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

Edge of Extinction

Guy McPherson

Guy McPherson is convinced that humunity will go extinct soon. Guy estimates that it will happen in 5 to 20 years time.

In the video below, Guy discusses a chain of events causing several degrees warming within a few years time, including failure of the electric grid and subsequent fall in aerosols from fossil fuel burning that now mask warming, and failure to maintain nuclear power plants cooling, causing them to melt down.

These events will cause rapid warming that will accelerate loss of the snow and sea ice in the Arctic and cause massive methane releases from the seafloor of the Arctic Ocean, both adding even further warming.

Such massive warming will result in widespread crop failure and loss of habitat for humans over a timespan of up to 20 years, while events could all unfold in just 5 years time.

In the video below, Guy discusses that we are on the edge of extinction, episode 1.

Feedbacks   Professor Peter Wadhams on albedo changes in the Arctic Conclusion from a paper presented at the 2008 EGU conference, on background of a frame from a video interview by Nick Breeze with Natalia Shakhova.

In the video below, episode 2, Guy describes how large releases of methane from the seafloor of the Arctic Ocean alone could end civilization, as they will cause crop failure on the Northern Hemisphere and subsequent collapse of civilization. This will in turn cause failure of the electric grid, etc., as described above. So, whatever event comes first, it will trigger the other events, resulting in several degrees Celsius warming within years and loss of habitat for humans.

The image below highlights some of the complexities associated with the necessary cuts in emissions, including the impact of aerosols that mask the full wrath of global warming by half. In 2007, the IPCC described aerosols as a negative (cooling) force equal to between -0.5 and -2.5 W m-2. In 2009, Murphy et al suggested an aerosol forcing about -1.5 W m-2, reducing the net climate forcing of the past century by about half. In 2011, Hansen et al, based mainly on analysis of Earth's energy imbalance, derived an aerosol forcing -1.6 ± 0.3 W m-2. [source] As David Spratt points out, this equates to a cooling of about 1.2°C. In other words, abrupt ending of aerosols emissions would result in a temperature rise of about 1.2°C in a matter of weeks.

In the video below, Guy McPherson further discusses the impact of aerosols.

Below, 'Edge of Extinction', episode 3, published on 15 January, 2015, featuring Guy McPherson in a fine moment of comedy! Excerpt from his presentation at Butte College, November 20, 2014, Chico, California.

Below, 'Edge of Extinction', episode 4, published on 21 January, 2015, in which Guy comments on the State of the Union address of January 20, 2015.

Below, 'Edge of Extinction', episode 5, published on 27 Jan 2015, featuring an excerpt from Guy McPherson's interview on Global Research December 12, 2014 on the stages of grief. 

Follow Guy McPherson's European Trip March/April 2015. 

How Do We Act in the Face of Climate Chaos?

Guy McPherson

Guy R. McPherson is Professor Emeritus of Natural Resources
and Ecology & Evolutionary Biology at University of Arizona.
Below are some (slighly edited) extracts from a post at Guy
McPherson's website: summary and update on climate change.

The Warning

As described by the United Nations Advisory Group on Greenhouse Gases in 1990, temperature rise “beyond 1 degree C may elicit rapid, unpredictable and non-linear responses that could lead to extensive ecosystem damage”.

We’ve clearly triggered the types of positive feedbacks the United Nations warned about in 1990. Yet my colleagues and acquaintances think we can and will work our way out of this horrific mess with permaculture (which is not to denigrate permaculture, the principles of which are implemented at the mud hut). Reforestation doesn’t come close to overcoming combustion of fossil fuels, as pointed out in the 30 May 2013 issue of Nature Climate Change. Furthermore, forested ecosystems do not sequester additional carbon dioxide as it increases in the atmosphere, as disappointingly explained in the 6 August 2013 issue of New Phytologist.

Here’s the bottom line: On a planet 4 C hotter than baseline, all we can prepare for is human extinction (from Oliver Tickell’s 2008 synthesis in the Guardian).

John Davies concludes: “The world is probably at the start of a runaway Greenhouse Event which will end most human life on Earth before 2040.” He considers only atmospheric carbon dioxide concentration, not the many self-reinforcing feedback loops described below. 

Positive feedbacks

Positive feedbacks

Methane hydrates are bubbling out the Arctic Ocean (Science, March 2010). According to NASA’s CARVE project, these plumes were up to 150 kilometers across as of mid-July 2013. Whereas Malcolm Light’s 9 February 2012 forecast of extinction of all life on Earth by the middle of this century appears premature because his conclusion of exponential methane release during summer 2011 was based on data subsequently revised and smoothed by U.S. government agencies, subsequent information — most notably from NASA’s CARVE project — indicates the grave potential for catastrophic release of methane. Catastrophically rapid release of methane in the Arctic is further supported by Nafeez Ahmed’s thorough analysis in the 5 August 2013 issue of the Guardian as well as Natalia Shakhova’s 29 July 2013 interview with Nick Breeze (note the look of abject despair at the eight-minute mark).

Warm Atlantic water is defrosting the Arctic as it shoots through the Fram Strait (Science, January 2011).

Siberian methane vents have increased in size from less than a meter across in the summer of 2010 to about a kilometer across in 2011 (Tellus, February 2011)

Drought in the Amazon triggered the release of more carbon than the United States in 2010 (Science, February 2011). In addition, ongoing deforestation in the region is driving declines in precipitation at a rate much faster than long thought, as reported in the 19 July 2013 issue of Geophysical Research Letters.

Peat in the world’s boreal forests is decomposing at an astonishing rate (Nature Communications, November 2011)

Invasion of tall shrubs warms the soil, hence destabilizes the permafrost (Environmental Research Letters, March 2012)

Greenland ice is darkening (The Cryosphere, June 2012)

Methane is being released from the Antarctic, too (Nature, August 2012). According to a paper in the 24 July 2013 issue of Scientific Reports, melt rate in the Antarctic has caught up to the Arctic.

Russian forest and bog fires are growing (NASA, August 2012), a phenomenon consequently apparent throughout the northern hemisphere (Nature Communications, July 2013). The New York Times reports hotter, drier conditions leading to huge fires in western North America as the “new normal” in their 1 July 2013 issue. A paper in the 22 July 2013 issue of the Proceedings of the National Academy of Sciences indicates boreal forests are burning at a rate exceeding that of the last 10,000 years.

Cracking of glaciers accelerates in the presence of increased carbon dioxide(Journal of Physics D: Applied Physics, October 2012)

The Beaufort Gyre apparently has reversed course (U.S. National Snow and Ice Data Center, October 2012)

Exposure to sunlight increases bacterial conversion of exposed soil carbon, thus accelerating thawing of the permafrost (Proceedings of the National Academy of Sciences, February 2013)

The microbes have joined the party, too, according to a paper in the 23 February 2013 issue of New Scientist

Summer ice melt in Antarctica is at its highest level in a thousand years: Summer ice in the Antarctic is melting 10 times quicker than it was 600 years ago, with the most rapid melt occurring in the last 50 years (Nature Geoscience, April 2013). Although scientists have long expressed concern about the instability of the West Atlantic Ice Sheet (WAIS), a research paper published in the 28 August 2013 of Nature indicates the East Atlantic Ice Sheet (EAIS) has undergone rapid changes in the past five decades. The latter is the world’s largest ice sheet and was previously thought to be at little risk from climate change. But it has undergone rapid changes in the past five decades, signaling a potential threat to global sea levels. The EAIS holds enough water to raise sea levels more than 50 meters.

Floods in Canada are sending pulses of silty water out through the Mackenzie Delta and into the Beaufort Sea, thus painting brown a wide section of the Arctic Ocean near the Mackenzie Delta brown (NASA, June 2013)

Surface meltwater draining through cracks in an ice sheet can warm the sheet from the inside, softening the ice and letting it flow faster, according to a study accepted for publication in the Journal of Geophysical Research: Earth Surface (July 2013). It appears a Heinrich Event has been triggered in Greenland. Consider the description of such an event as provided by Robert Scribbler on 8 August 2013:

In a Heinrich Event, the melt forces eventually reach a tipping point. The warmer water has greatly softened the ice sheet. Floods of water flow out beneath the ice. Ice ponds grow into great lakes that may spill out both over top of the ice and underneath it. Large ice damns (sic) may or may not start to form. All through this time ice motion and melt is accelerating. Finally, a major tipping point is reached and in a single large event or ongoing series of such events, a massive surge of water and ice flush outward as the ice sheet enters an entirely chaotic state. Tsunamis of melt water rush out bearing their vast floatillas (sic) of ice burgs (sic), greatly contributing to sea level rise. And that’s when the weather really starts to get nasty. In the case of Greenland, the firing line for such events is the entire North Atlantic and, ultimately the Northern Hemisphere.

Breakdown of the thermohaline conveyor belt is happening in the Antarctic as well as the Arctic, thus leading to melting of Antarctic permafrost (Scientific Reports, July 2013)

Loss of Arctic sea ice is reducing the temperature gradient between the poles and the equator, thus causing the jet stream to slow and meander. One result is the creation of weather blocks such as the recent very high temperatures in Alaska. As aresult, boreal peat dries and catches fire like a coal seam. The resulting soot enters the atmosphere to fall again, coating the ice surface elsewhere, thus reducing albedo and hastening the melting of ice. Each of these individual phenomena has been reported, albeit rarely, but to my knowledge the dots have not been connected beyond this space. The inability or unwillingness of the media to connect two dots is not surprising, and has been routinely reported (recently including here with respect to climate change and wildfires) (July 2013)

Arctic ice is growing darker, hence less reflective (Nature Climate Change, August 2013)

Extreme weather events drive climate change, as reported in the 15 August 2013 issue of Nature (Nature, August 2013)

Ocean acidification leads to release of less dimethyl sulphide (DMS) by plankton. DMS shields Earth from radiation. (Nature Climate Change, online 25 August 2013)

Sea-level rise causes slope collapse, tsunamis, and release of methane, as reported in the September 2013 issue of Geology

Rising ocean temperatures will upset natural cycles of carbon dioxide, nitrogen and phosphorus, hence reducing plankton (Nature Climate Change, September 2013)

Earthquakes trigger methane release, and consequent warming of the planet triggers earthquakes, as reported by Sam Carana at Arctic-news (October 2013)

Arctic drilling was fast-tracked by the Obama administration during the summer of 2012

Supertankers are taking advantage of the slushy Arctic, demonstrating that every catastrophe represents a business opportunity, as pointed out by Professor of journalism Michael I. Niman and picked up by Truthout (ArtVoice, September 2013)

As nearly as I can distinguish, only the latter feedback process is reversible at a temporal scale relevant to our species. Once you pull the tab on the can of beer, there’s no keeping the carbon dioxide from bubbling up and out. These feedbacks are not additive, they are multiplicative. Now that we’ve entered the era of expensive oil, I can’t imagine we’ll voluntarily terminate the process of drilling for oil and gas in the Arctic (or anywhere else). Nor will we willingly forgo a few dollars by failing to take advantage of the long-sought Northwest Passage.

Robin Westenra provides an assessment of these positive feedbacks at Seemorerocks on 14 July 2013. It’s worth a look.

Where we’re going

An increasing number of scientists agree that warming of 4 to 6 C causes a dead planet. And, they go on to say, we’ll be there by 2060. 

Earth-system scientist Clive Hamilton concludes in his April 2013 book Earthmasters that “without [atmospheric sulphates associated with industrial activity] … Earth would be an extra 1.1 C warmer.” In other words, collapse takes us directly to 2 C within a matter of weeks. 

Several other academic scientists have concluded, in the refereed journal literature no less, that the 2 C mark is essentially impossible (for example, see the review paper by Mark New and colleagues published in the 29 November 2010 issue of the Philosophical Transactions of the Royal Society A). 

The German Institute for International and Security Affairs concluded 2 June 2013 that a 2 C rise in global-average temperature is no longer feasible (and Spiegel agrees, finally, in their 7 June 2013 issue), while the ultra-conservative International Energy Agency concludes that, “coal will nearly overtake oil as the dominant energy source by 2017 … without a major shift away from coal, average global temperatures could rise by 6 degrees Celsius by 2050, leading to devastating climate change.” 

Image from: The two epochs of Marcott, by Jos Hagelaars

At the 11:20 mark of this video, climate scientist Paul Beckwith indicates Earth could warm by 6 C within a decade. 

If you think his view is extreme, consider: 

1. the 5 C rise in global-average temperature 55 million years ago during a span of 13 years (reported in the 1 October 2013 issue of Proceedings of the National Academy of Sciences); and also 
2. the reconstruction of regional and global temperature for the past 11,300 years published in Science in March 2013. One result is shown in the above figure.

How Do We Act in the Face of Climate Chaos?

Below is a video of a recent presentation by Guy McPherson. 

Presentation by Guy McPherson in Boulder, Colorado on October 16, 2013.

Below are some extracts from the video, again slightly edited.

Malcolm Light in 2012 concluded, based on data from NOAA and NASA, that methane release had gone exponential and was leading to the demise of all life on Earth, not just human extinction, by the middle of the century.

So 3.5 C to 4 C is almost certainly a death sentence for all human beings on the planet, not because it'll be a warmer planet, but because the warming of the planet will remove all habitat for human beings. Ultimately we're human animals like other animals, we need habitat to survive.

Changes we see in three or four decades happen as a result of what we do today. There's a huge lag between our actions today in the consequences down the road in terms of the Earth's planetary systems.

Without plankton in the ocean, there goes roughly half the global food supply. The ability to lose land plants is growing rapidly and there goes the other half for the food supply for human beings. If we have up to 5 C by 2050, that'll certainly do the trick.

Why is this happening? It's civilization that drove us into population overshoot. We cannot go back anymore since 1939, since we invented nuclear armageddon. There's no going back. If we ceased the set of living arrangements at this point, the world's 400 or so nuclear power plants melt down catastrophically and we're all dead in a month. We cannot terminate industrial civilization until we decommission all nuclear power plants. It takes at least 20 years to decommission a nuclear power plant.

The bad news is that means that the world's four hundred or so nuclear power plants meltdown catastrophically in a short period of time. Fukushima represent a major threat to humanity. If they fail in moving the spent fuel rods next month, according to nuclear researcher Christina Consola, if one of those MOX fuel rods is exposed to the air, one of the 1565, it will kill 2.89 billion people on the planet in a matter of weeks, so nuclear catastrophe is right there on the horizon. 

People ask me: Why are you presenting this horrible information?

Action is the antidote to despair even if the action is hopeless. When a medical doctor knows that somebody has cancer, it's malpractice if they don't tell that. So I'm doing that. I think Bill McKibben and James Hansen and a whole bunch of climate scientists are guilty of malpractice. Because they know what I know. Almost every politician in the country knows what I know. All the leaders of the big banks know what I know. And they're lying to us.

I'm just presenting the information from other scientists here. I'm trying to the widest extent possible not to infuse my opinion in the situation. It's John Davies who on September 20, 2013, taking into account only carbon dioxide, says there will be few people left on the planet by 2040. It's Malcolm Light, writing in February 2012, who assesses the methane situation. And so on.

Yes, I agree with them, and that agreement is illustrated by me showing you that information.

I promote resistance against this omnicidal culture, not in the hope that it will save our species, but in the hope that it will save other species. Because as E.O. Wilson, biologist at Harvard, points out, it only takes 10 million years after a great extinction event, before you have a blossoming full rich planet again. That's what we're working toward. We're saving habitat for other species at this point.