution.
The situation is dire and calls for comprehensive and effective action, as described in the Climate Plan.
The July 2019 temperature was on a par with, and possibly marginally higher than, that of July 2016, according to a World Meteorological Organization (WMO) news release pointing an image by the Copernicus Climate Change Programme that is used as the background for above image.
Previously, July 2016 was the hottest July on record with a global land and ocean temperature of 16.67°C (62.01°F), or 3.25°C above the pre-industrial temperature of 13.42°C (56.16°F) and surpassing the record set before that, in July 2015.
The July 2019 Surface Temperature was 16.7°C in real temperatures (as opposed to anomalies), as illustrated by the image on the right, supplied by James Hansen and constructed using Dr. Phil Jones climatology and GISS 250 km smoothing of anomalies.
The image also shows, James Hansen adds, that the monthly mean of the daily mean (not daily maximum) exceeded 35°C (95°F) in parts of North Africa and the Middle East.
The month July typically is the hottest month of the year. July 2019 was 2.34°C (or 4.21°F) hotter than the 1980-2015 annual global mean, and July 2019 was the hottest July on record, making it the hottest month on record to date.
According to NASA data, July 2016 was 2.26°C hotter than the 1980-2015 annual global mean, and August 2016 was actually the previously hottest month on record with 2.31°C above the 1980-2015 annual mean, so August 2019 could be even hotter, which is quite remarkable given that we're currently in an El Niño-neutral period.
There's a spread of more than 3°C between the coldest and hottest monthly temperatures, in line with the seasonal cycle. Since the land/sea ratio is larger on the Northern Hemisphere and land heats up faster than oceans, July typically is the hottest month of the year, so the annual mean temperature for the year 2019 will be somewhat lower than the temperature for July 2019.
Above image takes another perspective, showing NASA Land and Ocean Temperature Index (LOTI) data that are adjusted 0.78° to reflect a 1750 baseline (as opposed to NASA's default 1951-1980 baseline), to reflect ocean air temperatures (as opposed to sea surface temperatures) and higher polar anomaly (to better reflect absent data).
Two trends are added, based on the adjusted data, as described in an earlier analysis. The blue long-term trend is based on 1880-July 2019 data and points at a 3°C (or 5.4°F) rise by 2026. The red short-term trend is based on 2012-July 2019 data, to better illustrate El Niño/La Niña variability and the danger that large methane eruptions from the seafloor of the Arctic Ocean could result in near-term human extinction.
NASA's LOTI anomaly of 0.93°C above 1951-1980 for July 2019 becomes 1.71°C above pre-industrial when adjusted as described above. The trends also show that it could be 1.85°C above pre-industrial, in line with the earlier analysis that already pointed at a potential mean temperature for 2019 of 15.27°C, or 1.85°C above pre-industrial. Depending on what will happen in the Arctic and on further variables such as the strength of El Niño over the remainder of the year, 2019 could even cross the 2°C guardrail that politicians at the Paris Agreement pledged would not be crossed.
Above image shows the worrying rise of Northern Hemisphere sea surface temperature anomalies from the 20th century average, with the added trend illustrating the danger that this rise will lead to Arctic sea ice collapse and large methane eruptions from the seafloor of the Arctic Ocean, further accelerating the temperature rise.
Unbearable heat
As temperatures keep rising, there are places on the northern hemisphere where the July heat is becoming ever harder to bear.
The image on the right shows that on July 29, 2019, it felt like it was as hot as 57.2°C or 135°F in China (in the area marked by the green circle).
How could it get this hot? As the image underneath on the right shows, the temperature in that area was 35.1°C or 95.1°F (at the right circle), while it was much hotter at some places elsewhere in China, e.g. it was 41.5°C or 106.6°F at the left circle on July 29, 2019.
What made the weather so hard to bear was a combination of high temperature and high relative humidity, which was 81% in the area at the circle on the right at the time.
The jet stream is becoming ever more deformed as the Arctic heats up faster than the rest of the world. On July 29, 2019, the jet stream was all over the place, with a strong presence north of the circle, which made warm, moist air from the south move over China.
Since the Arctic continues to heat up faster than the rest of the world, such situations are likely to become more common. As noted in an earlier post, cyclones can increase humidity, making conditions worse. New research has meanwhile emerged pointing at the increasing risk associated with the combination of cyclones and heatwaves.
Wet Bulb Temperature
The temperature in that area of 35.1°C, at 81% relative humidity and a pressure level of 1004 hPa, translates into a wet bulb temperature of 32.11°C.
Had the temperature remained at 35.1°C, but had relative humidity kept rising to 100%, i.e. rainfall, the wet bulb temperature threshold of 35°C would have been exceeded (35.01°C). Alternatively, had relative humidity remained at 81%, but had the temperature kept rising to 38.2°C, the wet bulb temperature threshold of 35°C would equally have been exceeded (35.07°C), showing how dangerous the situation is. A wet bulb temperature of 35°C can be lethal, as the human body will be unable to lose heat, even when the wind is strong and no matter how much one drinks or sweats.
The situation is dire and calls for comprehensive and effective action, as described in the Climate Plan.
Record low Arctic sea ice extent for the time of year
Arctic sea ice minimum extent typically occurs about half September. In 2012, minimum extent was reached on September 17, 2012, when extent was 3.387 million km².
On July 28, 2019, Arctic sea ice extent was 6.576 million km². How much extent do you think there will be by September 17, 2019? From July 28, 2019, to September 17, 2019, that's a period of 52 days during which a lot of melting can occur. Could there be a Blue Ocean Event in 2019, with virtually all sea ice disappearing in the Arctic?
Consider this. Extent was 6.926 million km² on September 17, 1989. Extent was 3.387 million km² on September 17, 2012, so 3.539 million km² had disappeared in 23 years. Over those years, more ice extent disappeared than what was left on September 17, 2012.
The question is how much sea ice extent will be left when it will reach its minimum this year, i.e. in September 2019. The red dashed line on the image at the top continues the path of the recent fall in sea ice extent, pointing at zero Arctic sea ice extent in September 2019. Progress is followed at this post.
Zero Arctic sea ice in 2019
Zero Arctic sea ice in 2019 sounds alarming, and there is good reason to be alarmed.
Above map shows temperatures on Greenland on July 31, 2019, with temperatures at one location as high as 23.2°C or 73.8°F and at another location - in the north - as high as 14.2°C or 57.6°F.
The map on the right shows sea surface temperature anomalies compared to 1961-1990 as on July 29, 2019. Note the high anomalies in the areas where the sea ice did disappear during the past few months. The reason for these high anomalies is that the buffer has disappeared that previously had kept consuming heat in the process of melting.
Where that buffer is gone, the heat has to go somewhere else, so it will be absorbed by the water and it will also speed up heating of the atmosphere over the Arctic.
Sea ice melting is accelerating for a number of reasons:
Ocean Heat - Much of the melting of the sea ice occurs from below and is caused by heat arriving in the Arctic Ocean from the Atlantic Ocean and the Pacific Ocean.
Direct Sunlight - Hot air will melt the ice from above and this kind of melting can increase strongly due to changing wind patterns.
Rivers - Heatwaves over land can extend over the Arctic Ocean and they also heat up river water flowing into the Arctic Ocean.
Fires - Changing wind patterns can also increase the intensity and duration of such heatwaves that can also come with fires resulting in huge amounts of greenhouse gas emissions, thus further speeding up the temperature rise, and also resulting in huge emissions of soot that, when settling on sea ice, speeds up melting (see images below).
Numerous feedbacks will further speed up melting. Heating is changing the texture of the sea ice at the top and is making melt pools appear, both of which cause darkening of the surface. Some further feedbacks, i.e. storms and clouds are discussed below in more detail.
Above combination image shows smoke from fires in Siberia getting pushed over the Laptev Sea on August 11, 2019, due to cyclonic winds over the Arctic Ocean. This was also discussed in an earlier post. The image below shows the situation on August 12, 2019.
The image below shows the situation on August 14, 2019.
In the video below, Paul Beckwith discusses the heating impact of albedo loss due to Arctic sea ice loss, including the calculations in a recent paper.
As the Arctic is heating up faster than the rest of the world, it is also more strongly affected by the resulting extreme weather events, such as heatwaves, fires, strong winds, rain and hail storms, and such events can strongly speed up the melting of the sea ice.
All around Greenland, sea ice has now virtually disappeared. This is the more alarming considering that the thickest sea ice was once located north of Greenland. This indicates that the buffer is almost gone.
Why is disappearance of Arctic sea ice so important? Hand in hand with albedo loss as the sea ice disappears, there is loss of the buffer (feedbacks #1, #14 and more). 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.
Once the sea ice is gone, further heat must go elsewhere. This heat will raise the temperature of the water and will also make the atmosphere heat up faster.
Storms and Clouds
Storms: As temperatures in the Arctic are rising faster than at the Equator, the Jet Stream is changing, making it easier for warm air to enter the Arctic and for cold air to descend over continents that can thus become much colder than the oceans, and this stronger temperature difference fuels storms.
Clouds: More evaporation will occur as the sea ice disappears, thus further heating up the atmosphere (technically know as latent heat of vaporization).
In the video below, Paul Beckwith further discusses Arctic albedo change and clouds.
Disappearance of the sea ice causes more clouds to form over the Arctic. This on the one hand makes that more sunlight gets reflected back into space. On the other hand, this also make that less outward infrared radiation can escape into space. The net effect of more clouds is that they are likely cause further heating of the air over the Arctic Ocean (feedbacks #23 and #25).
More low-altitude clouds will reflect more sunlight back into space, and this occurs most during Summer when there is most sunshine over the Arctic. The image below, a forecast for August 17, 2019, shows rain over the Arctic. Indeed, more clouds in Summer can also mean rain, which can devastate sea ice, as discussed in an earlier post.
Regarding less outward radiation, the IPCC has long warned, e.g. in TAR, about a reduction in outgoing longwave radiation (OLR): "An increase in water vapour reduces the OLR only if it occurs at an altitude where the temperature is lower than the ground temperature, and the impact grows sharply as the temperature difference increases."
While reduction in OLR due to water vapor is occurring all year long, the impact is particularly felt in the Arctic in Winter when the air is much colder than the surface. In other words, less OLR makes Arctic sea ice thinner, especially in Winter.
The inflow of ocean heat into the Arctic Ocean can increase strongly as winds increase in intensity. Storms can push huge amounts of hot, salty water into the Arctic Ocean, as discussed earlier, such as in this post and this post. As also described at the extreme weather page, stronger storms in Winter will push more ocean heat from the Atlantic toward the Arctic Ocean, further contributing to Arctic sea ice thinning in Winter.
Seafloor Methane
As the buffer disappears that until now has consumed huge amounts of heat, the temperature of the water of the Arctic Ocean will rise even more rapidly, with the danger that further heat will reach methane hydrates at the seafloor of the Arctic Ocean, causing them to get destabilized and release huge amounts of methane (feedback #16).
Ominously, high methane levels were recorded at Barrow, Alaska, at the end of July 2019, as above image shows.
And ominously, a mean global methane level as high as 1902 ppb was recorded by the MetOp-1 satellite in the afternoon of July 31, 2019, as above image shows.
As the image on the right shows, mean global levels of methane (CH₄) have risen much faster than carbon dioxide (CO₂) and nitrous oxide (N₂O), in 2017 reaching, respectively, 257%, 146% and 122% their 1750 levels.
Temperature Rise
Huge releases of seafloor methane alone could make marine stratus clouds disappear, as described in an earlier post, and this clouds feedback could cause a further 8°C global temperature rise.
Indeed, a rapid temperature rise of as much as 18°C could result by the year 2026 due to a combination of elements, including albedo changes, loss of sulfate cooling, and methane released from destabilizing hydrates contained in sediments at the seafloor of oceans.
• Contribution of sea ice albedo and insulation effects to Arctic amplification in the EC-Earth Pliocene simulation, by Jianqiu Zheng et al. (2019) https://www.clim-past.net/15/291/2019
Smoke covers much of Siberia, as shown by the NASA Worldview image dated July 25, 2019.
The enormous intensity of the fires is illustrated by the image below, showing carbon monoxide (CO) levels as high as 80,665 ppb on July 25, 2019.
The image below shows that, at that same spot on July 25, 2019, carbon dioxide (CO₂) levels were as high as 1205 ppm.
The image below shows that aerosols from biomass burning were at the top end of the scale.
When soot from fires settles on snow and ice, it darkens the surface, resulting in more sunlight getting absorbed (instead of reflected back into space, as was previously the case), thus further speeding up the melting.
The loss of sea ice north of Greenland is particularly worrying, since this is the area where once the thickest sea ice was present. The image below shows the situation on July 24, 2019.
The image below shows the sea ice disappearing north of Greenland and Ellesmere Island on July 25, 2019.
The huge recent fall in sea ice volume is illustrated by the graph below, by Wipneus.
The naval.mil animation below illustrates the rapid fall in sea ice thickness, showing 30-day period including seven forecasts up to August 1, 2019.
The combination image below shows sea ice thickness forecasts for July 25, 2019, and for August 1, 2019.
Such a trend can further smooth out seasonal differences and El Niño/La Niña variability.
