The perp in the greatest mass extinction on earth? Methane
by Gaius Publius - AmericaBlog
In the past, when I’ve written about climate and mass extinctions, I generally single out two of them — the one 65 million years ago that ended the dinosaur era, and the one about 250 million years ago that killed off almost everything then alive and made room for the dinosaurs to develop.The dinosaur-killing extinction is called the “Cretaceous–Paleogene (K–Pg) extinction event” since it occurred between the Cretaceous Period and the Paleogene Period. The earlier extinction, also called the “Great Dying,” is the “Permian–Triassic (P–Tr) extinction event” and occurred between those two geological periods.
But starting from the first explosion of life on earth, some 540 million years ago, all geological periods are grouped into just three “eras” — the era of Old Life (Paleozoic Era), the era of Middle Life (Mesozoic Era, or the age of dinosaurs), and the era of New Life (Cenozoic Era, or the age of mammals and man).
The Paleozoic Era lasted over 290 million years. The Mesozoic Era lasted 185 million years. We’re in the Cenozoic Era now, and it’s lasted 65 million years.
Just three major divisions since life first exploded. And guess what divides these eras? The two mass extinctions I mentioned above. Here’s what that looks like in one handy chart:
Mass Extinctions since the Cambrian Period (about 540 million years ago)
So yes, mass extinctions — certainly mass extinctions of this size — matter. As I argued here and here, we may not using our little climate problem just to exit the Holocene (our current 12,000-year geological division). We may be exiting the entire Cenozoic Era. Now that’s a world-historical event.
The Great Dying was probably caused by atmospheric methane
So the first part of today’s piece to keep in mind is the major geological divisions. And make no mistake, the Great Dying was a great dying, the mother of all great dyings (my emphasis everywhere):
It is the Earth’s most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct. It is the only known mass extinction of insects. Some 57% of all families and 83% of all genera became extinct. Because so much biodiversity was lost, the recovery of life on Earth took significantly longer than after any other extinction event, possibly up to 10 million years. [Other sources say 30 million years.]
Now the second part of this discussion. People have been puzzled about the cause for a long time, and how it managed to be so … effective. Turns out that researchers at MIT may have found the answer — atmospheric methane. It’s the only explanation that fits the facts, and there’s much evidence to support it. Given the factual data that’s been assembled about the event, all of the other, previously-thought-plausible explanations have to be dismissed. Not one of the others could explain the combination of facts now known.
Let’s look at this from two sources, MIT and a separate write-up of their research. The MIT publication is informative, but the other is more clear for the lay reader. First, from the MIT news office:
Methane-producing microbes may be responsible for the largest mass extinction in Earth’s history
Evidence left at the crime scene is abundant and global: Fossil remains show that sometime around 252 million years ago, about 90 percent of all species on Earth were suddenly wiped out — by far the largest of this planet’s five known mass extinctions. But pinpointing the culprit has been difficult, and controversial.
Now, a team of MIT researchers may have found enough evidence to convict the guilty parties — but you’ll need a microscope to see the killers.
The perpetrators, this new work suggests, were not asteroids, volcanoes, or raging coal fires, all of which have been implicated previously. Rather, they were a form of microbes — specifically, methane-producing archaea called Methanosarcina — that suddenly bloomed explosively in the oceans, spewing prodigious amounts of methane into the atmosphere and dramatically changing the climate and the chemistry of the oceans.
Volcanoes are not entirely off the hook, according to this new scenario; they have simply been demoted to accessories to the crime. The reason for the sudden, explosive growth of the microbes, new evidence shows, may have been their novel ability to use a rich source of organic carbon, aided by a sudden influx of a nutrient required for their growth: the element nickel, emitted by massive volcanism at just that time.
The new solution to this mystery is published this week in the Proceedings of the National Academy of Science by MIT professor of geophysics Daniel Rothman, postdoc Gregory Fournier, and five other researchers at MIT and in China.
Now William Costolo at the Guardian Liberty Voice:
"The ocean swarm of micro-organisms was the byproduct of volcanic eruptions which threw off the substance nickel. The nickel from the volcanoes provided the metabolic fuel necessary for the bloom to occur. Scientists previously suspected that the volcano eruptions themselves caused the horrific killing, but the MIT researchers determined that the volcanoes alone would not have created enough atmospheric carbon dioxide to cause the mass extinction. The carbon dioxide must have come from another source.
"Further research indicated to the scientists that the source of the carbon dioxide was derived from a biological source. The carbon dioxide levels would have receded faster if derived only from the volcanoes. The rich source of nickel available from the volcanos was just the right fuel for the tiny methane producing killing machines to consume the carbon in the ocean floors and proliferate in rapid fashion.
"The analysis of genome material provided the necessary clues to the researchers. The Methanosarcina acquired a genetic trait from another microscopic organism which allowed them to quickly produce the poison gas under the right conditions. The vast store of carbon in the oceans together with the volcanic nickel provided the perfect storm of material required for a gigantic methane plume. The tiny organisms followed their genetic programming to reproduce quickly and throw off a massive amount of poison gas."
Except for his use of the term “poison gas” (living things weren’t “poisoned”), this is a clear explanation of the relationship between the massive volcanoes, the nickel, the microbes, and the methane. The killing happened in relatively short order, driven by the massive volcanoes.
The mass kill off, known as the Permian extinction, had its roots in the volcanoes of the Siberian Traps. The lava flows were so large they would have covered a land area larger than the United States. The atmosphere remained poisoned for over 100,000 years. The earth did not regenerate diverse life for another 30,000,000 years. The length of time the atmosphere remained poisoned was a clue to the researchers that the volcanoes alone could not have caused the killing catastrophe.
Why does methane have such a powerful effect? Read on.
Methane is far more powerful than CO2 at trapping heat
Why does methane’s greenhouse effect last so long? Partly because atmospheric methane degrades to CO2 by a fairly simple formula:
CH4 + 2 O2 → CO2 + 2 H2O
So while methane itself produces its own huge greenhouse gas effects (see below for the relative scale), it then disappears and leaves longer-lived CO2 in its place to do further greenhouse damage. CO2 doesn’t break down; it has to be extracted by some process, such as plant activity, dissolving into the ocean, and so on.
Atmospheric methane in sufficient quantity is a real problem, greenhouse-wise. The combined effect of the methane bomb and the resulting CO2 is what the MIT researchers say accounts for both the scale of the Great Dying and the 30-million-year recovery period. To give a sense of relative effects of these two greenhouse gases:
While more than half of the CO2 emitted is removed from the atmosphere within a century, some fraction (about 20%) of emitted CO2 remains in the atmosphere for many thousands of years.
In contrast, methane is more powerful, but shorter lived in the atmosphere:
Methane has an atmospheric lifetime of 12 ± 3 years and a GWP [global warming potential] of 72 over 20 years, 25 over 100 years and 7.6 over 500 years. The decrease in GWP at longer times is because methane is degraded to water and CO2 through chemical reactions in the atmosphere.
In all cases, the GWP number is relative to CO2. That is, CO2 is artifically assigned a GWP of “1″ and the GWP of other greenhouse gases is either a multiple or a fraction of that.
It gets worse. (1) That 20-year methane GWP number is likely low. This site says that the GWP of methane could be 10–40% low when indirect interactions are taken into account. I’ve seen estimates of methane’s 20-year greenhouse effect as high as 100 times that of CO2. And (2) that’s the 20-year effect. Methane lasts for 12 years on average. What do you think its effect is in the first 5–10 years, as a global warming accelerator?
Kind of explains the Great Dying, yes? Boom, the methane bomb goes off, and everything changes.
We’re melting a methane bomb in the Arctic
Which brings us to the fourth part of this discussion. So why do we care? Because we’re sitting on a “methane bomb” in the Arctic region — frozen, sequestered methane locked into the permafrost both on land and in the ocean, and climate change (global warming) is releasing it. NOAA (my emphasis):
[Methane hydrates] have also been proposed as major agents of climate change. Methane is a powerful greenhouse gas, ten times more effective at trapping heat than carbon dioxide. But the volume of this gas now in the atmosphere pales next to that currently sequestered in hydrates, estimated at ten thousand billion tons (about 3,000 times the amount of methane as the atmosphere).
Let that sink in. The methane in the permafrost is 3000 times the amount of methane already in the atmosphere. And don’t let that “ten times as effective at trapping heat” fool you. That’s the average over 100 years. Methane only lasts about 12 years before it’s gone. When it starts out, before it breaks down, it’s likely a hundred times more effective than CO2. Or as the NOAA site above puts it:
A methane build-up will greatly enhance the intensified greenhouse effect that is driving global warming, and could cause the temperature to rise even higher, and to rise quickly.
As we reported earlier, this gives a sense of the scale of the methane melt. Coming off the floor of the ocean, methane reverts to a gas and forms “plumes” — literally torch-shaped structures created by water pressure — that rise to the surface. These plumes have been observed and measured for a fair number of years, and their recent growth in size and number is astonishing:
Vast methane ‘plumes’ seen in Arctic ocean as sea ice retreats
Dramatic and unprecedented plumes of methane – a greenhouse gas 20 times more potent than carbon dioxide [over a 100-year timespan] – have been seen bubbling to the surface of the Arctic Ocean by scientists undertaking an extensive survey of the region.
The scale and volume of the methane release has astonished the head of the Russian research team who has been surveying the seabed of the East Siberian Arctic Shelf off northern Russia for nearly 20 years. …
“Earlier we found torch-like structures like this but they were only tens of metres in diameter. This is the first time that we’ve found continuous, powerful and impressive seeping structures more than 1,000 metres in diameter. It’s amazing,” Dr Semiletov said.
“I was most impressed by the sheer scale and the high density of the plumes. Over a relatively small area we found more than 100, but over a wider area there should be thousands of them,” he said.
Let’s put that “1000 meters” into something Americans understand. These giant plumes are over half a mile wide. Not a half mile high — a half mile wide. Compared to their earlier observations, the plumes are now 100 times larger in just a few years. And yes, he did say there were likely “thousands of them.”
The path of deterioration will contain sudden collapses as well as gradual declines
Which leads to just two final thoughts, and then I’ll close.
First, just because the effects of climate change have been mostly gradual until now, doesn’t mean that gradual is all we’ll get. As I wrote recently:
"But there’s no reason to assume that there won’t be sudden collapses as well, sudden discontinuities, the way a steady dribble of small chunks of ice might fall from a Greenland glacier into the sea, then suddenly a piece the size of Ohio splits and floats away, lost, never to come back. A discontinuity, a break from the gradual.
"Discontinuities work in the social sphere as well, in the sphere of confidence and panic. As I’ll show you shortly, the first major (white) American city to end its life forever following a Haiyan-sized hurricane — Miami, for example — will cause a collapse in American confidence in the future that will never return. That loss of confidence and the panic that will result is a collapse as well, a discontinuity, fear the size of Ohio breaking the population from its safe assumptions and presumed security."
The Great Dying was a collapse, the largest in the history of life on the planet, though a slower paced one, since the volcanoes took a million years to fully erupt. Still, a massive methane proliferation caused it, and the initial effects must have been massive, since microbes grow and proliferate very quickly indeed (think “algae bloom”). If we succeed in getting most of the Arctic methane into the air in, say, 50 years, that will cause a collapse as well, and one at the geologic timescale of a nanosecond. Keep those thousands of half-mile wide plumes, rising through the ocean, in mind. A two-degree jump in warming, say, in only a few decades, would have huge consequences for anyone alive at the time — it would collapse the livability of the planet to a fraction of itself.
Second, all of this means that we really really need to take the timeline seriously, assume that we have far less time than we think we have, and act now. There’s a reason I’m being so aggressive lately about the need for a “Zero Carbon” + energy rationing regime (click for a short description) to get us off of all energy sources that produce greenhouse gases.
I don’t think I’m exaggerating the danger. The sudden ice ages discussed in this video occurred within decades of a warming event — yes, glacial ice just decades after a global warming event. That’s a collapse, and that’s sudden.
My ask of you is this. If you write, write this. We can’t allow our “leaders” — leash-holders might be a better term — to lead us to think the unicorn dream of “carbon neutral” will save us. “Carbon neutral” means the carbon car never stops, it just fails to accelerate. That doesn’t mean the climate itself won’t accelerate in its deterioration. Remember, there will be sudden collapses.
If you don’t write, you still have “reach.” Everyone who reads this has some reach. Please use it. People need to be told now, ahead of the inevitable panic that (1) we need to stop, not slow down; and (2) we can stop. We just have to.
I know many of your friends and associates won’t take you seriously … now. But they will, once the freak-out starts for real. Social panic is like a lynch mob. It starts suddenly and burns like a wildfire. Once the panic starts, people will need to have been already told points (1) and (2) above. After all, Lying Pantsuit Lady (i.e., the Exxon / methane industry spokesperson) is already telling your friends that the choice is carbon or no TV. She’s right, of course, but she’s selling the carbon. We should be messaging just as hard, so when they are ready to listen, they’ll have already heard what the answer is.
One last note — I hear people get depressed when they take this stuff seriously. Don’t. There’s a lot of ball game left, no collapse yet, still time on the clock, and lots of ways to mitigate. I’m personally excited by the idea that we can still get positioned for a chance opening, a good opportunity to make a big change.
Remember — winners know not to give up, just in case god has a gift in hand. Play to the whistle. After all, didn’t lowly Auburn beat Alabama, back when earth was cooler?
GP
Twitter: @Gaius_Publius. Facebook: Gaius Publi.
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