Amplifying feedbacks from land and ocean may render emission reductions insufficient

by Andrew Glikson

Figure 1. Comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO₂ has increased since the Industrial Revolution. (Credit: NASA, data: Luthi, D., et al. 2008; Etheridge, D.M., et al. 2010; Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.)

[ Figure 2. from earlier post ]

While the world, for very good reasons, is relying on medical research in order to save the lives of millions, the “powers to be” are hardly listening to what climate science is saying about the existential threat to billions posed by global heating.

Since 1751 the world has emitted over 1.5 trillion tonnes of CO₂. The atmospheric level of CO₂ was 413.2 parts per million (ppm) in 2020, growing at peak rates of 2.5-3.0 ppm/year, representing the greatest acceleration since the dinosaur mass extinction of 66 million years ago.

“The last time the Earth experienced a comparable concentration of CO₂ was 3-5 million years ago, when the temperature was 2-3°C warmer and sea level was 10-20 meters higher than now”, Prof. Petteri Taalas, Secretary-General of the World Meteorological Organization said in a news release.

The rise of atmospheric greenhouse gases to levels >>400 ppm has the potential to rapidly transform the atmosphere into conditions similar to those of the Miocene and even the Eocene — a catastrophe for life on Earth.

According to the IPCC “the effects of +1.5°C of warming (relative to mean pre-industrial temperature), plus the projection that half a degree Celsius, 2°C versus 1.5°C, will make quite a considerable difference in the livability of planet Earth […] the trajectory of warming based on historical trends will see increases certainly above 3°C and possibly much more if emissions aren’t cut […] the whole world must become carbon neutral by 2050.”

Figure 3. Global mean temperature deviation from 1880-1900: all 19 years since 2002 rank among the 20 warmest. (Image by Munichre.com based on NOAA data)

Average global temperatures may be misleading. According to NASA, “The impacts of climate change haven’t been spread evenly around our planet [..] The strongest warming is happening in the Arctic during its cool seasons, and in Earth’s mid-latitude regions during the warm season”. The reduced albedo of the melting polar ice sheets are driving global warming at a rate faster than elevated temperatures in the tropics.

While the focus of international policies is on the essential reduction in emissions, it is the cumulative effect of greenhouse gases in the atmosphere which drives global warming. The 2020 CO₂ level being 413.30 ppm, exceeding pre-industrial levels by more than 133 ppm. Unless civilization finds a way to down-draw CO₂ from the atmosphere, amplifying feedbacks from land and oceans will continue to heat the Earth, due to:

1. The polar albedo (reflection) decline due to large-scale lateral and vertical melting of ice;
2. Reduced CO₂ intake by the warming oceans. Currently the oceans absorb between 35-42 percent of all CO₂ emitted to the atmosphere and around 90 percent of the excess heat;
3. Warming, desiccation, deforestation and fires over land areas;
4. Release of methane from melting of permafrost and from polar sediments;
5. An increase in evaporation, particularly in arid zones, raising atmospheric vapor levels which enhances the greenhouse gas effect.

These feedbacks result in an accelerated climate change, as projected by Wally Broecker and others, and potentially in mass extinction. A climate chain-reaction is believed to have pertained about 55 million years ago during the Paleocene-Eocene thermal maximum (PETM). According to Peter Ward and others, early examples of mass extinctions triggered by biological processes were related to ocean anoxia and acidification leading to methane (CH₄) and hydrogen sulfate (H₂S) release by “purple” and “green” algae and sulphur bacteria. In a similar sense anthropogenic global warming constitutes a geological/biological process for which the originating organism (sapiens) has not to date discovered an effective method of control.

Sequestration of CO₂ is essential due to the amplifying feedbacks of global warming, which are pushing temperatures up in a chain reaction-like process.

Whereas the aim of the Glasgow COP26 Conference is to reach agreement for limiting mean global temperature to <1.5°C, the short-term mitigating effect of aerosols on global temperatures, namely ~0.5 – 1.0°C, means global temperatures are already nearing ~2.0°C.

Hopes that the Glasgow climate meeting would help save the world from a climate catastrophe would depend on:

1. Binding agreements for the most abrupt reduction of carbon emissions rates to pre-peak rates of about 1 ppm/year or lower, requiring a world-wide transformation of agricultural, industrial and transport systems;
2. Attempts at sequestration/drawdown of greenhouse gases aimed at reducing the current atmospheric CO₂ levels to near-350 ppm or lower (Hansen et al. 2013). Whereas the engineering efforts and costs of such attempts cannot be overestimated, such could in principle be achieved by diversion from the astronomical budgets invested in defense industries, eventually aimed at future wars and further catastrophe.

The concept of a “carbon budget”, allowing the world to constrain emission to a particular amount of greenhouse gases in order to limit warming, does not take into account the amplifying feedbacks to warming from land and oceans, nor possible reversals due to the flow of cold water from melting ice sheets into the oceans.

The critical criterion definitive of global warming, namely the atmospheric concentration of greenhouse gases, rising by nearly ~50% since pre-industrial time, is only rarely mentioned. Nor are other quantitative measures of climate change, such as the level of methane and nitrous oxide, which have risen by about 3-fold being highlighted. While opinions by journalists, politicians, economists and social scientists proliferate, less attention is given to what is indicated by climate science. This reluctance renders the global response to the looming climate calamity increasingly irrelevant.

It is the ethical duty of scientists to advice governments and the public of dangerous developments, but it incurs a heavy price to pay for communicating worrying news Cassandra-like, including social and professional isolation. Don’t envy scientists aware of the ultimate consequences of global warming. Many have either self-censored or their work suppressed or dismissed within institutions and the media, including in governments and academia.

The reluctance of too many to undertake effective defense of the Earth’s climate, since nearly 40 years ago, can only culminate in devastation of the planet’s life support systems—one of the greatest catastrophes the planet has undergone since the dinosaur extinction about 66 million years ago.

Andrew Glikson

A/Prof. Andrew Glikson

Earth and Paleo-climate scientist
School of Biological, Earth and Environmental Sciences
The University of New South Wales,
Kensington NSW 2052 Australia

Books:
The Asteroid Impact Connection of Planetary Evolution
https://www.springer.com/gp/book/9789400763272
The Archaean: Geological and Geochemical Windows into the Early Earth
https://www.springer.com/gp/book/9783319079073
Climate, Fire and Human Evolution: The Deep Time Dimensions of the Anthropocene
https://www.springer.com/gp/book/9783319225111
The Plutocene: Blueprints for a Post-Anthropocene Greenhouse Earth
https://www.springer.com/gp/book/9783319572369
Evolution of the Atmosphere, Fire and the Anthropocene Climate Event Horizon
https://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
https://www.springer.com/us/book/9783319745442
The Event Horizon: Homo Prometheus and the Climate Catastrophe
https://www.springer.com/gp/book/9783030547332
The Fatal Species: From Warlike Primates to Planetary Mass Extinction
https://www.springer.com/gp/book/9783030754679

Will COP26 in Glasgow deliver?

September 2021 was the second warmest September on record, after September 2020, according to NASA, Copernicus and James Hansen, despite the cooling effect of the current La Niña. Above NASA map shows that the Arctic Ocean was hit severely by high temperatures.

The NASA map shows an anomaly of 0.96°C compared to 1951-1980. With COP26 to be held in Glasgow, from October 31 to November 12, 2021, it's important to realize that using the period from 1951 to 1980 as a base is not the same as pre-industrial. So, how much has the temperature risen from pre-industrial and what are the prospects? Will COP26 deliver?

[ from earlier post ]

Let's do the calculations once more. The trend in the image below indicates that the NASA data need to be adjusted by 0.29°C to change the base from 1951-1980 to 1900. 

Of course, 1900 is still not pre-industrial. The chart below shows three trends:

1. The green trend is based on unadjusted NASA data (1951-1980 base). 
2. The lilac trend is based on data adjusted by 0.79°C for a 1750 base, for higher polar anomalies and for ocean air temperatures. The lilac trend shows that the 1.5°C threshold was already crossed when the Paris Agreement was adopted in 2015, while a 3°C could be crossed well before 2050.
3. The red trend is based on data adjusted by 1.28°C, adding an extra 0.49°C to the lilac data for a 3480 BC base. The red trend shows that the 2°C threshold was already crossed when the Paris Agreement was adopted in 2015, while a 5°C anomaly could crossed by 2060.

The way these adjustments are calculated is also discussed in an earlier post and at the pre-industrial page.

Another thing to consider is the impact of short-term variables. The chart below shows the same red data, i.e. 1.28°C adjusted, with two trends added: a red trend based on 1880-Sept. 2021 data, and a blue trend based on 2015-Sept. 2021 data.

The blue trend is more in line with short-term variables, such as El Niño, sunspots and volcanoes. The blue trend shows that temperatures are currently suppressed.

Within a few years time, sunspots can be expected to reach the peak of their current cycle, and they are looking stronger than forecast, as illustrated by the image on the right, adapted from NOAA.

Furthermore, the next El Niño could raise surface temperatures significantly. The image below indicates that the difference between the top of El Niño and the bottom of La Niña could be more than half a degree Celsius.

As the image on the right shows, NOAA expects the current La Nina to deepen and to continue well into 2022. 

The threatening situation is that we'll go into the next El Niño, while sunspots are increasing and while the aerosol impacts may go from dimming into further driving up temperatures. A huge temperature rise could occur as the sulfates fall away that are currently co-emitted by traffic and industry, while at the same time releases of other aerosols such as black and brown carbon can increase dramatically as more wood burning and forest fires take place.

Such short-term natural variability can furthermore act as a catalyst, causing numerous feedbacks to kick in with ever greater ferocity.

Such feedbacks can result in collapse of Arctic sea ice and eruption of huge quantities of carbon dioxide, methane and nitrous oxide, further driving up the temperature rise abruptly, as illustrated by the blue trend in the image further above. 

The World Meteorological Organization (WMO) has released 2020 figures for carbon dioxide (CO₂), which reached 413.2 parts per million (ppm) in 2020, 149% of the 1750 level. Methane (CH₄) reached 1889 parts per billion (ppb) in 2020, 262% of the 1750 level and nitrous oxide (N₂O) reached 333.2 ppb, 123% of the 1750 level.

“The last time the Earth experienced a comparable concentration of CO₂ was 3-5 million years ago, when the temperature was 2-3°C warmer and sea level was 10-20 meters higher than now”, said WMO Secretary-General Prof. Petteri Taalas.

Sadly, the IPCC appears to have dramatically underplayed the gravity of the situation. The image on the right, from James Hansen, shows the gap between RCP 2.6 and added forcing since 1990.

The image below, from Tian et al. (2020), shows differences between the RCP and SSP pathways for nitrous oxide.

[ from earlier post ]

The image on the right, from an earlier post, illustrates the rise in nitrous oxide levels up April 2020.

Perhaps even more frightening is the situation regarding methane, as illustrated by the combination image below. The MetOp-2 satellite recorded some terrifying methane levels recently. On October 14, 2021 pm, a peak methane level of 4354 ppb was recorded at 293 mb (left panel), while a mean level of 2068 ppb was recorded at 367 mb (right panel). The images show only a partial cover of the globe, so there may be some problems with this satellite, yet it could be an ominous sign of things to come.

No images were available for the MetOp-2 satellite the next day, October 15, 2021. Further complicating things, no images were available for two further satellites either, the SNPP satellite and the NOAA 20 satellite. 

Very few methane measurements are available for the Arctic. Measurements are available from only a handful of ground stations, i.e. flask and in situ data at Barrow, Alaska, and flask data at Cold Bay, Alaska, at Ny-Alesund, Svalbard, at Alert, Nunavut, and at Summit, Greenland, while one-off measurements have been taken by vessels and by aircraft, such as at Poker Flats, near Fairbanks, Alaska. Availability of flask data stopped in 1997 at Mould Bay, Northwest Territories, and in 2018 at Tiksi, Russia. Moreover, to monitor methane releases from the seafloor of the Arctic Ocean, it is essential to have more continuous measurements taken at numerous altitudes by polar-orbiting satellites. And of course, taking measurements alone is not enough to reduce the danger.

Meanwhile, NOAA has put up a notice that IASI data and products from Metop-A (MetOp-2) will no longer update and the satellite will be retired on November 15, 2021.

Data from the MetOp-1 satellite are still available. The animation on the right shows methane as recorded by the MetOp-1 satellite on October 16, 2021 pm from 972 mb (roughly sea level) to 766 mb (some 2.3 km or 7,546 ft).

The magenta color indicates the highest methane levels. The animation shows that magenta-colored areas (with the highest levels) first show up over the Arctic Ocean, close to sea level. When rising up further toward the Tropopause, beyond what the animation shows, even more magenta shows up, with methane moving toward the Equator, as the Tropopause is higher closer to the Equator. 

The image on the right shows the situation on October 25, 2021 am at 295 mb, which is at an altitude of about 9 km (5.592 miles), where the tropopause starts over the North Pole. 

The image shows that the mean global methane level at this altitude was 1958 ppb. Very high methane levels show up over the high Arctic, as indicated by the magenta color. The image further shows the strong accumulation of methane at this altitude.

Below is an image by Copernicus, showing methane at 500 hPa on October 16, 2021 at 03 UTC. 

As said, the IPCC sadly keeps downplaying the temperature rise and the threat of a huge rise soon, while promoting the idea that there was a “carbon budget” to be divided among polluters that would enable polluters to keep polluting for decades to come. Hopefully, politicians at COP26 will do the right thing. The situation is dire and calls for the most comprehensive and effective action, as described at the Climate Plan.

Links

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

• Glasgow Climate Change Conference (COP26)
https://unfccc.int/process-and-meetings/conferences/glasgow-climate-change-conference

• IPCC special report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways (SR1.5)
https://report.ipcc.ch/sr15/

• IPCC AR6
https://www.ipcc.ch/assessment-report/ar6/

• Paris Agreement, adopted 2015
https://unfccc.int/sites/default/files/resource/docs/2015/cop21/eng/l09r01.pdf
https://arctic-news.blogspot.com/2015/12/paris-agreement.html

• WMO - Greenhouse Gas Bulletin: Another Year Another Record

https://public.wmo.int/en/media/press-release/greenhouse-gas-bulletin-another-year-another-record
https://library.wmo.int/index.php?lvl=notice_display&id=21975

• MetOp satellites
https://www.ospo.noaa.gov/Products/atmosphere/soundings/iasi/

• Copernicus - methane
https://atmosphere.copernicus.eu/charts/cams/methane-forecasts

• September Temperature Update & COP 26 - 14 October 2021 - by James Hansen and Makiko Sato

http://www.columbia.edu/~mhs119/Temperature/Emails/September2021.pdf

• NOAA Sunspots

https://www.swpc.noaa.gov/phenomena/sunspotssolar-cycle

• A comprehensive quantification of global nitrous oxide sources and sinks - by Hanqin Tian et al. (2020)
https://www.nature.com/articles/s41586-020-2780-0

• NOAA - ENSO: Recent Evolution, Current Status and Predictions - October 11, 2021

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

• NOAA Monthly Temperature Anomalies Versus El Niño
https://www.ncdc.noaa.gov/sotc/global/202109/supplemental/page-4

• Is the IPCC creating false perceptions, again?

https://arctic-news.blogspot.com/2021/08/is-the-ipcc-creating-false-perceptions-again.html

• Pre-industrial

https://arctic-news.blogspot.com/p/pre-industrial.html

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

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

Glasgow and global warming to 2⁰C and beyond

by Andrew Glikson

“Burning all fossil fuels would create a different planet” (Hansen, 2016)

While at present the world is necessarily investing in medical research in order to save the lives of millions, global heating is threatening the lives of billions over the century, yet authorities are hardly listening to what climate science is projecting as the Earth is heating.

Since the Paris climate conference in April 2016, when the mean atmospheric carbon dioxide level reached 403.3 ppm, induced by annual emissions of some 400 billion tons of CO₂, the atmospheric level has risen to near 420 ppm, growing at peak rates of 2.5-3.0 ppm/year, the highest recorded since the dinosaur mass extinction of 66 million years ago.

Although the target of the Glasgow meeting is to reach agreement for limiting mean global temperature to 1.5⁰C, due to the short-term mitigating effect of ~0.5–1.0⁰C by aerosols on global temperatures mean global warming is already tracking toward 2⁰C (Figure 1).

Figure 1. Extreme heatwaves, like the one that affected Europe in the summer of 2006, are projected to become widespread at 1.5 degrees Celsius warming. This map, derived from NASA MODIS Terra satellite data, depicts the July 2006 land surface temperature anomaly with regard to the period from 2000-2012.

Hopes that the coming Glasgow climate meeting would help avert a disastrous climate catastrophe depend on:

1. Binding agreements for a drastic reduction of greenhouse gas emissions rates to pre-peak rates of about ~1ppm/year or lower, requiring world-wide transformation of agricultural, industrial and transport systems.
2. Attempts at sequestration/drawdown of CO₂ to near-350 ppm or lower (Hansen et al. 2013). Although the engineering efforts and the costs of such attempts cannot be overestimated, in principle such attempts could be achieved by a diversion of funds from the astronomical budgets invested in the military-industrial complex world-wide, currently just under $2 trillion, an underlying factor in previous world wars and ultimately aimed at future wars.

Sequestration of CO₂ is essential due to the amplifying feedbacks of global warming, which is pushing temperatures up in a chain reaction-like process, as follows:

• The polar albedo decline due to large-scale lateral and vertical melting of ice;
• Reduced CO₂ intake by the warming oceans. Currently the oceans absorb between 35-42 percent of all CO₂ emitted into the atmosphere and around 90 percent of the excess heat from the rise in greenhouse gases;
• Warming, desiccation, deforestation and fires over extensive areas;
• Release of methane from thawing permafrost and from polar sediments;
• An increase in evaporation, particularly in arid zones, raising atmospheric vapor levels, enhancing the greenhouse gas effect.

Mean global temperature however do not represent an accurate picture of the effects of global warming. According to NOAA the impacts of climate change haven’t been spread evenly around our planet … the strongest warming is happening in the Arctic during its cool seasons, and in Earth’s mid-latitude regions during the warm season.” (Figure 2).

Figure 2. Global climate changes to 1.5 and 2 degrees Celsius. Temperature change is not uniform across the globe. Projected changes are shown for the average temperature of the annual hottest day (top) and the annual coldest night (bottom) with 1.5 degrees Celsius of global warming (left) and 2 degrees Celsius of global warming (right) compared to pre-industrial levels. Image credit: NASA.

The acceleration of warming due to amplifying feedbacks from land and oceans, envisaged by Wally Broecker and others, leads a climate chain reaction such as is believed to have pertained about 55 million years ago during the Paleocene-Eocene thermal maximum (PETM). Peter Ward and others refer to early examples of mass extinctions triggered by biological processes related to ocean anoxia, acidification, release of methane (CH₄) and hydrogen sulphide (H₂S), and development of “purple” and “green” algae and sulphur bacteria. In a similar sense anthropogenic global warming constitutes a biological process which the originating organism, Homo sapiens, has not to date been able to limit.

The critical factor which drives climate change, namely the atmospheric concentration of greenhouse gases, which rose by near-50% since pre-industrial time, is only rarely mentioned by the media and by politicians. Nor are other quantitative measures of climate change, such as the level of methane and nitrous oxide, which were elevated about 3-fold, being highlighted. While opinions by journalists, politicians, economists and social scientists are widely promulgated, less attention is given to what is indicated by climate science, a reluctance rendering the global response to the looming climate calamity increasingly irrelevant.

Many scientists are reluctant to warn the public of the full implications of global heating for the habitability of Earth. Issuing public warnings Cassandra-like may incur a heavy price, including social and professional isolation, psychological effects and loss of professional position. Many either self-censor or were suppressed or dismissed within institutions. This includes a common reluctance by the media to publish climate articles.

According to John Schellnhuber, Germany’s former chief climate scientist: “The Earth system's responses to climate change appear to be non-linear… If we venture far beyond the 2 degrees guardrail, towards the 4 degrees line, the risk of crossing tipping points rises sharply”.

According to Hansen (NASA’s former chief climate scientist) et al. (2012) “Burning all fossil fuels would create a different planet than the one that humanity knows. The palaeoclimate record and ongoing climate change make it clear that the climate system would be pushed beyond tipping points, setting in motion irreversible changes, including ice sheet disintegration with a continually adjusting shoreline, extermination of a substantial fraction of species on the planet, and increasingly devastating regional climate extremes”.

Considering that the last glacial termination (LGT), i.e. the transition from the last ice age to the Holocene, incurred a rise of about 4 to 5 degrees Celsius over a period of about 7.5 kyr (0.00053 to 0.00066⁰C/year), the Anthropocene global warming (~+1.5⁰C in 270 years; 0.0055⁰C/year) is reaching an order of magnitude faster than the LGT within a century or so, constituting a recipe for a global disaster.

Andrew Glikson

A/Prof. Andrew Glikson

Earth and Paleo-climate scientist
School of Biological, Earth and Environmental Sciences
The University of New South Wales,
Kensington NSW 2052 Australia

Books:
The Asteroid Impact Connection of Planetary Evolution
https://www.springer.com/gp/book/9789400763272
The Archaean: Geological and Geochemical Windows into the Early Earth
https://www.springer.com/gp/book/9783319079073
Climate, Fire and Human Evolution: The Deep Time Dimensions of the Anthropocene
https://www.springer.com/gp/book/9783319225111
The Plutocene: Blueprints for a Post-Anthropocene Greenhouse Earth
https://www.springer.com/gp/book/9783319572369
Evolution of the Atmosphere, Fire and the Anthropocene Climate Event Horizon
https://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
https://www.springer.com/us/book/9783319745442
The Event Horizon: Homo Prometheus and the Climate Catastrophe
https://www.springer.com/gp/book/9783030547332
The Fatal Species: From Warlike Primates to Planetary Mass Extinction
https://www.springer.com/gp/book/9783030754679

The dilemma of climate scientists

by Andrew Glikson

“in private conversations, many climate scientists express far greater concern at the progression
of global warming and its consequences than they do in public” - Andrew Glikson (2016)

Bulletin of the Atomic Scientists

Many climate change models, including by the IPCC, appear to neglect or minimize the amplifying feedbacks of global warming, which are pushing temperatures upward in a chain reaction-like process, as projected by Wally Broecker and others.

A climate chain reaction is believed to have pertained about 55 million years ago (Paleocene-Eocene Thermal Maximum [PETM]).

During the Anthropocene (post-1750 and in particular post-1900) greenhouse gas and temperature growth rates levels exceeded those of the PETM and of the end of the last glacial termination (LGT). During 2010-2020 an acceleration of global warming is reflected by an anomalous rise in greenhouse gas levels and temperatures (Figure 1).

Figure 1. 1880-2020 temperature anomalies relative to the 1951-1980 base line (NASA, NOAA, Hadley, Berkeley)

According to Peter Ward and others early examples of mass extinctions triggered by biological processes were related to ocean anoxia and acidification leading to CH4 and H2S release by “purple” and “green” algae and sulphur bacteria. Likewise, anthropogenic global warming constitutes a geological/biological process for which the originating organisms (humans) have not to date been able to discover an effective method of control.

The critical criterion definitive of global warming is the atmospheric concentration of greenhouse gases, rising from 280 to 419 ppm, i.e. by about 49% since pre-industrial time, only rarely mentioned by the media and politicians. Other parameters of climate change, such as the level of methane and nitrous oxide, have risen about 3-fold. While opinions by journalists, politicians, economists and social scientists proliferate, less attention is given to what is indicated by climate science, rendering the global response to the looming calamity increasingly irrelevant.

Thus, whereas most models portray linear rise in temperature, the evidence for the breading of the circum-Arctic jet stream, allowing cold and warm fronts to cross the boundary, would result in high storminess in high latitudes.

“Most scientists agree that climate change is happening faster than predicted. More than one-third of the world’s soil, which produces 95% of the world’s food supply, is currently degraded. By 2035, outdoor air pollution is projected to be a top cause of environmentally-related deaths worldwide, and half the world’s population will face water shortages.” However, many scientists are reluctant to warn the public about the full consequences of accelerating global heating. Namely, as Joachim Schellnhuber, Germany’s chief climate scientist has stated, the existential risk to the life support systems of the planet.

There is a heavy price to pay for communicating distressing evidence, Cassandra-like, including psychological factors and/or social and professional isolation. Personal optimism may overcome realism. Some scientists are either self-censored or have their work suppressed or dismissed within institutions or by the media, including in government and academia. Some scientists have lost their position.

As cited in the article titled “When the End of Human Civilization Is Your Day Job“ … “Among many climate scientists, gloom has set in. Things are worse than we think, but they can't really talk about it”, and elsewhere “in private conversations, many climate scientists express far greater concern at the progression of global warming and its consequences than they do in public”. It is not uncommon to hear people criticizing climate scientists for not telling them more about the future climate, although when they are told, many recoil. Then there is the plethora of false promises by politicians.

As the world continues to spend $trillions each year on military preparation for war or nuclear war, resources needed if serious attempts are made for protection of life on Earth, despair sinks in.

But the world is now waking up to the climate calamity.

There must be hope.

Andrew Glikson

A/Prof. Andrew Glikson

Earth and Paleo-climate scientist
School of Biological, Earth and Environmental Sciences
The University of New South Wales,
Kensington NSW 2052 Australia

Books:
The Asteroid Impact Connection of Planetary Evolution
https://www.springer.com/gp/book/9789400763272
The Archaean: Geological and Geochemical Windows into the Early Earth
https://www.springer.com/gp/book/9783319079073
Climate, Fire and Human Evolution: The Deep Time Dimensions of the Anthropocene
https://www.springer.com/gp/book/9783319225111
The Plutocene: Blueprints for a Post-Anthropocene Greenhouse Earth
https://www.springer.com/gp/book/9783319572369
Evolution of the Atmosphere, Fire and the Anthropocene Climate Event Horizon
https://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
https://www.springer.com/us/book/9783319745442
The Event Horizon: Homo Prometheus and the Climate Catastrophe
https://www.springer.com/gp/book/9783030547332
The Fatal Species: From Warlike Primates to Planetary Mass Extinction
https://www.springer.com/gp/book/9783030754679

On borrowed time: How long to a Miocene-like tropical ~+4°C world?

On borrowed time: How long to a Miocene-like tropical ~+4°C world?

by A/Prof Andrew Glikson

Earth and climate scientist

Toward late this century global temperatures are likely to either reach super-tropical levels of >>14°C or/and extreme levels of storminess consequent on clashes between Arctic and Antarctic sourced cold and warm air and water masses.

Humans appear to be mainly concerned about any one issue at a time, and while COVID-19 is claiming the lives of millions Homo sapiens appears to be increasingly oblivious to the growing threat to billions of humans and to nature, including the inhabitability of large regions and extinguishment of habitats.

The almost universal assumption as if a reduction in greenhouse gas emissions is in itself sufficient to prevent further warming is misleading, since positive feedbacks from land and ocean would continue to raise greenhouse levels and temperatures.

Such feedback effects include:

1. increased evaporation with warming, water vapor being a greenhouse gas;
2. melting ice decreasing the albedo effect of Earth, exposing dark rock surfaces, reducing the albedo of the polar terrains and sea ice in surrounding oceans, enhancing infrared absorption and heating;
3. burnt and desiccated vegetation decreasing the albedo;
4. decreased absorption and solubility of CO₂ in warming oceans;
5. release of CO₂ and methane from drying vegetation, from melting permafrost and from bogs.

A critical parameter, rarely mentioned in the media, is the inexorable accelerating rise in atmospheric greenhouse gases. With CO₂ reaching 414.6 parts per million, CH₄ (methane) is reaching 1891.3 parts per billion and total greenhouse gas concentration of 500 parts per million, a level unknown since the Miocene about 5.3-23 million years ago.

With a Miocene CO₂ level in the range of ~400-500 parts per million and mean temperatures up to 18.4°C, the atmosphere is tracking toward super-tropical temperatures, which would render large regions uninhabitable.

Anthropocene temperature rise rates are at least an order of magnitude higher than the mean temperature rise since the Last Glacial Maximum:

• Given the current mean global land and ocean temperature of 14°C, i.e. 6.2°C warmer than the mean ~7.8°C temperature of the Last Glacial Maximum (LGM) (~19,000–23.000 years-ago), the mean warming of (~0.00026°C/year rate; 6°C/23.000 years) is an order of magnitude slower than during the Anthropocene.
• Late Holocene/Anthropocene: 1.04°C/250 years ~0.004°C/year). This relegates the current global warming to an unprecedented category during the last ~3 million years and longer.

Namely, at ~+4 degrees Celsius of warming toward later the 21st century the Earth’s mean surface land/ocean temperature would be warmer than tropical Miocene temperatures. A lag effect between the rise of greenhouse gases and temperature would delay but not prevent the worst effects of global warming.

But even before such high mean temperatures is reached, the weakened jet stream climate zone boundary, allowing penetration of cold and warm fronts, allowing clashes between air and water masses of contrasting temperatures, would lead to storminess, disrupting human agriculture and habitats, as is already happening in northern Europe and within the Arctic circle. 

How long would it take for global temperatures to rise to about ~4°C and higher would depend on:

1. The acceleration in rising concentration of greenhouse gases and the lag in consequent rising temperatures;
2. The extent to which ice melt flow from Greenland and Antarctica may slow down further warming in certain regions, such as the north Atlantic and the Southern Ocean;
3. Further anthropogenic emissions and/or draw-down of atmospheric CO₂.

From the continuing rise of atmospheric greenhouse concentrations (CO₂: 2020 – 414.62 ppm; 2021 - 416.96 ppm) to date global greenhouse gas emissions are hardly slowing down, nor have attempts at mitigation and/or sequestration been effective. In 2019, the world emitted roughly 36.44 billion metric tons (BMT) of carbon dioxide, compared to 14.83 BMT in 1970.

According to the head of the International Energy Agency no new oil, gas or coal development ought to take place if the world is to reach net zero by 2050. 

However, rising production of hydrocarbons in several regions, for example new drilling for oil in the North Sea, high production of oil and gas the USA, new coal mines in Australia and elsewhere cast doubt on the level of carbon emissions in future.

Conclusion: A rise in the mean global temperature to about 4 degrees Celsius or higher, as projected by IPCC, and/or a stormy climate consequent due to clashes between air and water masses of contrasting temperatures consequent on weakening of climate zone boundaries, are likely to progress through the 21st Century, severely disrupting natural and human habitats and species.

Andrew Glikson

A/Prof. Andrew Glikson

Earth and Paleo-climate scientist

School of Biological, Earth and Environmental Sciences
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
The Event Horizon: Homo Prometheus and the Climate Catastrophe
https://www.springer.com/gp/book/9783030547332

The Fatal Species: From Warlike Primates to Planetary Mass Extinction
https://www.springer.com/gp/book/9783030754679