Scientific Shocker: Earth's Greatest Extinction Was Caused by Methane
April 6, 2014
Dan Dry/Handout/Reuters & The Arctic Methane Emergency Group & Jon Queally / Common Dreams
Methane-spewing microbes -- not volcanoes or asteroids -- triggered a global catastrophe 252 million years ago that wiped out nearly all life on Earth, according to a new theory put forward by scientists.
Methane-spewing Microbes Led to Worst Extinction on Earth, New Theory Says
(April 1, 2014) -- Methane-spewing microbes -- not volcanoes or asteroids -- triggered a global catastrophe 252 million years ago that wiped out nearly all life on Earth, according to a new theory put forward by scientists.
The mass extinction represented the worst of five such catastrophic events thought to have occurred during the history of the planet, with more than 90 percent of marine species and 70 percent of land vertebrate species wiped out. The scale of this extinction dwarfs the calamity that doomed the dinosaurs 65 million years ago, thought to have been triggered by a six-mile-wide asteroid smacking the planet.
Microbes known as Methanosarcina multiplied on a massive and sudden scale in the ocean, spewing methane into the atmosphere and causing dramatic changes in the chemistry of the seas and the Earth's climate, according to the theory, put forth Monday by scientists at the Massachusetts Institute of Technology and colleagues in China.
The resulting burst in methane produced effects similar to those predicted by current models of global climate change: a sudden, extreme rise in temperatures, combined with acidification of the oceans.
"I would say that the end-Permian extinction is the closest animal life has ever come to being totally wiped out, and it may have come pretty close," said MIT biologist Greg Fournier, one of the researchers. "Many, if not most, of the surviving groups of organisms barely hung on, with only a few species making it through, many probably by chance," he added.
On land, most species were killed off, except for a handful of lineages, including ancestors of modern mammals.
Methanosarcina grew in a frenzy in the seas, disgorging huge quantities of methane into the atmosphere, they said. This dramatically heated up the climate and fundamentally altered the chemistry of the oceans by driving up acidity, causing unlivable conditions for many species, they added.
Asteroids and volcanic eruptions have been blamed for the mass extinction, but researchers instead pointed to microbes.
Geochemical evidence showed an exponential increase of carbon dioxide in the oceans at the time of the Permian extinction. At the same time, genetic evidence shows a change in Methanosarcina that allowed it to produce methane from an accumulation of carbon dioxide in the water.
Finally, sediments show a sudden increase in the amount of nickel deposited at the time. Though volcanic eruptions on their own could not explain why the die-off happened so quickly, they probably released extra nickel into the environment, which fed the microbes, said Fournier.
"A rapid initial injection of carbon dioxide from a volcano would be followed by a gradual decrease," he said. "Instead, we see the opposite -- a rapid, continuing increase. That suggests a microbial expansion."
Microbes can increase carbon production exponentially, which might explain the speed and scale of the extinction, he said.
The research -- funded by NASA, the National Science Foundation, the Natural Science Foundation of China and the National Basic Research Program of China -- appears in the journal Proceedings of the National Academy of Sciences.
The first dinosaurs appeared 20 million years after the Permian extinction.
"Land vertebrates took as long as 30 million years to reach the same levels of biodiversity as before the extinction, and afterward life in the oceans and on land was radically changed, dominated by very different groups of animals," Fournier said.
Al Jazeera and wire services
"Countering Strong Positive Feedbacks in the Arctic
To Avoid Catastrophic Climate Change"
Arctic Methane Emergency Group Chairman John Nissen /
Presentation given at the "Davos Atmosphere and Cryosphere Assembly
( July 12, 2013) --
1. Intervention Is Sensible
This conference has underlined the extent of mankind's inadvertent interference with the Earth System, besides CO2, both to produce positive forcing (i.e. heating) and negative forcing (i.e. cooling) in different places and at different times.
The degree of cooling is shown by the fact that global surface temperature has not changed very much since 1998. But there are natural factors at play. Here, the negative forcing has been mainly provided by a combination of SO2 from volcanoes, and SO2 from industrial emissions. There is also a suggestion that aircraft contrails could be having a quantitatively similar cooling effect.
This gives hope that with deliberate interference, we can produce the necessary countermeasures by a combination of deliberate cooling, enhancement of natural cooling, and reduction of both manmade and natural forcing/warming agents.
This has to be done carefully, with each ingredient produced in the right quantity, right place and right time to produce the required overall effect: ultimately to restore the Earth System to a state where it can maintain a temperature and climate conducive to agriculture and aquaculture, and allow our civilisation to flourish.
2. Breaking the Vicious Cycle
In the Arctic, a vicious cycle of warming and melting may have started in the 80s when the masking effect of SO2 was reduced, producing a net warming of currents flowing from Atlantic and Pacific into the Arctic. This reduction was sufficient to start the cycle, but very soon the cycle became self¬-sustaining, such that we are now at a point that any reduction of greenhouse gases would have negligible effect on the rapid decline in sea ice.
We have to find a way of introducing sufficient cooling power into the Arctic to break the cycle.
Looking at the albedo calculation, Hudson has 0.1 W/m2 in 2007, mounting to 0.3 W/m2 when sea ice goes at the end of summer, mounting to 0.7 W/m2 when sea ice is gone throughout the year. He says there is 90% cloud cover in summer ¬ so I wonder whether the cloud LWR positive forcing effect is countering its SWR negative forcing effect.
Some of the extra heat each year is going into melting ice, but much is going into warming the Arctic Ocean water -- to a considerable depth, because of the churning/mixing action of storms. Only a small amount of net heat is being carried away from the Arctic by atmospheric heat transport, though ultimately there will be a global warming effect. The heat added to the Arctic Ocean accumulates during the summer, producing further melting and a greater quantity of heat being added the next summer.
If the sums are right, we should see an exponential trend in sea ice volume decline -- and we do. There has been no other explanation for the observed exponential decline, that I know of Arctic Methane Emergency Group (AMEG) Presentation given by Chairman, John Nissen at the "Davos Atmosphere and Cryosphere Assembly DACA-13", July 12, 2013
The reduction in snow cover, most marked in June, has produced about as much extra heat per year from the albedo flip effect. Some of this extra heat goes into the ground and melting permafrost, but much goes straight into the atmosphere, contributing to the general warming of the Arctic. Thus there is a loose coupling between the vicious cycle of warming and retreat of sea ice with the cycle of warming and retreat of snow cover.
Peter Wadhams calculated that the warming effect by 2012 was roughly equivalent to forcing of 50 ppm of CO2 or around 0.8 W/m2. It was as if 50 years of anthropogenic CO2 emissions had been added to the atmosphere. As the sea ice retreats, it is equivalent to adding even more CO2. By the time the sea ice is gone at end summer, and snow has retreated similarly, the heating will be equivalent to 100 years of CO2 emissions. Cooling the Arctic should deserve a lot of carbon credit!
The work by Stephen Hudson (AGU, 2011) suggests that Wadham's calculation is on the pessimistic side, especially because of a high percentage of cloud cover in high summer, at the peak of the insolation. But Hudson's calculation only takes account of sea ice albedo loss. If you double up on his end¬summer¬ice¬free case of 0.3 W/m2, you get 0.6 W/m2.
Suppose we consider the loss of 2% of the planet's area or 10 million square kilometres of sea ice reflecting power, as it is replaced by sea. The albedo change is from fresh snow 0.85 to open water 0.10, or 0.75. The peak insolation is 400 W/m2, averaged over the year gives approximately one third.
If cloud cover halves this, we get a forcing of 0.75 * 400 / 3 /2 = 50 W/m2. Averaged over the planet, it is 1 W/m2. This could be doubled by including the snow retreat giving 2 W/m2 globally, which, when multiplied by the area of the planet, gives you one petawatt.
Thus we are now talking of requiring up to a total of 1 petawatt cooling power to be directed into the Arctic to start getting the snow and sea ice back, if most of it is allowed to go. The critical factor is the cloud cover. If we can make the clouds last longer or make them more reflective in the summer, we can have a big effect on snow and sea ice albedo loss. Thus cloud brightening and preservation techniques can have an important role in the Arctic.
On the other hand, if we can reduce them in late autumn and winter, we can allow more outgoing thermal radiation ¬ long wave radiation (LWR). So we could consider cloud seeding techniques with most of the snow falling into the sea. However, if much snow falls on sea ice, it could have an undesirable insulation effect, such as to dampen the freezing of water on the underside of the floating ice.
The best time for a lot of snow is at the end of winter and early spring, so that the cold is locked in by the snow's insulating effect, and albedo is enhanced as the sun rises in the sky.
Arctic air temperature, which has to be below freezing for forming sea ice, is much dependent on the cooling by convection from the planet surface. As the Arctic Ocean becomes sea ice free, the air temperature will rise above freezing, drawing in cold air from the continents. So it is critical that, at end summer, the continental land surface can cool quickly. It will be important also to prevent a churning of the ocean water and keep the surface water relatively fresh and conducive to freezing.
Physical methods can be deployed to produce or encourage the formation of thick ice, mimicking the tough¬to¬melt multi¬year ice, which has all but disappeared in the Arctic. Ice can be piled up or it can be thickened by spraying water on the surface. In the late winter or early spring, the thicker ice can be insulated by spraying snow or seeding clouds to produce snow.
There are physical methods which can also be used for strengthening the ice and preventing it breaking up in the spring. The melt rate increases dramatically once the sea ice is less than half a metre thick and subjected to breaking up from wave action, followed by wind dispersion. Much ice disappears each year through the Fram Strait and quickly melts away.
One technique which can be considered is to add wood chippings or similar material to ice to form what is known as pykrete ¬ from its inventor Pyke and its concrete¬like properties. For example, a long curved floating barrage of pykrete could be used to prevent flow of broken ice between islands. Pykrete could also be used to dampen wave action and allow sea ice formation more readily in the autumn and early winter. There could be many other applications.
3. Dealing with the Methane
We have to consider methane from the Arctic seabed, escaping from hydrate (or 'clathrate') deposits or from bubbles in sediment, or from permafrost decomposition, or from free methane beneath the heavily perforated permafrost. It seems that there is a non¬linear increase in methane to such a point that a general cooling of the seabed is required. We may require more specific measures than a general cooling of the Arctic to prevent an escalation of methane emissions.
There is a danger that these emissions could reach a point when they cause some kind of thermal feedback to produce more methane. There is also a danger of instability in the structures holding the methane, which could become destabilised, e.g. by submarine slump or earthquake. There is over a thousand gigatonnes of methane trapped under the ocean, for release if the permafrost thaws.
Some researchers are concerned that a pulse of 5 gigatonnes of methane, suddenly or over a few years, would double the atmospheric burden of methane, resulting in triggering methane feedback and even thermal runaway--the so¬called clathrate gun effect--which may have caused previous extinction events in the Earth's history.
We also have to consider methane from terrestrial permafrost, which contains enough carbon for tripling the carbon content of the atmosphere. Some of the permafrost carbon will be vegetation decaying to produce CO2. However much is under water, in thermokast lakes and ponds, such that it decomposes to produce methane, seen bubbling up and getting trapped under the ice in winter.
Fortunately there are good biological approaches to suppressing methane in these conditions, especially using diatoms. Diatoms photosynthesise, absorbing carbon dioxide and producing oxygen. They are foodstuff for the methanothrophs ¬ methane digesting organisms. The water is purified and a food chain can be started, e.g. to allow fish farming.
4. Food Security
There is mounting evidence that/ the warming of the Arctic relative to the tropics is resulting in a weakening of the jet stream, causing it to meander and get stuck in so¬called blocking patterns. This is resulting in an increase in climate extremes, a reduction of food productivity, an increase in the food price index and an increase in unrest, especially when already a billion people are at near-starvation level.
This has implications on food security for even the richest nations. Farmers rely on reasonably predictable weather, and this predictability is vanishing because the jet stream gets stuck in different places at unpredictable times. The warming of the Arctic is non¬linear, currently at over a degree per decade -- a rate which could double within a few years.
This non-linearity is reflected in the global food price index, which has sharply increased since 2007, and is now at the crisis level of 210. Last year a prediction was made by Complex Systems Institute that there would be riots this year, because of the trend in this index towards the crisis level. They were right!
Thus there is a great deal that can be done. We are facing a precipitous decline in sea ice, which is having non¬linear repercussions. Only by reacting very quickly do we have a good chance to break the sea ice cycle and prevent irreversible consequences.
What we need is for the international community, especially of nations around the Arctic, to recognise this situation as an opportunity for collaboration on behalf of all nations, to cool the Arctic, save the sea ice and suppress methane. There can be direct local benefits, especially in methane suppression, to smooth the political way forward.
Arctic Methane "Burp":
A Climate Catastrophe with $60 Trillion Pricetag
Jon Queally / Common Dreams
(July 24, 2013) -- Warning that a dramatic "burp" or "pulse" of methane from beneath the fragile permafrost of the Arctic caused by continued global warming would set off a "climate catastrophe," a new study says that the continued melting is also an economic "time bomb" that could cost the global economy $60 trillion.
Billions upon billions of tons of methane remain stored in the permafrost throughout the Arctic regions, but specific concern has been placed on the enormous reserves that sit locked beneath the East Siberian Arctic Shelf. Scientists have repeatedly warned that if these deposits -- many frozen in the form of methane hydrates -- were released, they would trigger massive feedback loops and dramatically increase the rate of global warming.
The new study confirms these established fears, but also looks at the potential social and economic costs that would follow.
Though the corporate scavengers of the fossil fuel and mining companies are drooling over the prospects of a melting arctic in order to exploit previously inaccessible reserves of mineral and energy resources, the climate researchers say both the planetary and economic impacts should be taken extremely seriously.
The report's authors say that global financial and political leaders of the world continue to avoid the warnings of scientists when it comes to the dangers posed by the melting arctic.
As the Guardian's John Vidal reports:
Governments and industry have expected the widespread warming of the Arctic region in the past 20 years to be an economic boon, allowing the exploitation of new gas and oilfields and enabling shipping to travel faster between Europe and Asia. But the release of a single giant "pulse" of methane from thawing Arctic permafrost beneath the East Siberian sea "could come with a $60tn [£39tn] global price tag", according to the researchers who have for the first time quantified the effects on the global economy.
Even the slow emission of a much smaller proportion of the vast quantities of methane locked up in the Arctic permafrost and offshore waters could trigger catastrophic climate change and "steep" economic losses, they say.
"The global impact of a warming Arctic is an economic time bomb," said Gail Whiteman, a climate policy analyst at Erasmus University in Rotterdam and one of the authors of the report.
"The imminent disappearance of the summer sea ice in the Arctic will have enormous implications for both the acceleration of climate change, and the release of methane from off-shore waters which are now able to warm up in the summer," added Cambridge University's Peter Wadhams, another co-author.
As Vidal notes:
The Arctic sea ice, which largely melts and reforms each year, is declining at an unprecedented rate. In 2013, it collapsed to under 3.5m sqkm by mid September, just 40% of its usual extent in the 1970s. Because the ice is also losing its thickness, some scientists expect the Arctic ocean to be largely free of summer ice by 2020.
The growing fear is that as the ice retreats, the warming of the sea water will allow offshore permafrost to release ever greater quantities of methane. A giant reservoir of the greenhouse gas, in the form of gas hydrates on the East Siberian Arctic Shelf (ESAS), could be emitted, either slowly over 50 years or catastrophically fast over a shorter time frame, say the researchers.
A "massive methane boost," explained Wadhams, "will have major implications for global economies and societies. Much of those costs would be borne by developing countries in the form of extreme weather, flooding and impacts on health and agricultural production."
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