Runaway Global Warming - Has Arrived

coyote

2002... that makes sense to me as a layman, it seems like it was this decade that everything started speeding up.

What do you guys think of Lovelock's thesis that the Earth will have a harder time getting back to 'status' temperature this time, due to the sun being hotter than it was in past periods of drastic warming?
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ReverseEngineer · Light Sweet Crude Joined: Jul 16, 2008 Posts: 1722

As Tanada indicated, the general feedback mechanisms of the earth tend to keep the overall temperature within a fairly limited range. I don;t think a marginal increase in output from the Sun would affect this all that much.

However, the timespan to revert back to a climate like we had in say 1980 from what we have now or are likely to see in the coming years won't happen on near the same timescale as the descent does. Clearing out of the atmosphere all the sutff we dropped into it will take time in itself, and then to reuptake all that methane takes still further time. Timespan here starts getting Geologic, I can't envision a turn around in less than 10,000 years. However, the intervening 10,000 I don't see as unsurvivable unless it leads to mass extinction rapidly in the oceans.

This one is the biggest wild card. Death of the Coral Reefs has made the breeding grounds for many species of fish unsupported, but numerous species do have high tolerance for low Ph and still breed OK. With a significant human species reduction and less pressure on the oceans from this end, some species might come to occupy niches where other species have vacated from die of. You don't have to have immediate genetic mutations to cover this problem.

As opposed to most species in prior die offs, human beings are highly adaptable to a variety of environments and a variety of foods. You can even eat Algae if need be. Obviously however in cities around the world, the supply of Algae to eat won't be great, and under any scenario you look at a very large reduction in total population. This however reduces stress on the biosphere, and some organisms will be able to make use of the higher temps and productively convert carbon into other organic chemicals we can eat or feed to other animals or just burn.

Entirely wiping out Humanity won't happen easily or quickly, certainly not inside 20 years anyhow except with Global Thermonuclear Warfare. However, you could see a very large die off in that period. Mass extinction at least at this point just based on the Ice Cap melting seems like a very big stretch to me.

Reverse Engineer

jbrovont · Intermediate Crude Joined: Jun 16, 2006 Posts: 701

I had a couple thoughts while reading this thread. The 95% extinction rate will favor the small and simple. If we're talking about "all species," we can probably kiss anything warm and fuzzy good bye. As far as the number of species go, we're the most complex and thus represent the smallest in sheer numbers of species. Bugs and jellyfish might be a safer bet.

Secondly, as the ocean warms, the solubility of a gas in the liquid will fall. When the article Cid quoted "super saturated," if they're using the word's scientific definition, it means that no more methane can dissolve in it. If more is released, it will bubble out, or force other gas molecules out of solution (gas).

It also means that a very small increase in water temperature will result in a rapid release of methane from the water itself, just like boiling water forces air out of solution.

dohboi · Light Sweet Crude Joined: Dec 05, 2005 Posts: 1475

Good points, jb.

RE wrote, "numerous species do have high tolerance for low Ph and still breed OK." That's important to remember, but acidity is not the only threat, and is not only a direct threat. Acidity kills of plankton that form the base of the food chain. So it doesn't help much if you can tollerate acid conditions if all your food is gone. And another issue is if/when the ocean goes anoxic because of shut down of the thermo-halide circulation. That, as I understand it, was the biggest cause of sea death, and the anoxic decomposition of all those dead fish lead to the generation of enormous clouds of hydrogen sulfide which very efficiently did a lot of the extinction work on land. A great irony is that our vacuuming of most of the edible fish in the sea may have reduced the mass of material that would have contributed to these H2S clouds--one set of extinctions and near extinctions perhaps ameliorating another one?

Back to the original post on super-saturation of the Arctic Ocean with methane--the article said, I believe, that the readings were taken near the mouth of the Lena River. This is a major estuary that drains much of the Siberian tundra. There have been reports for the last year or two of northern Siberian lakes boiling with methane as the permafrost beneath melts for the first time in millennia. I'm guessing that most of the increase in methane saturation at the mouth of the Lena is from run off from thousands of such lakes and swamps. Just a guess.

Not good news, but readings in that particular location aren't necessarily the best indication for what is happening at this moment elsewhere in the Arctic. More data from around the continental shelves up there would be useful, but ultimately academic. Total melt of the Arctic or any thing near it can only mean massive off-gassing of methane hydrates from at least the shallower waters. The best case scenario is that it happens gradually enough that most of it oxidizes to CO2, but that isn't great either, of course.

The turning point was probably back in the '80s or a bit earlier, when the Arctic started its steady decline. That's why folks over at www.carbonequity.info think we should aim to reduce atmospheric CO2 to levels from that period--a good idea, but I don't see it happening any time soon, and we're well on our way to spinning wildly out of control.

Cid_Yama

dohboi, You must have missed this article:

Methane gas oozing up from Siberian seabed: Swedish researcher
Methane, a potent greenhouse gas, is leaking from the permafrost under the Siberian seabed, a researcher on an international expedition in the region told Swedish daily Dagens Nyheter on Saturday.

"The permafrost now has small holes. We have found elevated levels of methane above the water surface and even more in the water just below. It is obvious that the source is the seabed," Oerjan Gustafsson, the Swedish leader of the International Siberian Shelf Study, told the newspaper.

The tests were carried out in the Laptev and east Siberian seas and used much more precise measuring equipment than previous studies, he said.

Methane is more than 20 times more efficient than carbon dioxide in trapping solar heat.

Scientists fear that global warming may cause Siberia's permafrost to thaw and thereby release vast amounts of methane into the atmosphere. The effects of global warming are already most visible in the Arctic region. link
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dohboi · Light Sweet Crude Joined: Dec 05, 2005 Posts: 1475

Thanks for pointing out that passage. I was a bit groggy and wistful as I wrote that.

Back to super doomer mode.

"Methane is more than 20 times more efficient than carbon dioxide in trapping solar heat."

This is the usual figure cited, but it is misleading. Methane is 20+ times more efficient than CO2 over the time scale of a century. But that's just because for most of that century, most of the methane is no longer around while the CO2 is. In short-term, decadal time scales, more relevant to what we are talking about as far as immediate consequenced of near-term, massive methane release, methane is 100+ times more efficient than CO2 in trapping heat. That's why you can have such strong reactions in temperature so quickly.

By the way, I wouldn't want to be sailing around above those methane releases. Sudden burps of methane can essentially turn a column of water in air.

dorlomin · Light Sweet Crude Joined: Aug 05, 2007 Posts: 1151

Just posted this in the arctic thread but its worth a wee look here.
Aug 2008 Chart

Link 5 degrees warmer in the shallow waters. However I am still waiting before going mega doomer, the increases in methane may come from increased decomposition on the arctic sea floor or other biological or geological sources as much as melthing methane clatherates.

If this is what it looks like mind, it may be time for last ditch geoengineering. Something like loads of aircraft pumping SO2 or other cooling gasses over the arctic during the summer month to reflect some of the incomoning solar energy while we buy ourselves time to power down and batten down the hatches.

Cid_Yama

Come on, everybody sing! link
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JustaGirl

Cid_Yama · Last edited by Cid_Yama on Sun Aug 31, 2008 6:31 pm; edited 4 times in total

Methane carbon in the form of gas hydrates, on the other hand, is isotopically very 'light,' meaning that has a very low carbon C13/12 ratio. Gas hydrate is a "solid, ice-like substance, composed of rigid cages of water molecules that enclose molecules of gas, mainly methane" (Kevenholden). Massive amounts of methane hydrates (1x10^19 - 2x10^19g) exist in continental slope sediments today, at depths greater than ~400-1000m. It is assumed that a similar amount existed in the Permian. Methane has a delta 13C value of -60, and calculations show that the P-Tr carbon isotope changes could be produced by dissociation of between 10 and 25% of existing resevoirs.

The other explanatory advantage is that, unlike the buried organic carbon resevoir, the methane resevoir can be rapidly discharged into the ocean-atmosphere system, by oceanic warming. Converted to the gaseous state, the methane rapidly diffuses into the ocean and the atmosphere, is oxidized by methanotropic bacteria to form light CO2 and water [CH4+2O2->2H20+CO2]. The light CO2 is mixed with the oceans and atmosphere and incorporated into carbonates and organic matter, thus producing the observed carbon isotopic shift.

Methane and CO2 are both greenhouse gasses. Thus, once methane begins to dissociate, the ocean-atmosphere system warms even more, releasing even more methane, etc., and a positive feedback is initiated. Perhaps the warming was initiated by volcanism, and the coup de grace was delivered by methane dissociation.

link

But it was not only that the recovery ushered in a dramatically different biota from that which had gone before. The recovery after the end of the Permian was delayed for millions, perhaps tens of millions of years. The Permian extinction event had left a depleted planet, one where the survivors had to face challenges for which the evolutionary process had not prepared them. Nearly all of the organisms with which they had shared the Earth were gone: the plants the herbivores consumed, prey and predators, disease organisms as well as helpful symbionts. The entire biosphere required readjustment and reorganization. During the millions of years which followed the end of the Permian, the survivors struggled with exceptionally harsh and unfamiliar conditions. The immediate post-Permian world, however, does provide insight into the nature of the catastrophe itself.

link

Tanada, your premise is flawed. There are no feedback boundaries. Certainly not ones that guarantee a habitable world for humans.
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Tanada

Tanada

Cid_Yama

The Permian-Triassic Extinction Event disproves your assertion.

You might try reading about it. I provided links. You know a whole lot less about the geological history of this planet than you think you do.

Methane Bubbling Through Seafloor Creates Undersea Hills

From 2003:

Paull suspected that the submarine pingos had formed beneath the sea, and that they might still be forming. This was why he had come to the Arctic. About five years before, he and fellow geologist Bill Ussler had written a National Science Foundation (NSF) grant proposal to investigate methane hydrates in sea-bottom sediments and their relationship to submarine pingos. The NSF had turned down his proposal with the comment that submarine hydrate research was not a research topic they were interested in funding.

Within the next few years, however, funding agencies became vitally interested in Arctic processes, global warming, and gas in sea-bottom sediments. Scientists learned that huge volumes of methane were locked up in oceanic sediments, mixed with frozen water to form methane hydrates. Some even suggested that these hydrates could have triggered extreme shifts in the Earth's climate by suddenly releasing vast amounts of methane (a greenhouse gas) into the atmosphere.

With undersea methane becoming a hot topic, Paull and Ussler decided to resubmit their proposal. As Paull put it, they simply asked the question, "Why don't we go and see what it takes to get gas released from methane hydrates today?" They pointed out that the Arctic Ocean was a logical place to look for such releases because hydrates in this area had been slowly warming since the end of the last ice age, more than 10,000 years ago.

They also suggested that, rather than searching the entire Arctic ocean for dissolved gas, scientists should look for geological features that might indicate where gas was emerging from the sediment. Submarine pingos were one such feature. Similarly, gas might also be found around submarine pockmark fields, where the sea bottom is scarred by hundreds of meter-deep pits in the sea floor.

They spent the next three weeks dodging pack ice and shallow water while collecting about eighty sediment cores in and around half a dozen submarine pingos and two pockmark fields. This was their primary mission—to take samples of mud and ice and to analyze the water and gas within these samples. Specifically, they wanted to find out if gas was trapped in the sediment, and if so, determine what kind of gas it was and where it was coming from.

To their surprise and delight, the researchers found plenty of gas in cores from the submarine pingos. They also used a small remotely operated vehicle (ROV) to record video of gas bubbling out of the tops of two submarine pingos. Encouraged by this finding, Ussler decided to try and obtain a sample of this gas. Improvising with some decidedly low-tech tools, including an old funnel and a large plastic syringe, he succeeded in converting the small ROV into a submarine gas-collection system. He also used a small boat, a plastic bucket, and his bare hands to collect gas bubbling to the sea surface—no mean feat in frigid Arctic water.

Early results from the geochemical analyses are intriguing. For example, the gas emerging from the submarine pingos appears to be nearly pure methane. This suggests that it did not originate from a natural gas reservoir that lies deep below the sea floor in this area. In addition, water in the submarine pingo cores is only half as salty as water in the surrounding sediments, suggesting that it came from buried freshwater ice rather than from the overlying seawater.

link

Conclusions 2007:

Even with evidence that pingo-like features were made of older, deeper sediment that had been pushed up from beneath the seafloor, the geologists still had to figure out what geologic process could generate enough pressure to lift seafloor sediments. The most obvious source of such pressure was methane gas, which the researchers observed bubbling out of the tops of several pingo-like features. After chemically analyzing this gas, the researchers concluded that it originated as methane hydrate, an ice-like mixture of water and methane that forms within sediments under much of the Arctic seafloor and beneath permafrost areas on land. Methane hydrate can only remain solid at low temperatures and high pressures. Such conditions exist several hundred meters below the seafloor in this part of the Arctic Ocean.

The researchers suggested that such buried hydrates might be decomposing and releasing large amounts of methane gas. This seemed possible because the seafloor in this area has been gradually warming over the last 10,000 years, after being flooded as sea levels rose at the end of the last ice age. Although within a few degrees of freezing, the seawater in this region is at least 10 degrees Centigrade (20 degrees Fahrenheit) warmer than permafrost-filled soil. Thus, when the ice sheets from the last ice age melted and the ocean flooded the continental shelves, it caused the seafloor sediment to become warmer.

Over thousands of years, the scientists believe, this "wave" of warming moved downward through the sediment. Eventually it reached the frozen methane hydrates, hundreds of meters down. Even a slight temperature increase could have caused some of the buried methane hydrates to decompose, releasing methane into the surrounding sediments.

Paull and Ussler's data suggest that this newly released methane migrated sideways under the seafloor, held in place by an impermeable layer of frozen soil that lies between the hydrates and the seafloor. Eventually it collected and moved toward the surface along faults or in other areas where the sediments were relatively weak.

Eventually the extruded sediment collected to form the low undersea hills visible on bathymetric charts. At the same time, areas on either side of the mounds, where much of the gas and sediment originated, slowly collapsed, forming the deeper "moats" observed by the researchers.

link
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In a time of universal deceit, telling the truth is a revolutionary act. - George Orwell

It riles them to believe that you perceive the webs they weave. - Moody Blues