Thursday, November 4, 2021

The exclusion of climate science from COP meetings

 by Andrew Glikson

There can be little doubt that, had the US, China and Russia been on the same page, an advanced agreement was likely to be reached at COP26, but since it is not, the collapse can be laid at the feet of human tribalism and eternal conflict since the dawn of civilization, ultimately leading to a mass extinction of species.

Climate scientists have practically been excluded from COP meetings, dominated as they are by economists, lawyers and politicians. To date no address has been made by leading climate scientists, including authorities such as James Hansen, Michael Mann, Joachim Schellnhuber, Will Steffen and other, leaving delegates and populations unaware of the ultimate consequences of global climate devastation.

With the exception of David Attenborough and references to “one minute to mid-night”, the science-based projections of global heating have only received faint echoes among the assembly of warring tribes at COP-26, dominated by nationalism, vested interests and sheer ignorance of the current trend, which can only culminate in the end of civilization.

The futility of making political decisions regarding future carbon emissions while continuing to grow fossil fuel industries is manifest (Figure 1).

Figure 1. Global CO₂ emissions by fuel (Global Carbon Project)

The lessons from climate science indicate:
  1. While politicians talk about a 1.5°C target, the mean global temperature has already exceeded this level and likely approaches 2°C when the transient short-term masking effects of aerosols are accounted for. Thus Hansen and Sato (2012) estimate aerosol to lower global temperatures by between -1.0°C and -1.2°C, which implies the real mean global temperatures are close to +2°C above pre-industrial level. By contrast, references to the NASA’s ~1.02°C warming can be compared to a measurement of a patient’s body temperature only after they take a dose of aspirin. Furthermore, this NASA anomaly is measured from 1951-1980, whereas the Paris Agreement calls for a pre-industrial base.

  2. Whereas the critical need for emissions reduction is central to climate negotiations, the effects of cumulative concentration of GHG in the atmosphere (CO₂ + equivalent CH₄, N₂O, etc), which trigger amplifying feedbacks from land and ocean, remains hardly tackled. The current CO₂-equivalent level of >500 ppm (Figure 2), which is near X1.8 times the pre-industrial level of ~280 ppm CO₂, is generating amplifying feedbacks. According to a climate sensitivity estimate of 3 ± 1.5°C per doubling of CO₂ the equilibrium rise in temperature could be approaching +3°C.

  3. The role of amplifying GHG feedbacks from land and oceans, leading to enhanced heating, appears to be neglected in climate talks, including:
    - A decline in the polar albedo (reflection) due to large-scale lateral and vertical melting of ice;
    Reduced CO₂ intake by warming oceans. Currently the oceans absorb between 35-42% of all CO₂ and around 90% of the excess heat;
    - Warming, desiccation, deforestation and fires over land areas;
    - Release of methane from melting permafrost and from polar sediments;
    - An increase in evaporation, particularly in arid zones, raising atmospheric vapor levels, which enhances the greenhouse gas effect.

  4. IPCC-based climate trends are mostly linear, yielding an impression that overshooting of the warming trend is capable of being reversed within acceptable time scales, projections which neglect the likelihood of tipping points of no return. The time scales for attempts to cool the atmosphere may exceed the longevity of civilization. The weakening of the Arctic jet stream, allowing air and water masses of contrasted temperatures to cross the Arctic boundary, leads to disruptions such as the freezing “beast from the east” fronts that hit North America and Europe and Arctic wildfires. The flow of ice melt water from Greenland and Antarctica into the oceans may result in marked transient temperature reversals in the oceans, extending onto land.
While neglecting the consequences of runaway global warming, discussions continue of the price of mitigation and adaptation, i.e. the price of habitability of Earth, proceeding to huggle in terms akin to corner store grocers. Elsewhere, much of the media appears to be preoccupied with the price of submarines, deadly weapons in futile wars, ironically more suitable for coastal surveys of regions flooded by an inevitable sea level rise on the scale of many meters.



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

Tuesday, October 26, 2021

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


Friday, October 15, 2021

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

• NOAA Sunspots

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

• Pre-industrial

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

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

Tuesday, October 5, 2021

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:
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