Heatwaves and the danger of the Arctic Ocean heating up

 Heatwaves and Jet Stream Changes

Heatwaves are increasingly hitting higher latitudes, as illustrated by the forecasts below. The background behind this is that the temperature rise caused by people's emissions is also causing changes to the jet streams. 

[ click on images to enlarge ]

These changes to the Jet Stream are increasingly creating conditions for heatwaves to strike at very high latitudes, as also illustrated by the images on the right.

The first image on the right shows that surface temperatures as high as 48°C or 118.3°F are forecast in the State of Washington for June 30, 2021, at 01:00 UTC, at a latitude of 46.25°N. At the same time, even higher temperatures are forecast nearby at 1000 hPa level (temperatures as high as 119.4°C or 48.6°C). 

The next two images on the right show what happened to the jet stream. One image shows instantaneous wind power density at 250 hPa, i.e. at an altitude where the jet stream circumnavigates the globe, on June 26, 2021 at 11:00 UTC. The image features two green circles. The top green circle marks a location where the jet stream is quite forceful and reaches a speed of 273 km/h or 170 mph. The bottom green circle marks the same location where the 48°C is forecast on June 30, 2021. This shows how heat has been able to move north from as early as June 26, 2021.

The next image on the right shows the situation on June 30, 2021, 04:00 UTC, illustrating how such a jet stream pattern can remain in place (blocked) for several days (in this case for more than five days). The green circle again marks the same location where the 48°C is forecast (in the top image on the right).

This illustrates how a more wavy jet stream can enable high temperatures to rise to higher latitudes, while holding a pattern in place for several days, thus pushing up temperatures over time in the area.  

As said, these changes in the jet stream that are enabling hot air to rise up to high latitudes are caused by global warming. Accelerating warming in the Arctic is causing the temperature difference between the North Pole and the Equator to narrow, which in turn is making the jet stream more wavy.

The next image on the right shows that a UV index reading as high as 12 (extreme) is forecast for a location at 51.56°N in Washington for June 28, 2021, illustrating that such an extreme level of UV can occur at high latitudes, due to changes in the jet stream.

Accelerated Warming in the Arctic

As the temperature rise is accelerating due to people's emissions, it is speeding up more in the Arctic than anywhere else on Earth. 

The Arctic is heating up faster than elsewhere, as numerous feedbacks and tipping points are hitting the Arctic, including:

• Albedo loss goes hand in hand with decline of the snow and ice cover. Albedo is a measure of reflectivity of the surface. Albedo is higher as more sunlight is reflected back upward and less energy is getting absorbed at the surface. Albedo decline can occur as snow and ice disappears and the underlying darker soil and rock becomes exposed. Even when the snow and ice cover remains extensive, its reflectivity can decline, due to cracks and holes in the ice, due to formation of melt ponds on top of the ice and due to changes in texture (melting snow and ice reflects less light). Calving of the ice can take place where warmer water can reach it, and such calving can increase as storms strengthen and waves get larger.

• Furthermore, albedo loss can occur as dust, soot and organic compounds that are caused by human activities get deposited on the snow and ice cover, reducing the reflectivity of the surface. Organic compounds and nutrients in meltwater pools can lead to rapid growth of algae, especially at times of high insolation.

• Latent heat loss. As sea ice gets thinner, ever less ocean heat gets consumed in the process of melting the subsurface ice, to the point where - as long as air temperatures are still low enough - there still is a thin layer of ice at the surface that will still consume some heat below the surface, but that at the same time acts as a seal, preventing heat from the Arctic Ocean to enter the atmosphere.

• Wind changes including changes to the Jet Stream can further amplify the temperature rise in the Arctic. As the temperature difference between the North Pole and the Equator narrows, the Jet Stream becomes more wavy, spreading out widely at times. The changes to the jet stream cause more extreme weather, including heatwaves, forest fires, storms, flooding, etc. This can cause more aerosols to get deposited on the snow and ice cover. Stronger wind and storms over the North Atlantic can also speed up the flow of warm water into the Arctic Ocean.

Albedo loss, latent heat loss and changes to wind patterns can dramatically amplify the temperature rise in the Arctic. The temperature of the Arctic Ocean is rising accordingly, while there are a number of developments and events that specifically speed up the temperature rise of the water of the Arctic Ocean, as discussed below.

Arctic Ocean heating up

The temperature of the water of the Arctic Ocean is rising, due to a number of events and developments:

                 [ from the insolation page ]

• Solstice occurred on June 21, 2021. The Arctic is now receiving huge amounts of sunlight (see image on the right, from the insolation page).


• Sea surface temperatures and temperatures on land are very high in Siberia, Canada and Alaska. Strong winds can spread warm air over the Arctic Ocean.


• Arctic sea ice extent is low for the time of year, but at this stage, there still is a lot of sea ice present (compared to September). The sea ice acts as a seal, preventing ocean heat from entering the atmosphere, resulting in more heat remaining in the Arctic Ocean.
  
  

[ Lena River, Siberia ]

• Warm water from rivers is flowing into the Arctic Ocean, carrying further heat into the Arctic Ocean. Above image shows that on June 23, 2021, sea surface temperatures were 22.3°C or 72.2°F at a spot where water from the Lena River flows into the Arctic Ocean. The image on the right shows that at a nearby location the sea surface temperature was 20°C or 36°F higher than 1981-2011. 
  
  
• Warm water from the North Atlantic Ocean and the North Pacific Ocean is flowing into the Arctic Ocean and the amount of ocean heat flowing into the Arctic Ocean is rising each year.
  
  
• As mentioned above, latent heat loss is contributing to the rapid temperature rise in the Arctic. The remaining sea ice acts as a buffer, consuming ocean heat from below. Sea ice is getting thinner each year, so ever less ocean heat can get consumed in the process of melting the sea ice from below.


• Changes to the jet stream can also cause strong storms to dramatically speed up the amount of heat flowing into the Arctic Ocean, as discussed at the Cold freshwater lid on North Atlantic page.

The danger of the temperature rise of the Arctic Ocean

The danger of the temperature rise of the Arctic Ocean is that it can cause destabilization of hydrates at its seafloor, resulting in eruption of huge amounts of methane from hydrates and from free gas underneath the hydrates.

[ The Buffer has gone, feedback #14 on the Feedbacks page ]

In conclusion, changes to the jet stream could cause a huge temperature rise soon, while a 3°C rise could cause humans to go extinct, which is a daunting prospect. Even so, the right thing to do is to help avoid the worst things from happening, through comprehensive and effective action as described in the Climate Plan.

Links

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

• Insolation

https://arctic-news.blogspot.com/p/insolation.html

• Cold freshwater lid on North Atlantic

https://arctic-news.blogspot.com/p/cold-freshwater-lid-on-north-atlantic.html

• Most Important Message Ever
https://arctic-news.blogspot.com/2019/07/most-important-message-ever.html

• Could temperatures keep rising?

https://arctic-news.blogspot.com/2021/06/could-temperatures-keep-rising.html

• Latent Heat

https://arctic-news.blogspot.com/p/latent-heat.html

Snowstorms, the breach of the Arctic vortex and the effects of ice meltwater on the oceans

by Andrew Glikson

Warnings by leading climate scientists regarding the high sensitivity of the atmosphere in response to abrupt compositional changes, such as near-doubling of greenhouse gas concentrations, are now manifest: According to Wallace Broecker, (the “father” of climate science) “The paleoclimate record shouts out to us that, far from being self-stabilizing, the Earth's climate system is an ornery beast which overreacts to even small nudges, and humans have already given the climate a substantial nudge”. As stated by James Zachos, “The Paleocene hot spell should serve as a reminder of the unpredictable nature of climate”.

As snowstorms such as the “Beast from the East” (2018) and “Storm Darcy” (2021) sweep the northern continents, reaching Britain and as far south as Texas and Greece, those who still question the reality and consequences of global climate change, including in governments, may rejoice as if they have a new argument to question global warming.

However, as indicated by the science, these fronts result from a weakened circum-Arctic jet stream boundary due to decreased temperature polarity between the Arctic Circle and high latitude zones in Europe, Russia and North America. The reduced contrast allows migration of masses of cold Arctic air southward and of tropical air northward across the weakened jet stream boundary, indicating a fundamental shift in the global climate pattern (Figure 1).

Figure 1. (A) Extensions from the Arctic polar zone into Europe and North America; (B) Extension into North America; (C) weakening and increasing undulation of the Arctic jet stream boundary (NOAA) allowing intrusion of air masses of contrasted temperature across the boundary.

The weakening of the Arctic boundary is a part of the overall shift of climate zones toward the poles in both hemispheres, documented in detail in Europe (Figure 2). Transient cooling pauses are projected as a result of the flow of cold ice meltwater from Greenland and Antarctica into the oceans, leading to stadial cooling intervals.

Figure 2. Migration of climate zones in Europe during 1981-2010 and under +2°C. Faint pink areas represent advanced warming. (A, left) Agro‐climate zonation of Europe based on growing season length (GSL) and active temperature sum (ATS) obtained as an ensemble median from five different climate model simulations during the baseline period (1981–2010). (B, right) Ensemble median spatial patterns of agro-climate zones migration under 2°C global surface warming according to model RCP8.5. Gray areas represent regions where no change with respect to the baseline period is simulated.

A combination of ice sheet melting and the flow of melt water into the oceans on the one hand, and ongoing warming of tropical continental zones on the other hand, are likely to lead to the following:

• Storminess due to collisions of cold and warm air masses;
• As the ice sheets continue to melt, the cold meltwater enhances lower temperatures at shallow ocean levels, as modelled by Hansen et al. (2016) and Bonselaer et al (2018) (Figure 3A), as contrasted with warming at deeper ocean levels over large parts of the oceans. This transiently counterbalances the effects of global warming over the continents arising from the greenhouse effect; 
• The above processes herald chaotic climate effects, in particular along continental margins and island chains.

Figure 3. A. 2080–2100 meltwater-induced sea-air temperature anomalies relative to the standard RCP8.5 ensemble (Bronselaer et al., 2018), indicating marked cooling of parts of the southern oceans. Hatching indicates where the anomalies are not significant at the 95% level; B. Negative temperature anomalies through the 21st-22nd centuries signifying stadial cooling intervals (Hansen et al., 2016); C. A model of Global warming for 2096, where cold ice melt water occupies large parts of the North Atlantic and circum-Antarctica, raises sea level by about 5 meters and decreases global temperature by -0.33°C (Hansen et al., 2016).

The extreme rate at which the global warming and the shift of climate zones are taking place virtually within a period less than one generation-long, faster than major past warming events such as at the Paleocene-Eocene boundary 56 million years ago, renders the term “climate change” hardly appropriate, since what we are looking at is a sudden and abrupt event. 

According to Giger (2021) “Tipping points could fundamentally disrupt the planet and produce abrupt change in the climate. A mass methane release could put us on an irreversible path to full land-ice melt, causing sea levels to rise by up to 30 meters. We must take immediate action to reduce global warming and build resilience with these tipping points in mind.”

Computer modelling does not always capture the sensitivity, complexity and feedbacks of the atmosphere-ocean-land system as observed from paleoclimate studies. Many models portray gradual or linear responses of the atmosphere to compositional variations, overlooking self-amplifying effects and transient reversals associated with melting of the ice sheets and cooling of the oceans by the flow of ice melt.

According to Bonselaer et al. (2018) “The climate metrics that we consider lead to substantially different future climate projections when accounting for the effects of meltwater from the Antarctic Ice Sheet. These differences have consequences for climate policy and should be taken into account in future IPCC reports, given recent observational evidence of increasing mass loss from Antarctica” and “However, the effect on climate is not included (by the IPCC) and will not be in the upcoming CMIP6 experimental design. Similarly, the effects of meltwater from the Greenland Ice Sheet have so far not been considered, and could lead to further changes in simulated future climate”. Depending on future warming the effect of Antarctic ice meltwater may extend further, possibly becoming global.

By contrast to ocean cooling, further to NASA’s reported mean land-ocean temperature rise of +1.18°C in March 2020 above pre-industrial temperatures, relative to the 1951-1980 baseline, large parts of the continents, including central Asia, west Africa eastern South America and Australia are warming toward mean temperatures of +2°C and higher. The contrast between cooling of extensive ocean regions and warming of the continental tropics is likely to lead to extreme storminess, in particular along continent-ocean interfaces.

The late 20th century to early 21st century global greenhouse gas levels and regional warming rates have reached a large factor to an order of magnitude faster than warming events of past geological and mass extinction events, with major implications for the nature and speed of extreme weather events.

For these reasons the term “climate change” for the current extreme warming, which is reaching +1.5°C over the continents and more than +3°C over the Arctic over a period shorter than one century, no longer applies.

The world is looking at an extremely rapid shift in the climatic conditions that have allowed civilization to emerge.

Andrew Glikson

A/Prof. Andrew Glikson
Earth and Paleo-climate scientist
The University of New South Wales,
Kensington NSW 2052 Australia

Books:

The Asteroid Impact Connection of Planetary Evolution

http://www.springer.com/gp/book/9789400763272

The Archaean: Geological and Geochemical Windows into the Early Earth

http://www.springer.com/gp/book/9783319079073

Climate, Fire and Human Evolution: The Deep Time Dimensions of the Anthropocene

http://www.springer.com/gp/book/9783319225111

The Plutocene: Blueprints for a Post-Anthropocene Greenhouse Earth

http://www.springer.com/gp/book/9783319572369

Evolution of the Atmosphere, Fire and the Anthropocene Climate Event Horizon

http://www.springer.com/gp/book/9789400773318

From Stars to Brains: Milestones in the Planetary Evolution of Life and Intelligence

https://www.springer.com/us/book/9783030106027

Asteroids Impacts, Crustal Evolution and Related Mineral Systems with Special Reference to Australia

http://www.springer.com/us/book/9783319745442

More Extreme Weather

As temperatures rise, the weather is getting more extreme. Around the globe, extreme weather events are striking with ever greater frequency and intensity. 

In 2020, in the U.S. alone, a record number of 22 climate and weather disasters took place that each caused damage of more than 1 billion dollar, while jointly causing the deaths of 262 people. 

Rising temperatures cause stronger storms, droughts, heatwaves and forest fires. Rising temperatures are also behind the cold weather that is currently hitting large parts of North America. Two mechanisms that, by distorting the Jet Stream, are contributing to more extreme weather are described below. 

Distortion of the Jet Streams - two mechanisms

The Jet Streams used to circumnavigate the globe in narrow bands. World climate zones used to be kept well apart by stable Jet Streams. 

On the Northern Hemisphere, the coldest point used to be the North Pole, so wind used to flow from the tropics to the North Pole, while the wind was moved to the side due to Earth's turning. 

Polar Jet Stream and Subtropical Jet Stream - NOAA image

This resulted in two Jet Streams forming, circum-navigating the globe in relatively narrow and straight bands, i.e. the Polar Jet Stream at 60°N and the Subtropical Jet Stream at about 30°N. 

 

Polar Jet Stream (blue) and Subtropical
Jet Stream (red) - NOAA image

First mechanism distorting the Jet Stream

The first mechanism distorting the Jet Stream is that, as the Arctic gets hit much harder by temperature rises, the difference in temperature decreases between the North Pole and the Equator.

This slows down the speed at which wind travels from the Tropics to the North Pole, in turn making the Jet Stream more wavy, just like a slow-moving river over flat land will take a winding route and meander.

For years, Jennifer Francis et al. warned that this will cause more extreme weather in mid latitudes. Arctic-News described Deformation of the Jet Stream as Opening the Doorways to Doom, i.e. one of the feedbacks (#10) of accelerated Arctic warming.

Second mechanism distorting the Jet Stream

Due to the rapid temperature rise of the Arctic Ocean, the North Pole is increasingly not the coldest place on the Northern Hemisphere.

Instead, the air over Greenland, North Canada and Siberia is increasingly more cold than before, and can be much colder than the North Pole, as illustrated by the ClimateReanalyzer image on the right.

This creates temperature and pressure conditions over the East Pacific and over North America that make the Jet Stream branch out.

On the next image on the right, the Jet Stream can be seen running over the West Pacific at speeds as high as 387 km/h or 241 mph (green circle) and moving within a narrow and straight band.

The Jet Stream is then confronted with much different conditions over North America that make the Jet Stream branch out widely (white arrows), with one branch moving north and going circular over the Arctic Ocean, while at the other end a branch can be seen dipping below the Equator.

As a result of these two distortion mechanisms, cold air that used to stay contained over the North Pole, can descend more easily over Siberia and North America, causing more extreme weather, while also taking away opportunities for the sea ice to build up to the strength and depth than it used to have. 

The combination image below shows forecasts for February 6, 2021.

On the above combination image, the left panel shows that, not far apart from each other and at the same time, temperature anomalies over North America are forecast to approach the top end and the bottom end of the scale. The right panel shows that temperatures over North America and Siberia are forecast to be much lower than over the Arctic Ocean.

As the temperature difference between land and ocean gets stronger on the Northern Hemisphere in Winter, the transfer of water vapor and heat to the atmosphere increases (#25 on the feedbacks page, image right). Storms and clouds forming over the North Atlantic trap heat and move much heat toward the North Pole.

 
Formation of clouds can be further facilitated by aerosols (feedback #9). A recent study looks at how melting sea ice can cause more release of iodine into the atmosphere, seeding the growth of new clouds that trap longwave radiation that would otherwise go into space.

The combination image below shows in the left panel how a branch of the Jet Stream is forecast to be moving over the North Pole at speeds as high as 107 km/h or 67 mph on February 16, 2021. Hours later that day, as the globe in the right panel shows, the surface temperature on the North Pole is forecast to be -18°C, i.e. warmer than the white-blue color (about -20°C) that covers most of North America.

As the globe in the left panel of the combination image below shows, temperature anomalies in Texas were approaching the bottom end of the scale on February 15, 2021, i.e. -32°C or -57.6°F (below 1979-2000), while the globe in the right panel shows that on February 16, 2021, temperature anomalies in between Greenland and the North Pole were forecast to approach the top end of the scale, i.e. 32°C or 57.6°F (above 1979-2000). 

Above freezing at North Pole?

As the combination image below shows, the temperature at the North Pole is forecast to be 0°C or 32°F, panel right, on February 22, 2021, 18:00 UTC, while temperature anomalies at the North Pole are forecast to be at the top end of the scale, i.e. 32°C or 57.6°F above 1979-2000. 

The light-blue color over the North Atlantic on the globe on the left is a cold anomaly resulting from cold air moving from North America over the Atlantic Ocean (forecast initiated Feb.15, 2021, 18:00 UTC).

Ominously, sea ice is breaking up north of Greenland. 

And ominously, the N20 satellite recorded methane levels as high as 2835 ppb at 399.1 mb on the afternoon of February 17, 2021.

Conclusion

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


Links

• 2020: Hottest Year On Record
https://arctic-news.blogspot.com/2021/01/2020-hottest-year-on-record.html

• NOAA - U.S. Billion-Dollar Weather and Climate Disasters: Overview
https://www.ncdc.noaa.gov/billions/overview

• Climate Reanalyzer
https://climatereanalyzer.org

• Nullschool

https://earth.nullschool.net

• Feedbacks in the Arctic

https://arctic-news.blogspot.com/p/feedbacks.html

• Polar jet stream appears hugely deformed
https://arctic-news.blogspot.com/2012/12/polar-jet-stream-appears-hugely-deformed.html

• Evidence linking Arctic amplification to extreme weather in mid‐latitudes - by Jennifer Francis et al. 

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012GL051000

• Opening the Doorways to Doom (feedback #14)

https://arctic-news.blogspot.com/2012/08/opening-the-doorways-to-doom.html

• Role of iodine oxoacids in atmospheric aerosol nucleation - by Xu-Cheng He et al. 

https://science.sciencemag.org/content/371/6529/589

• Cloud-Making Aerosol Could Devastate Polar Sea Ice

https://www.quantamagazine.org/cloud-making-aerosol-could-devastate-polar-sea-ice-20210223

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

Why stronger winds over the North Atlantic are so dangerous

The image below shows high temperatures over Antarctica. News reports show that temperatures as high as 18.3°C or 65°F were recently recorded on Antarctica. The image also shows high temperatures for the time of year over the North Atlantic, with strong winds along the path of the Gulf Stream.

Wind and temperature on February 8, 2020 at 18:00 UTC, near sea level (~100m, at 1000hPa)

The image below shows that wind speeds as high as 430 km/h or 267 miles per hour (mph) were recorded (at 250 hPa, jet stream, at green circle).

Wind on February 8, 2020 at 18:00 UTC, at 250 hPa (jet stream)

Above image also shows that Instantaneous Wind Power Density at the time was as high as 330.1 kW/m² (at the green circle). This is almost as strong as the wind was in 2015. Then, the Jet Stream at a nearby location reached a similar speed while Instantaneous Wind Power Density was slightly higher, at 338.3 kW/m².

So, why are stronger winds over the North Atlantic so dangerous?

Emissions by people heat up the air, which heats up oceans and makes winds stronger, in turn speeding up global ocean currents.

A recent study found increased kinetic energy in about 76% of the upper 2,000 meters of global oceans, as a result of intensification of surface winds since the 1990s.

As oceans heat up, more water evaporates from the sea surface. This evaporation will cool the sea surface somewhat, thus making that the sea surface can be colder than the water underneath the sea surface. Some of the water vapor will return to the ocean in the form of precipitation, but for each degree Celsius of warming, the atmosphere will hold 7% more water vapor, so much of the water vapor will remain in the atmosphere.

More water vapor in the atmosphere will further speed up global heating, since water vapor is a potent greenhouse gas.

Much of the water vapor will also get blown further along the path of the Gulf Stream in the direction toward the Arctic before precipitating, thus contributing - along with meltwater - to the formation of a cold freshwater lid at the surface of the ocean.

Stronger winds along the path of the Gulf Stream can make huge amounts of warm, salty water travel underneath this cold freshwater lid toward the Arctic, pushing up temperatures and salinity levels at the bottom of the Arctic Ocean and threatening to destabilize methane hydrates that are contained in sediments at the seafloor of the Arctic Ocean.

In summary, stronger winds can trigger huge eruptions of methane. Another recent study found that Arctic permafrost thaw plays a greater role in climate change than previously estimated. All this should be reason to take strong action to reduce this danger.

Emissions keep rising

Sadly, emissions show no sign of decline. The daily average CO₂ level at Mauna Loa, Hawaii was 416.08 ppm on February 10, 2020, higher than it has been for millions of years.

Since the annual peak is typically reached in May, even higher levels can be expected soon.

During the Paleocene–Eocene Thermal Maximum (PETM), about 55.5 million years ago, massive amounts of carbon dioxide were released into the atmosphere. The period lasted for some 200,000 years and global temperatures increased by 5–8°C. From the way emissions are rising now, it looks like we could reach even higher CO₂e forcing soon.

Indeed, the situation at Barrow, Alaska, doesn't look better, as illustrated by the image below, showing CO₂ levels up to February 13, 2020.

Very worrying is the rise in methane levels, as illustrated by the image below.

The image below shows methane levels at Barrow, Alaska, up to February 13, 2020.

High methane levels were recorded over the East Siberian Arctic Shelf (ESAS) by the MetOp-2 satellite on February 10 & 11, 2020, pm at 469 mb.

In the video below, recorded January 3, 2020, Guy McPherson and Josef Lauber discuss the track we're on.

Below is a video of an earlier discussion (February 25, 2019) between Guy McPherson and Josef Lauber.

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


Links

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

• News release: Global ocean circulation is accelerating from the surface to the abyss
https://www.eurekalert.org/pub_releases/2020-02/aaft-goc020320.php

• Deep-reaching acceleration of global mean ocean circulation over the past two decades - by Shijian Hu et al.
https://advances.sciencemag.org/content/6/6/eaax7727

• Arctic permafrost thaw plays greater role in climate change than previously estimated
https://www.colorado.edu/today/2020/02/03/arctic-permafrost-thaw-plays-greater-role-climate-change-previously-estimated

• The Arctic’s thawing ground is releasing a shocking amount of dangerous gases
https://www.nationalgeographic.com/science/2020/02/arctic-thawing-ground-releasing-shocking-amount-dangerous-gases

• Cold freshwater lid on North Atlantic 

https://arctic-news.blogspot.com/p/cold-freshwater-lid-on-north-atlantic.html

• Carbon release through abrupt permafrost thaw - by Merritt Turetsky et al.
https://www.nature.com/articles/s41561-019-0526-0

• NOAA Global CH4 Monthly Means
https://www.esrl.noaa.gov/gmd/ccgg/trends_ch4

July 2019 Hottest Month On Record

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.


Links

• Another exceptional month for global average temperatures, Copernicus Climate Change Service, ECMWF
https://climate.copernicus.eu/another-exceptional-month-global-average-temperatures

• July matched, and maybe broke, the record for the hottest month since analysis began
https://public.wmo.int/en/media/news/july-matched-and-maybe-broke-record-hottest-month-analysis-began

• NOAA Global Climate Report - July 2016
https://www.ncdc.noaa.gov/sotc/global/201607

• July 2019 Global Temperature Update, by James Hansen
http://www.columbia.edu/~mhs119/Temperature/Emails/July2019.pdf

• An emerging tropical cyclone–deadly heat compound hazard, by Tom Matthews et al. (2019)
https://www.nature.com/articles/s41558-019-0525-6

• Most Important Message Ever
https://arctic-news.blogspot.com/2019/07/most-important-message-ever.html

• Temperature
https://arctic-news.blogspot.com/p/temperature.html

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

• It could be unbearably hot in many places within a few years time
https://arctic-news.blogspot.com/2016/07/it-could-be-unbearably-hot-in-many-places-within-a-few-years-time.html

• Peaks Matter
https://arctic-news.blogspot.com/2018/08/peaks-matter.html

• Extinction Alert
https://arctic-news.blogspot.com/2019/02/extinction-alert.html

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

High Temperatures over the Arctic

Melt extent over Greenland was well over 40% on June 12, 2019.

The surface melt map that day (on the right) shows many coastal areas for which data are missing, as indicated by the grey color.

As the June 13, 2019, NASA Worldview satellite image (underneath, right) shows, snow and ice in many coastal areas has melted away.

Four nullschool images are added below. The first one shows air temperatures over Greenland as high as 22.7°C or 72.9°F on June 13, 2019, at 1000 mb. Also note the high temperatures visible over East Siberia and the East Siberian Arctic Shelf (ESAS).

A second nullschool image shows that a temperature of 0.9°C or 33.5°F was recorded at the North Pole on June 15, 2019. Temperatures above the melting point of ice have been recorded at the North Pole for some time now.

The third nullschool image shows that temperatures as high as 30.5°C or 86.8°F are forecast for June 19, 2019, near Tiksi, which is on the coast of Siberia where the Lena River flows into the Laptev Sea and the Arctic Ocean.

What causes this? As the Arctic is heating up faster than the rest of the world, the path of the jet stream is changing. On June 19, 2019, the jet stream is forecast to move from Siberia to the Laptev Sea at speeds as high as 192 km/h or 119 mph.

The satellite image shows smoke from fires getting pushed by strong winds over the Laptev Sea on June 16, 2019. Smoke settling on ice makes it darker, further speeding up the melting.

[ Temperatures over Greenland as high as 22.7°C or 72.9°F on June 13, 2019, at 1000 mb ]

[ Temperature of 0.9°C or 33.5°F at the North Pole on June 15, 2019 ]

[ temperatures as high as 30.5°C or 86.8°F are forecast for June 19, 2019, near Tiksi, Siberia ]

[ jet stream is forecast to move from Siberia to the Laptev Sea as fast as at 192 km/h or 119 mph June 19, 2019 ]

[ fires getting pushed by strong winds on June 16, 2019, over the Laptev Sea (at bottom of image)  ]

In conclusion, temperatures over the Arctic are high. Changes to the jet stream due to the rapid heating of the Arctic are causing hot air to move deep into the Arctic, including over the Laptev Sea all the way to the North Pole, while high temperatures in Siberia are warming up the water of rivers, causing warm water to flow into the Arctic Ocean.  

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