Arctic News

Saturday, February 5, 2022

When will humans go extinct?

In a recent paper, Guy McPherson, Beril Sirmacek and Ricardo Vinuesa discuss Environmental thresholds for mass-extinction events. Authors point at an image by Song et al. (2021) that shows how major mass extinctions over the past 541 million years (the Phanerozoic) are linked to temperature rises higher than 5.2°C and rates of change higher than 10°C/Myr.

Earlier, a 2018 study by Strona & Bradshaw found that at 5°C rise, most life on Earth will be extinct (see box below on the right, from an earlier post).

In the video below, authors Guy McPherson, Beril Sirmacek and Ricardo Vinuesa discuss their analysis 'Environmental thresholds for mass extinction events'.

Authors point out that, next to temperature rise and rates of change, there are further variables such as rates of deforestation, ocean acidification and spreading of toxic substances that can additionally contribute to cause species to disappear.

Accordingly, many species are likely to go extinct at rises much lower than 5°C.

Humans - who depend on many species - could go extinct with a 3°C rise, as the above-mentioned earlier post concluded.

This makes it even more critical to assess how much the temperature has already risen from pre-industrial. As illustrated by the image below, we may already be more than 2°C above pre-industrial and face a potentially huge temperature rise over the next few years.

Below, the video associated with the analysis Environmental thresholds for mass-extinction events.

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

Links

• Environmental thresholds for mass-extinction events - by Guy McPherson, Beril Sirmacek and Ricardo Vinuesa (2022)
https://arxiv.org/abs/2108.08933

• Thresholds of temperature change for mass extinctions - by Haijun Song et al. (2021)
https://www.nature.com/articles/s41467-021-25019-2

• Co-extinctions annihilate planetary life during extreme environmental change - by Giovanni Strona and Corey Bradshaw (2018)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6233172

• When Will We Die?
https://arctic-news.blogspot.com/2019/06/when-will-we-die.html

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

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

Wednesday, January 19, 2022

The climatic effects of a nuclear winter on a warming Earth

by Andrew Glikson

Figure 1. “The Nuclear Winter” by Carl Sagan

The Cretaceous-Paleocene boundary (~66 million years-ago) asteroid impact, described in 1980 by Alvarez et al., caused enough dust and debris to cloud large parts of planet and result in the mass extinction of some 80% of all species of animals.

When Turco et al. (1983) and Carl Sagan (1983) warned the world about the climatic effects of a nuclear war, they pointed out that the amount of carbon stored in a large city was sufficient to release enough aerosols (smoke, soot and dust) to block sunlight over large regions, leading to a widespread failure of crops and thereby extensive starvation.

Current nuclear arsenals by the United States and Russia could inject 150 Teragram (Tg) (10⁹ kilogram) of soot from fires ignited by nuclear explosions into the upper troposphere and lower stratosphere (Coupe et al., 2019), lasting for a period of 10 years or longer, followed by a period of intense radioactive radiation over large areas. Even a “limited” nuclear war, such as between India and Pakistan, would release enough aerosols to affect large regions, killing millions or billions through starvation. As stated by Robock et al., 2007): “The casualties from the direct effects of blast, radioactivity, and fires resulting from the massive use of nuclear weapons by the superpowers would be so catastrophic … the ensuing nuclear winter would produce famine for billions of people far from the target zones”.

By 2021, with a global arsenal of ~13.000 nuclear warheads, 90 percent of which held by Russia and the US, regional conflicts such as in the Ukraine and Taiwan threaten to spill world-wide. As the clock of the atomic scientists is set at 100 seconds to doomsday, the rising probability of an intended or inadvertent nuclear war, in the background of rising global warming, indicate an hour of truth for the species―a choice between the defence of life on Earth and global suicide.

While the inhabitants of the planet are preoccupied with the 24 hours news cycle, media hype, superlatives, a deadly Virus, economic issues and sport games, the hair-trigger nuclear gun loaded by the powers to be, east and west, are threatening all life on Earth.

Figure 2. Robock et al. (2007): Global average surface air temperature change from the 5 Tg standard case (red) in the context of climate change over 125 years climate change (125 years NASA data). From Robock et al. (2007).

A release of 5Tg (Tera-gram) of black carbon is modelled to lower the average global temperature by about 1.5°C (Robock et al. 2007), although over the continents cooling is likely to be more abrupt.

Figure 3. Robock et al. (2007): Time variation of global average net surface shortwave radiation, surface air temperature, and precipitation changes for the 5 Tg standard case. The global average precipitation in the control case is 3.0 mm/day, so the changes in years 2-4 represent a 9% global average reduction in precipitation. The precipitation recovers faster than the temperature, but both lag the forcing. For comparison the global average net surface shortwave forcing from a model simulation of the 1991 Mt. Pinatubo eruption (Oman et al., 2005) is shown.

Inherent in nuclear war strategy is a “use them or lose them” approach, namely hitting the enemy’s air and missile launch pads before missiles can be launched, which amounts to a virtual guarantee many or most nuclear war heads are potentially used. With the estimated size of the global nuclear warheads inventory of many tens of thousands warheads (Figure 4) this guarantees a global catastrophe.

Figure 4. 2021 Estimated global nuclear warhead inventories

Such an extreme event would arrest global warming for a period of about 10 years or longer (Figures 2 and 3), possibly in part analogous to the consequences of a less abrupt flow of polar ice melt into the oceans, as modelled by Bronselaer et al. (2018) (Figure 5).

Figure 5. Model 2080–2100 meltwater-induced sea-air temperature anomalies relative to the standard RCP8.5 ensemble (Bronselaer et al., 2018), indicating marked cooling of parts of the southern oceans. Hatching indicates where the anomalies are not significant at the 95% level.

When Sagan and colleagues published their observations of a nuclear winter scenario as a warning to humanity, Sagan was painted as an “alarmist” by many, facing extensive criticism not just from pro-nuclear conservatives but also from scientists who resented him for leveraging his personal fame for advocating what some regarded as political views. A similar situation occurs nowadays with regard to the accelerating global warming and the nuclear threat, as confirmed by the warning by the Bulletin of the Atomic Scientists.

From the January 20, 2022 Bulletin of the Atomic Scientists news release:
While the past year offered glimmers of hope that humankind might reverse its march toward global catastrophe, the Doomsday Clock was set at just 100 seconds to midnight. The time is based on continuing and dangerous threats posed by nuclear weapons, climate change, disruptive technologies, and COVID-19. All of these factors were exacerbated by “a corrupted information ecosphere that undermines rational decision making.” The Doomsday Clock statement explains that the “decision does not, by any means, suggest that the international security situation has stabilized. On the contrary, the Clock remains the closest it has ever been to civilization-ending apocalypse because the world remains stuck in an extremely dangerous moment.”

Time is running out.

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, January 11, 2022

Accelerating global warming and amplifying feedbacks: The imperative of CO₂ drawdown

by Andrew Glikson

Satellite measurements indicate that 2021 was one of the warmest years on record, with the past seven years being the hottest period recorded globally (Met Office, January 10, 2022). Attempts at global emission reductions, lowered in part due to COVID-19 economic slow-down, appear to have little effect on atmospheric CO₂ rise, as indicated by the current rise of atmospheric carbon dioxide to record high levels of 420 ppm despite reduced emissions in 2020-2021 (Figures 1 and 2).

Figure 1. A. Mean global CO₂ levels from 800,000 years to the present (NASA).
B. Mean global temperature rise from 1850 to 2021 (Berkeley Earth).

As stated by CarbonBrief: “The year so far has been one of extremes, featuring record-shattering heatwaves, wildfires and flooding, as well as the warmest-ever northern-hemisphere summer – June, July and August – in the global land-surface record.”

Whereas climate negotiations mostly focus on possible reductions in emissions, the cumulative buildup of greenhouse gases is determining the future of the terrestrial climate. According to NASA “Once it’s (CO₂) added to the atmosphere, it hangs around, for a long time: between 300 to 1,000 years".

Other estimates are much longer. Because of the longevity of CO₂ and other greenhouses gases in the atmosphere, a decrease in carbon emissions, while essential, is not sufficient to reduce CO₂ levels in the atmosphere in time.

According to the IPCC “about 50% of a CO₂ increase will be removed from the atmosphere within 30 years, and a further 30% will be removed within a few centuries. The remaining 20% may stay in the atmosphere for many thousands of years”. According to the US EPA (Environmental Protection Agency) “Atmospheric lifetime: 50-200 years. No single lifetime can be defined for CO₂ because of the different rates of uptake by different removal processes”.

According to Solomon et al. (2009) and Eby et al. (2009) high levels of CO₂ on the scale of 10² to 10³ ppm would persist for millennia.

Global emission reductions, decreased in part due to COVID-19 economic slow-down, have little effect on the atmospheric CO₂ level, as indicated by the current trend of atmospheric carbon dioxide, at record high levels despite reduced emissions in 2020 (Figure 2). This suggests to a significant extent the current rise in atmospheric CO₂ arises from amplifying feedbacks from land and ocean.

Figure 2. A. Observed and forecast monthly and annual CO2 concentrations at Mauna Loa.
Observations from the Scripps CO2 program, forecasts from Met Office. Credit: Met Office.
B. Measured and forecast monthly CO2 concentrations at Mauna Loa Observatory, Hawaii.
Black line: measurements by the Scripps Institution of Oceanography, UC San Diego. Solid red line
with vertical uncertainty bars: forecast by the Met Office, including the revised forecast for 2020
issued in May 2020 accounting for reduced global emissions due to societal responses to Covid-19.
The forecast uncertainty estimate is ± 0.6 ppm. Dotted red line: original Met Office forecast for
2020 issued in January 2020, not accounting for Covid-related emissions reductions.
Horizontal dashed blue line: 417 ppm, a 50% increase above 278 ppm, the level in 1750-1800
from ice core records.

All taking place notwithstanding hollow promises made at COP26, a meeting noted for the near-absence of contributions by climate scientists.

In trying to avoid an exponential rise in greenhouse gases toward catastrophic levels, one option exists, namely urgent attempts at drawing down at least part of the CO₂ concentration of the atmosphere. The $trillions of dollars required, constituting the “Price of the Earth”, may not exceed the $trillion dollars military expenses spent by the world over the last 70 years, including nuclear missile fleets which constitute a separate threat for life on Earth, as warned by Albert Einstein: “The unleashed power of the atom has changed everything save our modes of thinking and we thus drift toward unparalleled catastrophe”.

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

Wednesday, January 5, 2022

Terrifying Arctic greenhouse gas levels continue

NOAA's September 2021 global mean methane reading is 1900.5 parts per billion (ppb), which is 15.8 ppb higher than the reading for September 2020. By comparison, NOAA's annual global mean methane increase for 2020 of 15.74 ppb was at the time the highest on record.

Keep in mind that this 1900.5 ppb reading is for September 2021; it now is January 2022. Furthermore, NOAA's data are for marine surface measurements; more methane tends to accumulate at higher altitudes, and especially at higher latitudes North, as also illustrated by the images further below.

Above, a combination image of methane averages between latitudes 60°S and 60°N (top) and annual growth rates for these data (bottom) through to 2021, from a Copernicus news release.

The image on the right shows the Copernicus data for methane growth with an added trend that ominously points at a growth rate for 2022 that could be more than 20%.

Keep in mind that these are data for the latitude range from 60°S and 60°N, whereas some very high methane concentrations are being recorded over the area within the Arctic Circle (66°30′ N).

Very high greenhouse gas levels continue to show up over the Arctic. The image below, created with a Copernicus forecast for January 4, 2022, 03 UTC, shows methane at 500 hPa.

The image further down below is a screenshot of a Copernicus forecast for January 5, 2022, 03 UTC, again showing methane at 500 hPa, but this time using a North Pole projection.

The darkest-brown color on the scale for 500 hPa on the Copernicus images (above and below) indicates methane concentrations of 1950 ppb and higher.

While the Copernicus images show well that such concentrations (of 1950 ppb and higher) dominate over the Arctic at 500 hPa, the scales used by Copernicus have upper limits of 2300 ppb (300 hPa), 2360 (500 hPa) and 2320 (total column) which could give the false impression that higher concentrations did not occur at higher altitudes.

Higher methane concentrations do actually occur at around 500 hPa, as the images on the right illustrate. Such high peaks are important as they could be caused by abrupt methane releases rising in plumes from the seafloor of the Arctic Ocean.

The N20 satellite image on the right that shows concentrations of up to 2585 ppb at 487.2 mb (equivalent to 487.2 hPa) on January 6, 2022.

Another recent example is the MetOp satellite peak reading on the right of 2854 ppb at 586 mb on January 9, 2022.

An earlier example is a MetOp satellite reading of up to 2861 ppb at 469 mb on December 31, 2021.

Further examples are readings of up to 2852 ppb at 506 mb and up to 3644 ppb at 367 mb on November 21, 2021, pm.

The image below is a screenshot of a Copernicus forecast for January 5, 2022, 03 UTC, this time showing methane at surface level and using a Eurasia projection. Note that the darkest-brown color on the scale for surface level indicates methane concentrations above 2160 parts per billion (ppb).

The image below is a forecast for January 9, 2022, 03 UTC, run January 9, 2022, 00 UTC. The scale for this image goes up to 24840 ppb. That doesn't necessarily mean that concentrations are forecast to be as high as that; Copernicus has simply fixed the top end of the scale for 850 hPa at 24840 ppb.

For its surface forecasts, Copernicus appears to use a combination of models and observations, with an emphasis on extrapolating from in situ measurements, which can ignore methane releases from locations where such in situ measurements are lacking, particularly over the Arctic Ocean. By contrast, the animation below of December 31, 2021 am, polar-orbiting MetOp satellite images, from an earlier post, shows the highest methane concentrations first emerging over water at higher latitudes North, rather than over land.

Clearly, some very high methane concentrations are showing up over the Arctic. The image below shows monthly average in situ methane measurements recorded at Barrow, Alaska, with high averages showing up for recent months.

Furthermore, carbon dioxide levels also continue to be very high at Barrow, Alaska, as illustrated by the image below, showing a recent daily average exceeding 430 ppm.

Locally, CO₂ concentration can be even higher. The image below shows a concentration of 440 ppm over the Arctic Ocean at the green circle, as the jet stream crosses the Arctic on January 19, 2022.

CO₂ concentration at Mauna Loa was 420.52 ppm on January 26, 2022. The annual peak for CO₂ is expected to occur about May 2022, so it will still go up a lot higher than this over the next few months.

Why again is this growth in methane so terrifying?

The danger is that these high concentrations of greenhouse gases over the Arctic will contribute to high temperature anomalies in the Arctic and result in further decline of the snow and ice cover and associated changes to the Jet Stream, causing abrupt methane releases from submarine sediments containing hydrates and chambers of free gas.

The MetOp-B satellite recorded a mean methane level of 1958 ppb on October 25, 2021 am at 295 mb, and when using a 1-year GWP of 200, this translates into 391.6 ppm CO₂e. Together with the above CO₂, that's 391.6 + 420.52 = 812.12 ppm CO₂e.

Now add an additional 5 Gt of methane from an abrupt eruption of the seafloor, which is only 10% of the 50 Gt that Natalia Shakhova et al. warned about long ago, while 50 Gt is in turn only a small fraction of all the methane contained in sediments in the Arctic. On its own, such an eruption of seafloor methane could raise the global mean methane concentration by almost 2000 ppb which, at a 1-year GWP of 200, would translate into 400 ppm CO₂.

So, that would abruptly cause the joint CO₂e of just two greenhouse gases, i.e. methane and CO₂, to cross the 1200 ppm clouds tipping point, triggering a further 8°C global temperature rise, due to the clouds feedback.

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

Links

• NOAA - globally averaged marine surface monthly mean methane data
https://gml.noaa.gov/webdata/ccgg/trends/ch4/ch4_mm_gl.txt

• NOAA - globally averaged marine surface annual mean methane growth rates

https://gml.noaa.gov/webdata/ccgg/trends/ch4/ch4_gr_gl.txt

• Copernicus news release

https://climate.copernicus.eu/sites/default/files/custom-uploads/Annual_summary_2021/C3S-CAMS%20annual%20temp%20data%20and%20CO2%202021_press%20release_final.pdf

• Terrifying Arctic methane levels