Showing posts with label change. Show all posts
Showing posts with label change. Show all posts

Wednesday, September 16, 2020

Temperatures threaten to become unbearable

Many people could face unbearable temperatures soon. 

Temperature anomalies on land in the Northern Hemisphere (red) are spread out much wider and they are more than 0.5°C higher than global land+ocean anomalies (blue).


The pale green and grey trends are both long-term trends based on January 1880-August 2020 NOAA data. The short-term red and blue trends, based on January 2013-August 2020 NOAA data, are added to show the potential for a rapid rise. How could temperatures possibly rise this fast? 

A rapid temperature rise could eventuate by 2026 due to a number of contributing factors:
• crossing of the latent heat and methane tipping points
• moving toward an El Niño 
• entering solar cycle 25
• changes in aerosols
• feedbacks kicking in more strongly as further tipping points get crossed.

Crossing the Latent Heat and Methane Hydrate Tipping Points

The image below, updated from an earlier post, shows two such tipping points.


The August 2020 ocean temperature anomaly on the Northern Hemisphere was 1.13°C above the 20th century average. The image shows a trend based on January 1880-August 2020 NOAA data. The latent heat tipping point is estimated to be 1°C above the 20th century average. Crossing the latent heat tipping point threatens to cause the methane hydrates tipping point to be crossed, estimated to be 1.35°C above the 20th century average.

Keep in mind that above images show temperature anomalies from the 20th century average, which is NOAA's default baseline. As an earlier analysis points out, when using a 1750 baseline and when using ocean air temperatures and higher Arctic anomalies, we may have already crossed both the 1.5°C and the 2°C thresholds that politicians at the Paris Agreement pledged would not get crossed.

Natural Variability - El Niño and Solar Cycle

Currently, we are currently in a La Niña period, which suppresses air temperatures.

Only a thin layer of sea ice remained left in the Arctic, with extent almost as low as it was in 2012 around this time of year, as discussed in the previous post. As air temperatures dropped in September 2020, Arctic sea ice extent started to increase again about September 15, 2020. This made that a patch of sea ice remained present at the surface of the Arctic Ocean, despite the dramatic thinning of the sea ice. 

When an El Niño event returns, conditions will get worse. 


How long will it take before we'll reach the peak of the upcoming El Niño? NOAA says
El Niño and La Niña episodes typically last nine to 12 months, but some prolonged events may last for years. While their frequency can be quite irregular, El Niño and La Niña events occur on average every two to seven years. Typically, El Niño occurs more frequently than La Niña.
The temperature rise is strongest in the Arctic, as illustrated by the zonal mean temperature anomaly map below. The map has latitude on the vertical axis and shows anomalies as high as 4.83°C or 8.69°F in the Arctic. The North Pole is at the top of the map, at 90° North, the Equator is in the middle, at 0°, and the South Pole is at the bottom, at -90° South. And yes, NASA's default baseline is 1951-1980, so anomalies are even higher when using a 1750 baseline. 


So, what could make the difference next year is an upcoming El Niño. Solar irradiance is also on the rise, in line with the 11-year Solar Cycle.


Above image shows a NOAA graph depicting the current Solar Cycle (24) and the upcoming Solar Cycle (25). 

In 2019, Tiar Dani et al. analyzed a number of studies and forecasts pointing at the maximum in the upcoming Solar Cycle occurring in the year 2023 or 2024.

The analysis found some variation in intensity between forecasts, adding images including the one on the right, which is based on linear regression and suggests that the Solar Cycle 25 may be higher than the previous Solar Cycle 24. 

In 2012, Patrick (Pádraig) Malone analyzed factors critical in forecasting when an ice-free day in the Arctic sea first might occur. 

Patrick concluded that once solar activity moved out of the solar minimum, Arctic sea ice extent would start to crash. Accordingly, a Blue Ocean Event could occur as early as 2021, as illustrated by the image below.  


Further Tipping Points and Feedbacks

Further tipping points and feedbacks can start kicking in more strongly as one tipping point gets crossed. At least ten tipping points apply to the Arctic, as discussed in an earlier post and it looks like the latent heat tipping point has already been crossed. 

Ocean heat is very high in the North Atlantic and the North Pacific, and heat continues to enter the Arctic Ocean. 


Arctic sea surface temperatures and air temperature are now high since ocean heat, previously consumed by sea ice, is now coming to the surface where the sea ice has disappeared.

As above image shows, sea surface temperature anomalies in the Arctic Ocean on September 14, 2020, were as high as 9.3°C or 16.8°F (at the location marked by green circle), compared to the daily average during the years 1981-2011. 

These high sea surface temperature anomalies occur at locations where the daily average during the years 1981-2011 was around freezing point at this time of year.

Part of this ocean heat is rising into the atmosphere over the Arctic Ocean, resulting in high air temperatures that in turn prevent formation of sea ice thick enough to survive until the next melting season. The image on the right shows a forecast of Arctic air temperatures (2 m) that are 5°C higher than 1979-2000 (forecast for October 5, 2020, 18Z run Sep 26, 2020 06Z). 

Methane Danger is High


Ominously, peak methane levels of 2762 parts per billion (ppb) were recorded by the MetOp-1 satellite on the morning of September 20, 2020, at 586 milibar (mb), as above image shows.


Mean methane levels of 1925 ppb were recorded by the MetOp-1 satellite on the morning of September 20, 2020, at 293 mb, as above image shows.


Peak methane levels of 2813 ppb were recorded by the MetOp-1 satellite on the afternoon of September 30, 2020, at 469 mb, as above image shows. 


Methane has been rising most at higher altitudes over the past few years. On September 26, 2020 pm, the MetOp-1 satellite recorded a mean global methane level of 1929 ppb at 293 mb, which is equivalent to a height of 9.32 km or 30,57 ft, i.e. in the lower stratosphere over the North Pole (the top of the troposphere over the Equator is higher, at about 17 km).

Why methane is so important

As illustrated by the image on the right, from an earlier post, high methane levels could be reached within decades, and such a scenario could unfold even without sudden big bursts, but merely due to a continuation of a trend based on data up to 2014. This would obviously result in a huge rise in global temperature. 

A huge rise in global temperature would eventuate even earlier in case of a big burst of methane erupting from the seafloor of the Arctic Ocean. 

Methane's initial global warming potential (GWP) is very high. For the first few years after its release, methane is more than 150 times as strong as a greenhouse gas compared to carbon dioxide, as discussed in an earlier post.

How high are current methane levels? NOAA's May 2020 level for methane was 1874.7 ppb

Using a GWP of 150, this translates into 1.8747 x 150 = 281.205 ppm CO₂e. 

NOAA's figures are conservative, given that NOAA measures methane at marine surface level. 

Anyway, when using this conservative NOAA methane figure of 1874.7 ppb which at a GWP of 150 results in 281.205 ppm CO₂e, and when using an additional 413.6 ppm for recent carbon dioxide levels (NOAA's global May 2020 CO₂ level), these two add up to 694.805 ppm CO₂e, which is 505.195 CO₂e away from the cloud feedback tipping point (1200 CO₂e) that can, on its own, raise global temperatures instantly by 8°C. 

This is illustrated by the image on the right, an update from an earlier post

An additional eruption of methane from the Arctic Ocean into the atmosphere of 505.195 CO₂e translates into 505.195 / 150 = 3.368 ppm or 3368 ppb of methane. 

If the current amount of methane in the atmosphere is about 5 Gt, then 3368 ppb of methane corresponds with an amount of methane just under 9 Gt.

Coincidently, a peak level of 3369 ppb was recorded on August 31, 2018, pm. Granted, there is a large difference between a local peak level and a global mean level, but then again, a much smaller burst of methane can trigger the clouds feedback.

Even a relatively small burst of methane could trigger the clouds feedback, given that it will cause huge heating of the Arctic both directly and indirectly, in turn triggering further eruptions of methane from the seafloor of the Arctic Ocean.

Huge direct heating of the Arctic could occur due to methane's high immediate GWP and its even higher Local Warming Potential (LWP) given that the release takes place in the Arctic, while huge indirect heating of Arctic would occur due to the resulting decline of sea ice and of much of the permafrost on land.

Even a relatively small burst of methane could cause not only albedo losses but also releases of carbon dioxide, methane and nitrous oxide and further fast feedbacks such as a rise in clouds and water vapor, especially over the Arctic Ocean, as illustrated by the image on the right, from the extinction page and an earlier post.

Importantly, the initial trigger to a huge temperature rise by 2026 could be an event that is typically categorized under natural variability, such as an El Niño, increased solar irradiance or a storm causing a sudden large influx of hot, salty water into the Arctic Ocean and causing an eruption of seafloor methane. Indeed, a seemingly small forcing can result in total collapse that takes place so rapidly that any political action will be too little, too late.

The video below illustrates the importance of the Precautionary Principle. The video shows how a seemingly small bump by a forklift causes all shelves in a warehouse to collapse. 


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


Links

• NOAA Global Climate Report - August 2020
https://www.ncdc.noaa.gov/sotc/global/202008

• Multivariate El Niño/Southern Oscillation (ENSO) Index Version 2 (MEI.v2)
https://psl.noaa.gov/enso/mei

• What are El Niño and La Niña?

• NOAA ISIS Solar Cycle Sunspot Number Progression

• Multiple regression analysis predicts Arctic sea ice - by Patrick Malone (Pádraig) Malone 
https://www.facebook.com/Amber.and.Patrick/posts/1140053003062976 

• Prediction of maximum amplitude of solar cycle 25 using machine learning - by Tiar Dani et al. 
https://iopscience.iop.org/article/10.1088/1742-6596/1231/1/012022

• NOAA - Trends in Artmospheric Methane 

• Trends in Atmospheric Carbon Dioxide - global

• When will we die?

• A rise of 18°C or 32.4°F by 2026?

• Most Important Message Ever

• Blue Ocean Event
https://arctic-news.blogspot.com/2018/09/blue-ocean-event.html

• Record Arctic Warming
https://arctic-news.blogspot.com/2016/04/record-arctic-warming.html

• Warning of mass extinction of species, including humans, within one decade



Tuesday, December 17, 2019

Extinction in 2020?


Above image depicts how humans could go extinct as early as 2020. The image was created with NASA LOTI 1880-Nov.2019 data, 0.78°C adjusted to reflect ocean air temperatures (as opposed to sea surface temperatures), to reflect higher polar temperature anomalies (as opposed to leaving out 'missing' data) and to reflect a 1750 baseline (as opposed to a 1951-1980 baseline), with two trends added. Blue: a long-term trend based on Jan.1880-Nov.2019 data. Red: a short-term trend, based on Jan.2009-Nov.2019 data, to illustrate El Niño/La Niña variability and how El Niño could be the catalyst to trigger huge methane releases from the Arctic Ocean.

How was above image created? Let's first look at the baseline. The NASA default baseline is 1951-1980. The added trend in the image below shows early 1900s data to be well below this 1951-1980 baseline. In this analysis, a 0.28°C adjustment was therefore used to reflect this, and to reflect a 1750 baseline, a further 0.3°C was used, adding up to a 0.58°C baseline adjustment.


Furthermore, the NASA Land+Ocean temperature index (LOTI) uses sea surface temperatures, but ocean air temperatures seem more appropriate, which adds a further 0.1°C adjustment. Also, when comparing current temperatures with preindustrial ones, it's hard to find data for the polar areas. Treating these data as 'missing' would leave important heating out of the picture. After all, the polar areas are heating up much faster than the rest of the world, and especially so in the Arctic region. Therefore, a further 0.1°C adjustment was used to reflect higher polar temperature anomalies, resulting in the above-mentioned 0.78°C adjustment.

Finally, the red trend illustrates El Niño/La Niña variability. As discussed in a recent post, an El Niño is forecast for 2020 and this could be the catalyst to trigger huge methane releases from the Arctic Ocean.

The image below shows El Niño/La Niña variability going back to 1950, added to the NOAA monthly temperature anomaly.



As said, the Arctic region is heating up much faster than the rest of the world. There are several reasons why this is the case. Decline of the sea ice makes that less sunlight gets reflected back into space and that more sunlight is reaching the Arctic Ocean. This also causes more water vapor and clouds to appear over the Arctic Ocean. Furthermore, Arctic sea ice has lost most of the thicker multi-year ice that used to extend meters below the surface, consuming huge amounts of ocean heat entering the Arctic Ocean along ocean currents from the North Atlantic and the North Pacific oceans.

[ created with NOAA Arctic Report Card 2019 image ]
Above-mentioned feedbacks (albedo changes and more water vapor and clouds) contribute to higher temperatures in the Arctic. Furthermore, as the temperature difference between the North Pole and the Equator narrows, the jet stream changes, which can lead to further Arctic heating, i.e. higher temperatures of the atmosphere over the Arctic Ocean and over land around the Arctic Ocean, which in turn causes higher temperatures of the water flowing into the Arctic Ocean from rivers.

Furthermore, jet stream changes can also cause additional heating of parts of the Pacific Ocean and the Atlantic Ocean.

[ click on images to enlarge ]
Above image shows that sea surface temperature anomalies off the East Coast of North America as high as 13.6°C or 24.4°F were recorded on December 18, 2019.

Ocean currents can bring huge amounts of heat into the Arctic Ocean, and this can be amplified due to cyclones speeding up the inflow of water from the Atlantic Ocean and the Pacific Ocean into the Arctic Ocean.


As above image shows, the temperature rise of the oceans on the Northern Hemisphere is accelerating. This constitutes a critical tipping point, i.e. there are indications that a rise of 1°C will result in most of the sea ice underneath the surface to disappear. This sea ice used to consume the inflow of warm, salty water from the Atlantic Ocean and the Pacific Ocean. So, while there may still be sea ice left at the surface, since low air temperatures will cause freezing of surface water, the latent heat buffer has gone.


As long as there is sea ice, this 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 danger is that, as Arctic Ocean heating accelerates further, hot water will reach sediments at the Arctic Ocean seafloor and trigger massive methane eruptions, resulting in a huge abrupt global temperature rise. As discussed in an earlier post, a 3°C will likely suffice to cause extinction of humans.


Earlier this year, an Extinction Alert was issued, followed by a Stronger Extinction Alert.

In a rapid heating scenario:
  1. a strong El Niño would contribute to
  2. early demise of the Arctic sea ice, i.e. latent heat tipping point +
  3. associated loss of sea ice albedo,
  4. destabilization of seafloor methane hydrates, causing eruption of vast amounts of methane that further speed up Arctic warming and cause
  5. terrestrial permafrost to melt as well, resulting in even more emissions,
  6. while the Jet Stream gets even more deformed, resulting in more extreme weather events
  7. causing forest fires, at first in Siberia and Canada and
  8. eventually also in the peat fields and tropical rain forests of the Amazon, in Africa and South-east Asia, resulting in
  9. rapid melting on the Himalayas, temporarily causing huge flooding,
  10. followed by drought, famine, heat waves and mass starvation, and
  11. collapse of the Greenland Ice Sheet.
[ from an earlier post ]

The precautionary principle calls for appropriate action when dangerous situations threaten to develop. How can we assess such danger? Risk is a combination of probability that something will eventuate and severity of the consequences. Regarding the risk, there is growing certainty that climate change is an existential threat, as discussed in a recent post. There's a third dimension, i.e. timescale. Imminence alone could make that a danger needs to be acted upon immediately, comprehensively and effectively. While questions may remain regarding probability, severity and timescale of the dangers associated with climate change, the precautionary principle should prevail and this should prompt for action, i.e. comprehensive and effective action to reduce damage is imperative and must be taken as soon as possible.

The image below gives a visual illustration of the danger.


Polynomial trendlines can point at imminent danger by showing that acceleration could eventuate in the near future, e.g. due to feedbacks. Polynomial trendlines can highlight such acceleration and thus warn about dangers that could otherwise be overlooked. This can make polynomial trendlines very valuable in climate change analysis. In the image below, the green linear trend and the blue polynomial trend are long-term trends (based on Jan.1880-Nov.2019 data), smoothing El Niño/La Niña variability, but the blue polynomial trend better highlights the recent temperature rise than the green linear trend does. The red short-term trend (based on Jan.2009-Nov.2019 data) has the highest R² (0.994) and highlights how El Niño could be the catalyst for huge methane eruptions from the Arctic Ocean, triggering a huge global temperature rise soon.


The image below, from an earlier post, explains the speed at which warming elements can strike, i.e. the rise could for a large part occur within years and in some cases within days and even immediately.


As the image below shows, peak methane levels as high as 2737 parts per billion (ppb) were recorded by the MetOp-2 satellite in the afternoon of December 20th, 2019, at 469 mb. Ominously, a large part of the atmosphere over the East Siberian Arctic Shelf (ESAS) is colored solid magenta, indicating methane levels above 1950 ppb.



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



Links

• NASA - GISS Surface Temperature Analysis (GISTEMP v4)
https://data.giss.nasa.gov/gistemp/maps/index_v4.html

• NOAA Northern Hemisphere ocean temperature anomalies through November 2019
https://www.ncdc.noaa.gov/cag/global/time-series/nhem/ocean/1/11/1880-2019

• NOAA - Monthly temperature anomalies versus El Niño
https://www.ncdc.noaa.gov/sotc/global/201911/supplemental/page-3

• 2020 El Nino could start 18°C temperature rise
https://arctic-news.blogspot.com/2019/11/2020-el-nino-could-start-18-degree-temperature-rise.html

• NOAA Arctic Report Card 2019
https://www.arctic.noaa.gov/Report-Card/Report-Card-2019

• Critical Tipping Point Crossed In July 2019
https://arctic-news.blogspot.com/2019/09/critical-tipping-point-crossed-in-july-2019.html

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

• Accelerating greenhouse gas levels
https://arctic-news.blogspot.com/2019/11/accelerating-greenhouse-gas-levels.html

• Debate and Controversy
https://arctic-news.blogspot.com/p/debate.html

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

• Stronger Extinction Alert
https://arctic-news.blogspot.com/2019/03/stronger-extinction-alert.html

• Abrupt Warming - How Much And How Fast?
http://arctic-news.blogspot.com/2017/05/abrupt-warming-how-much-and-how-fast.html

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



Wednesday, November 27, 2019

Accelerating greenhouse gas levels

The United Nations Environment Programme (UNEP) just released its annual Emissions Gap Report, warning that even if all current unconditional commitments under the Paris Agreement are implemented, temperatures are expected to rise by 3.2°C, bringing even wider-ranging and more destructive climate impacts.

The report adds that a continuation of current policies would lead to a global mean temperature rise of 3.5°C by 2100 (range of 3.4–3.9°C, 66% probability) and concludes that current policies will clearly not keep the temperature rise below 3°C and that temperatures may rise by much more than that.

Below is the UNEP video On the brink: Emissions Gap Report findings in 60 seconds.


[ image from earlier post ]
Indeed, the rise in greenhouse gas levels appears to be accelerating, despite pledges made under the Paris Agreement to holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels.

The World Meteorological Organization (WMO) recently reported carbon dioxide (CO₂) concentrations for 2018 of 407.8 ppm (parts per million), as illustrated by the image on the right. The WMO adds that CO₂ levels, as well as methane and nitrous oxide levels, had all surged by higher amounts than during the past decade.

In energy, fossil fuel consumption for heating and transport increased. While renewables grew strongly in 2018, an even larger part of the growth in electricity was generated by fossil fuel, particularly by coal and natural gas. 

As the image below shows, a trend based on NOAA March 1958 through October 2019 monthly mean CO₂ data at Mauna Loa points at CO₂ levels crossing the 415 ppm mark in 2020, when an El Niño is forecast to come, as discussed in an earlier post.


The added trend in the image points at CO₂ levels crossing 1200 ppm before the end of the century, triggering the cloud feedback tipping point that by itself could push up global temperatures by 8°C, within a few years. Importantly, the clouds feedback starts at 1200 ppm CO₂-equivalent. Besides a CO₂ rise, further elements could contribute to the 1200 ppm CO₂e tipping point getting reached, such as albedo changes due to disappearing Arctic sea ice and seafloor methane releases from a rapidly-warming Arctic Ocean.

In conclusion, a huge temperature rise could eventuate much earlier than by the end of the century. The image below illustrates the potential for a rise of 18°C or 32.4°F by 2026.

[ from an earlier post ]
As discussed in a recent post, a 2020 El Niño could be the catalyst triggering huge methane releases from the Arctic Ocean seafloor starting in 2020 and resulting in such a 18°C (or 32.4°F) temperature rise within a few years time. To put this into perspective, an earlier post concluded that humans will likely go extinct at a 3°C rise, as such an abrupt rise will make habitat for humans (and many other species) disappear.

In the video below, John Davis describes some of the extreme weather events that he experienced recently. “Disasters like this are man-made now”, John says, “they're not natural disasters. This is caused by climate change.”



Meanwhile, a recent study found that the consensus among research scientists on anthropogenic global warming has grown to 100%, based on a review of 11,602 peer-reviewed articles on “climate change” and “global warming” published in the first 7 months of 2019.

This further confirms the probability or likelihood that emissions by people are causing global warming, from a likely danger to certain danger. Furthermore, as discussed in many earlier posts, there are two additional dimensions to the danger of climate change; the severity of the impact makes it not merely a catastrophic danger, it is an existential threat; finally, regarding timescale, the danger is not just near, the danger is imminent and in many respects we're already too late.


Above image expresses this visually, with the red area depicting where we are now. There were readability problems with the text on the sides of the cube, reason why a version without text and the color on the sides was posted in an earlier post.

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


Links

• UN news release
https://www.unenvironment.org/news-and-stories/press-release/cut-global-emissions-76-percent-every-year-next-decade-meet-15degc

• Paris Agreement
https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement

• United Nations Environment Programme (UNEP) - Emissions Gap Report
https://www.unenvironment.org/resources/emissions-gap-report-2019

• UNEP video: On the brink: Emissions Gap Report findings in 60 seconds
https://www.unenvironment.org/news-and-stories/video/brink-emissions-gap-report-findings-60-seconds

• WMO - Greenhouse gas concentrations in atmosphere reach yet another high
https://public.wmo.int/en/media/press-release/greenhouse-gas-concentrations-atmosphere-reach-yet-another-high

• NOAA Trends in Atmospheric Carbon Dioxide
https://www.esrl.noaa.gov/gmd/ccgg/trends/data.html

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

• 2020 El Nino could start 18°C temperature rise
https://arctic-news.blogspot.com/2019/11/2020-el-nino-could-start-18-degree-temperature-rise.html

• Scientists Reach 100% Consensus on Anthropogenic Global Warming
https://journals.sagepub.com/doi/full/10.1177/0270467619886266

• The Threat Of Arctic Albedo Change
https://arctic-news.blogspot.com/2016/09/the-threat-of-arctic-albedo-change.html

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




Sunday, September 8, 2019

Arctic Ocean overheating


The Arctic Ocean is overheating, as illustrated by above image.
[ from earlier post ]

Heating of the water in the Arctic Ocean is accelerating, as illustrated by above map that uses 4-year smoothing and that shows temperatures in the Arctic that are up to 4.41°C hotter than the average global temperature during 1880-1920.

The NOAA image on the right shows the sea surface temperature difference from 1961-1990 in the Arctic at latitudes 60°N - 90°N on September 7, 2019.

Where Arctic sea ice disappears, hot water emerges on the image, indicating that the temperature of the ocean underneath the sea ice is several degrees above freezing point.

The nullschool.net image on the right shows sea surface temperature differences from 1981-2011 on the Northern Hemisphere on September 8, 2019, with anomalies reaching as high as 15.2°C or 27.4°F (near Svalbard, at the green circle).

Accelerating heating of the Arctic Ocean could make global temperatures skyrocket in a matter of years.

Decline of the sea ice comes with albedo changes and further feedbacks, such as the narrowing temperature difference between the North Pole and the Equator, which slows down the speed at which the jet stream circumnavigates Earth and makes the jet stream more wavy.


Disappearance of the sea ice also comes with loss of the buffer 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. Once the sea ice is gone, further heat must go elsewhere.

[ click on images to enlarge ]
The Naval Research Laboratory image on the right shows a forecast for Sep. 8, 2019, run on Sep. 7, 2019, of the thickness of the sea ice. Sea ice has become terribly thin, indicating that the heat buffer constituted by the sea ice has effectively gone. Only a very thin layer of sea ice remains in place throughout much of the Arctic Ocean.

This remaining sea ice is stopping a lot of ocean heat from getting transferred to the air, so the temperature of the water of the Arctic Ocean is now rising rapidly, with the danger that some of the accumulating ocean heat will reach sediments at the seafloor and cause eruptions of huge amounts of methane.


This situation comes at a time that methane levels are very high globally. Mean global methane levels were as high as 1911 parts per billion on the morning of September 3, 2019, a level recorded by the MetOp-1 satellite at 293 mb (image below).


[ from an earlier post ]
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.

Compared to carbon dioxide, methane is some 150 times as potent as a greenhouse gas during the first few years after release.

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.

In total, global heating by as much as 18°C could occur by the year 2026 due to a combination of elements, including albedo changes, loss of sulfate cooling, and methane released from the ocean seafloor.

from an earlier post (2014)  

In the image below, from an earlier post, a global warming potential (GWP) of 150 for methane is used. Just the existing carbon dioxide and methane, plus seafloor methane releases, would suffice to trigger the clouds feedback tipping point to be crossed that by itself could push up global temperatures by 8°C, within a few years time, adding up to a total rise of 18°C by 2026.


Progression of heating could unfold as pictured below.

[ from an earlier post ]

In the video below, John Doyle describes out predicament.



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


Links

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

• Arctic Sea Ice Gone By September 2019?
https://arctic-news.blogspot.com/2019/07/arctic-sea-ice-gone-by-september-2019.html

• July 2019 Hottest Month On Record
https://arctic-news.blogspot.com/2019/08/july-2019-hottest-month-on-record.html

• Cyclone over Arctic Ocean - August 24, 2019
https://arctic-news.blogspot.com/2019/08/cyclone-over-arctic-ocean-august-24-2019.html

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


Sunday, September 1, 2019

Blueprints of future climate trends

Blueprints of future climate trends

Extreme GHG and temperature rise rates question linear climate projections

Andrew Glikson
Earth and climate scientist
Australian National University
geospec@iinet.net.au

Abstract

The extreme greenhouse gas (GHG) and temperature rise rates since the mid-1970th raise questions over linear climate projections for the 21st century and beyond. Under a rise of CO₂-equivalent reaching +500 ppm and 3.0 W/m⁻² relative to 1750, the current rise rates of CO₂ by 2.86 ppm per and recent global temperature rise rate (0.15-0.20°C per decade) since 1975 are leading to an abrupt shift in state of the terrestrial climate and the biosphere. By mid-21st century at >750 ppm CO₂-e climate tipping points indicated by Lenton et al. 2008 and Schellnhuber 2009 are likely to be crossed. Melting of the Greenland and Antarctic ice sheets has increased by a factor of more than 5 since 1979–1990. As the ice sheets and sea ice melt, the albedo flip between reflective ice surfaces and dark infrared-absorbing water results in significant increase of radiative forcing, and complete removal of Arctic sea ice would result in a forcing of about 0.7 W/m⁻² (Hudson, 2011). The confluence of climate events, including a breach of the circum-Arctic jet stream boundary and a polar-ward migration of climate zones at a rate of 56-111 km per decade, induce world-wide extreme weather events including bushfires, methane release from Arctic permafrost and sediments. For a climate sensitivity of 3±1.5°C per doubling of atmospheric CO₂, global warming has potentially reached between +2°C to +3°C above mean pre-industrial temperatures at a rate exceeding the fastest growth rate over the last 55 million years. As ice melt water flow into the oceans temperature polarities between warming continents and cooling tracts of ocean would further intensify extreme weather events under non-linear climate trajectories. The enrichment of the atmosphere in GHG, constituting a shift in state of the terrestrial climate, is predicted to delay the onset of the next glacial state by some 50,000 years.

GHG and temperature rise

The paleoclimate record suggests that no event since 55 million years ago, the Paleocene-Eocene Thermal Maximum (PETM), when global temperatures rose by more than +5 to +8°C over a period of ~20,000 years, with a subsequent warming period of up to 200,000 years, has been as extreme as atmospheric disruption since the onset of the industrial age about 1750 AD (the Anthropocene), accelerating since 1975. During this period greenhouse gas levels have risen from ~280 ppm to above >410 ppm and to 496 ppm CO₂-equivalent (Figure 1), the increase of CO₂ reaching near-47 percent above the original atmospheric concentration. However, linear climate change projections are rare in the recent climate history (Figure 2) and linear future climate projections may not account for the effects of amplifying feedbacks from land and oceans. Given an Anthropocene warming rate faster by ~X200 times than the PETM (Figure 3), linear warming trajectories such as are projected by the IPCC may overlook punctuated tipping points, transient reversals and stadial events.
Figure 1. Growth of CO₂-equivalent level and the annual greenhouse gas Index (NOAA AGGI).
Measurements of CO₂ to the 1950s are from (Keeling et al., 2008) and from air trapped in ice and
snow between CO₂ concentrations and radiative forcing from all long-lived greenhouse gases.

According to NOAA, GHG forcing in 2018 has reached 3.101 W/m⁻² relative to 1750 (CO₂ = 2.044 W/m⁻²; CH₄ = 0.512 W/m⁻²; N₂O = 0.199 W/m⁻²; CFCs = 0.219 W/m⁻²) with a CO₂-equivalent of 492 ppm (Figure 1). The rise in GHG forcing during the Anthropocene since about 1800 AD, intensifying since 1900 AD and sharply accelerating since about 1975, has induced a mean of ~1.5°C over the continents above pre-industrial temperature, or >2.0°C when the masking role of aerosols is discounted, implying further warming is still in store.

According to Hansen et al. 2008, the rise in radiative forcing during the Last Glacial Termination (LGT - 18,000 -11,000 years BP), associated with enhancing feedbacks, has driven GHG radiative forcing by approximately ~3.0 W/m⁻² and a mean global temperature rise of ~4.5°C (Figure 2), i.e. of similar order as the Anthropocene rise since about 1900. However the latter has been reached within a time frame at least X30 times shorter than the LGT, underpinning the extreme nature of current global warming.
Figure 2. (Hansen et al. 2008). Glacial-temperature and GHG forcing for the last 420,000 years based on the Vostok
ice core, with the time scale expanded for the Anthropocoene. The ratio of temperature and forcing scales is 1.5°C
per 1 W/m⁻². The temperature scale gives the expected equilibrium response to GHG change including slow feedback
surface albedo change. Modern forcings include human-made aerosols, volcanic aerosols and solar irradiance.
The CO₂-equivalent levels and radiative forcing levels constitute a rise from Holocene levels (~280 ppm CO₂) to >410 ppm compared with Miocene-like levels (300-600 ppm CO₂), at a rate reaching 2 to 3 ppm/year, within a century or so, driving the fastest temperature rise rate recorded since 55 million years ago (Figure 3).

Figure 3. A comparison between rates of mean global temperature rise during: (1) the last Glacial Termination
(after Shakun et al. 2012); (2) the PETM (Paleocene-Eocene Thermal Maximum, after Kump 2011);
(3) the late Anthropocene (1750–2016), and (4) an asteroid impact. In the latter instance temperature
due to CO₂ rise would lag by some weeks or months behind aerosol-induced cooling

Considering the transient mitigating albedo effects of clouds, seasonal land surface albedo, ice albedo, atmospheric aerosols including sulphur dioxide and nitrate, the potential rise of land temperature could have reached -0.4 to -0.9 W/m⁻² in 2018, masking approximately 0.6 to 1.3°C potential warming once the short lived aerosol effect is abruptly reduced.

Accelerated melting of the ice sheets

The fast rate of the Anthropocoene temperature rise compared to the LGT and PETM (Figure 3) ensues in differences in terms of the adaptation of flora and fauna to new conditions. The shift in state of the Earth’s climate is most acutely manifested in the poles, where warming leads to weakening of the jet stream boundaries which are breached by outflow of cold air fronts, such as the recent “Beast from the East” event, and penetration of warm air masses.

As the poles keep warming, to date by a mean of ~2.3°C, the shrinking of the ice sheets per year has accelerated by a factor of more than six fold (Figure 4). Warming of the Arctic is driven by the ice-water albedo flip, where dark sea-water absorbing solar energy alternates with high-albedo ice and snow, and by the weakening of the polar boundary and jet stream.

Greenland. The threshold of collapse of the Greenland ice sheet, retarded by hysteresis, is estimated in the range of 400-560 ppm CO₂, already transgressed at the current 496 ppm CO₂equivalent (Figure 4). The Greenland mass loss increased from 41 ± 17 Gt/yr in 1990–2000, to 187 ± 17 Gt/yr in 2000–2010, to 286 ± 20 Gt/yr in 2010–2018, or six fold since the 1980s, or 80 ± 6 Gt/yr per decade, on average.

Antarctica. The greenhouse gas level and temperature conditions under which the East Antarctic ice sheet formed during the late Eocene 45-34 million years ago are estimated as ~800–2000 ppm and up to 4 degrees Celsius above pre-industrial values, whereas the threshold of collapse is estimated as 600 ppm CO₂ or even lower. The total mass loss from the Antarctic ice sheet increased from 40 ± 9 Gt/yr in 1979–1990 to 50 ± 14 Gt/yr in 1989–2000, 166 ± 18 Gt/yr in 1999–2009, and 252 ± 26 Gt/yr in 2009–2017. Based on satellite gravity data, the East Antarctic ice sheet is beginning to breakdown in places (Jones 2019), notably the Totten Glacier (Rignot et al., 2019), which may be irreversible. According to Mengel and Levermann (2014), the Wilkes Basin in East Antarctica alone contains enough ice to raise global sea levels by 3–4 meters.

Figure 4. (A) New elevation showing the Greenland and Antarctic current state of the ice sheets accurate to a few meters in height, with elevation changes indicating melting at record pace, losing some 500 km³ of ice per-year into the oceans; (B) Ice anomaly relative to the 2002-2016 mean for the Greenland ice sheet (magenta) and Antarctic ice sheet (cyan). Data are from GRACE; (C) the melting of sea ice 1978-2017, National Snow and Ice Data Center (NCIDC)

C. Migration of climate zones

The expansion of warm tropical zones and the polar-ward migration of subtropical and temperate climate zones are leading to a change in state in the global climate pattern. The migration of arid subtropical zones, such as the Sahara, Kalahari and central Australian deserts into temperate climate zones ensues in large scale droughts, such in inland Australia and southern Africa. In the northern hemisphere expansion of the Sahara desert northward, manifested by heat waves across the Mediterranean and Europe (Figure 5).
Figure 5. (A) Migration of the subtropical Sahara climate zone (red spots) northward into the Mediterranean climate
zone leads to warming, drying and fires over extensive parts of Spain, Portugal, southern France, Italy, Greece and
Turkey, and to melting of glaciers in the Alps. Migration, Environment and Climate Change, International
Organization for Migration Geneva – Switzerland (GMT +1); Source: https://environmentalmigration.iom.int/maps

Figure 5. (B) Southward encroachment of Kalahari Desert conditions (vertical lines and red spots) leading to
warming and drying of parts of southern Africa. Source: https://environmentalmigration.iom.int/maps
Figure 5. (C) Drying parts of southern Australia, including Western Australia, South Australia and parts of the
eastern States, accompanied with increasing bushfires. Source: https://environmentalmigration.iom.int/maps
Climate extremes

Since the bulk of terrestrial vegetation has evolved under glacial-interglacial climate conditions, where GHG range between 180 - 300 ppm CO₂, global warming is turning large parts of Earth into a tinderbox, ignited by natural and human agents. By July and August 2019, as fires rage across large territories, including the Amazon forest, dubbed the Planet’s lungs as it enriches the atmosphere in oxygen. When burnt the rainforest becomes of source of a large amount of CO₂ (Figure 6.B), with some 72,843 fires in Brazil this year and extensive bushfires through Siberia, Alaska, Greenland, southern Europe, parts of Australia and elsewhere, the planet’s biosphere is progressively transformed. As reported: ‘Climate change is making dry seasons longer and forests more flammable. Increased temperatures are also resulting in more frequent tropical forest fires in non-drought years. And climate change may also be driving the increasing frequency and intensity of climate anomalies, such as El Niño events that affect fire season intensity across Amazonia.’

Extensive cyclones, floods, droughts, heat waves and fires (Figure 6.B) increasingly ravage large tracts of Earth. However, despite its foundation in the basic laws of physics (the black body radiation laws of Planck, Kirchhoff' and Stefan Boltzmann), as well as empirical observations around the world by major climate research bodies (NOAA, NASA, NSIDC, IPCC, World Meteorological Organization, Hadley-Met, Tindale, Potsdam, BOM, CSIRO and others), the anthropogenic origin, scale and pace of climate change remain subject to extensively propagated denial and untruths.

Figure 6. (A) Extreme weather events around the world 1980-2018,
including earthquakes, storms, floods, droughts. Munich Re-insurance.
Figure 6. (B) A satellite infrared image of South America fires (red dots) during July and August, 2019, NASA.

An uncharted climate territory

Whereas strict analogies between Quaternary and Anthropocene climate developments are not possible, elements of the glacial-interglacial history are relevant for an understanding of current and future climate events. The rise of total greenhouse gas (GHG), expressed as CO₂-equivalents, to 496 ppm CO₂-e (Figure 1), within less than a century represents an extreme atmospheric event. It raised GHG concentrations from Holocene levels to the range of the Miocene (34–23 Ma) when CO₂ level was between 300 and 530 ppm. As the glacial sheets disintegrate, cold ice-melt water flowing into the ocean ensue in large cold water pools, a pattern recorded following peak interglacial phases over the last 450,000 years, currently manifested by the growth of cold regions in north Atlantic Ocean south of Greenland and in the Southern Ocean fringing Antarctica (Figure 7).

Warming of +3°C to +4°C above pre-industrial levels, leading to enhanced ice-sheet melt, would raise sea levels by at least 2 to 5 meters toward the end of the century and, delayed by hysteresis, likely by 25 meters in the longer term. Golledge et al. (2019) show meltwater from Greenland will lead to substantial slowing of the Atlantic overturning circulation, while meltwater from Antarctica will trap warm water below the sea surface, increasing Antarctic ice loss. Whereas the effect of low-density ice melt water on the surrounding oceans is generally not included in many models, depending on amplifying feedbacks, prolonged Greenland and Antarctic melting and consequent cooling of surrounding ocean sectors as well as penetration of freezing air masses through weakened polar boundaries may have profound effect on future climate change trajectories (Figure 8).

Figure 7. (A) Global warming map (NASA 2018). Note the cool ocean regions south of Greenland and 
along the Antarctic. Credits: Scientific Visualization Studio/Goddard Space Flight Center; 
(B) 2012 Ocean temperatures around Antarctica (NASA 2012).
Climate projections for 2100-2300 by the IPCC AR5 Synthesis Report, 2014 portray predominantly linear to curved models of greenhouse gas, global temperatures and sea level changes. These models however appear to take limited account of amplifying feedbacks from land and ocean and of the effects of cold ice-melt on the oceans. According to Steffen et al. (2018) “self-reinforcing feedbacks could push the Earth System toward a planetary threshold” and “would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene”.

Amplifying feedbacks of global warming include:
  • The albedo-flip of melting sea ice and ice sheets and the increase of the water surface area and thereby sequestration of CO₂. Hudson (2011) estimates a rise in radiative forcing due to removal of Arctic summer sea ice as 0.7 W/m², a value close to the total of methane release since 1750.
  • Reduced ocean CO₂ intake due to lesser solubility of the gas with higher temperatures.
  • Vegetation desiccation and burning in some regions, and thereby released CO₂ and reduced evaporation and its cooling effect. This factor and the increase of precipitation in other regions lead to differential feedbacks from vegetation as the globe warms (Notaro et al. 2007).
  • An increase in wildfires, releasing greenhouse gases (Figure 6).
  • Release of methane from permafrost, bogs and sediments and other factors.
Linear temperature models appear to take limited account of the effects on the oceans of ice melt water derived from the large ice sheets, including the possibility of a significant stadial event such as already started in oceanic tracts fringing Greenland and Antarctica (Figure 7) and modeled by Hansen et al, (2016). In the shorter to medium term sea level rises would ensue from the Greenland ice sheet (6-7 meter sea level rise) and West Antarctic ice sheet melt (4.8 meter sea level rise). Referring to major past stadial events, including the 8200 years-old Laurentian melt and the 12.7-11.9 younger dryas event, a protracted breakdown of parts of the Antarctic ice sheet could result in major sea level rise and extensive cooling of southern latitudes and beyond, parallel with warming of tropical and mid-latitudes (Figure 8) (Hansen et al. 2016). The temperature contrast between polar-derived cold fronts and tropical air masses is bound to lead to extreme weather events, echoed among other in Storms of my grandchildren (Hansen, 2010).

Figure 8. (A) Model Surface-air temperature (°C) for 2096 relative to 1880–1920 (Hansen et al. 2016).
The projection betrays major cooling of the North Atlantic Ocean, cooling of the circum-Antarctic Ocean
and further warming in the tropics, subtropics and the interior of continents; (B) Modeled surface-air
temperatures (°C) to 2300 AD relative to 1880–1920 for several ice melt rate scenarios, displaying a stadial cooling event at a time dependent on the ice melt doubling time (Hansen et al., 2016). Courtesy Prof James Hansen;.
Within and beyond 2100-2300 projections (Figure 8.A, B) lies an uncharted climate territory, where continuing melting of the Antarctic ice sheet, further cooling of neighboring sectors of the oceans and climate contrasts with GHG-induced warming of land areas (Figure 8.A), ensue in chaotic climate disruptions (Figure 8.B). Given the thousands to tens of thousands years longevity of atmospheric greenhouse gases (Solomon et al., 2009; Eby et al 2009), the onset of the next ice age is likely to be delayed on the scale of tens of thousands of years (Berger and Loutre, 2002) through an exceptionally long interglacial period (Figure 9).

These authors state: ‘The present day CO₂ concentration (now >410 ppm) is already well above typical interglacial values of ~290 ppmv. This study models increases to up to 750 ppmv over the next 200 years, returning to natural levels by 1000 years. The results suggest that, under very small insolation variations, there is a threshold value of CO₂ above which the Greenland Ice Sheet disappears. The climate system may take 50,000 years to assimilate the impacts of human activities during the early third millennium. In this case, an “irreversible greenhouse effect” could become the most likely future climate. If the Greenland and west Antarctic Ice Sheets disappear completely, then today’s “Anthropocene” may only be a transition between the Quaternary and the next geological period.’

Figure 9. Simulated Northern Hemisphere ice volume (increasing downward) for the period 200,000 years BP to 130,000 years in the future, modified after a part of Berger and Loutre 2002. Time is negative in the past and positive in the future. For the future, three CO2 scenarios were used: last glacial-interglacial values (solid line), a human-induced concentration of 750 ppm (dashed line), and a constant concentration of 210 ppm inducing a return to a glacial state (dotted line).
As conveyed by leading scientists “Climate change is now reaching the end-game, where very soon humanity must choose between taking unprecedented action or accepting that it has been left too late and bear the consequences” (Prof. Hans Joachim Schellnhuber) …“We’ve reached a point where we have a crisis, an emergency, but people don’t know that ... There’s a big gap between what’s understood about global warming by the scientific community and what is known by the public and policymakers” (James Hansen).

Climate scientists find themselves in a quandary similar to medical doctors, committed to help the ill, yet need to communicate grave diagnoses. How do scientists tell people that the current spate of extreme weather events, including cyclones, devastating islands from the Caribbean to the Philippine, floods devastating coastal regions and river valleys from Mozambique to Kerala, Pakistan and Townsville, and fires burning extensive tracts of the living world, can only intensify in a rapidly warming world? How do scientists tell the people that their children are growing into a world where survival under a mean temperature higher than +2 degrees Celsius (above pre-industrial temperature) is likely to be painful and, in some parts of the world, impossible, let alone under +4 degrees Celsius projected by the IPCC?

Summary and conclusions
  1. The current growth rate of atmospheric greenhouse gas is the fastest recorded for the last 55 million years.
  2. By the mid-21st century, at the current CO₂ rise rates of 2 to 3 ppm/year, a CO₂-e level of >750 ppm is likely to transcend the climate tipping points indicated by Lenton et al. 2008 and Schellnhuber 2009.
  3. The current extreme rise rates of GHG (2.86 ppm CO₂/year) and temperature (0.15-0.20°C per decade since 1975) raise doubt with regard to linear future climate projections.
  4. Global greenhouse gases have reached a level exceeding the stability threshold of the Greenland and Antarctic ice sheets, which are melting at an accelerated rate.
  5. Allowing for the transient albedo-enhancing effects of sulphur dioxide and other aerosols, mean global temperature has reached approximately 2.0 degrees Celsius above per-industrial temperatures.
  6. Due to hysteresis the large ice sheets would outlast their melting temperatures.
  7. Land areas would be markedly reduced due to a rise to Miocene-like sea levels of approximately 40±15 meters above pre-industrial levels.
  8. Cold ice melt water flowing from the ice sheets into the oceans at an accelerated rate is reducing temperatures in large tracts in the North Atlantic and circum-Antarctic.
  9. Strong temperature contrasts between cold polar-derived and warm tropical air and water masses are likely to result in extreme weather events, retarding habitats and agriculture over coastal regions and other parts of the world.
  10. In the wake of partial melting of the large ice sheets, the Earth climate zones would continue to shift polar-ward, expanding tropical to super-tropical regions such as existed in the Miocene (5.3-23 million years ago) and reducing temperate climate zones and polar ice sheets.
  11. Current greenhouse gas forcing and global mean temperature are approaching Miocene Optimum-like composition, bar the hysteresis effects of reduced ice sheets (Figure 4.A).
  12. The effect of high atmospheric greenhouse gas levels would be for the next ice age to be delayed on a scale of tens of thousands of years, during which chaotic tropical to hyperthermal conditions would persist until solar radiation and atmospheric CO₂ subsided below ~300 ppm.
  13. Humans will survive in relatively favorable parts of Earth, such as sub-polar regions and sheltered mountain valleys, where gathering of flora and hunting of remaining fauna may be possible.

A Postscript

The author, while suggesting the projections made in this paper are consistent with the best climate science with which he is aware, sincerely hopes the implications of these projections would not eventuate.