Anyone who has been following the global events of the past three plus decades and has been doing so without political rose colored glasses on knows that what we are experiencing on planet Earth at this point in time is unlike anything we have experienced in the whole of human existence. CO2 PPM is at an unprecedented global high with our oceans warming at an increasing rate and acidifying more than they have been in thousands of years. Glaciers globally on the whole are melting as we see unprecedented melting continuing to take place in the Arctic. Climate change, the effect of global warming and our continued experiment on the atmosphere is now upon us and its effects including more of our planet experiencing extreme weather in response to our human forcing upon our climate, carbon and hydrologic cycles is evident with scientific reports warning us that continued effects will become worse particularly regarding water and food supplies.
Scientists now look at this new epoch beginning as the Anthropocene- the epoch where human influence on our planet is now being seen. The questions this particular post aims to examine are just how far will that human forcing go and how fast will the effects of it happen? If you look at the political answer to those questions, the amount of time to begin to address it is not nearly as urgent as it should be. For purposes of their climate meetings where they sit bickering over which country should foot the bill while coming to no real conclusions or solutions, they deem 2 degrees Celsius to be the point at which we really have to start taking action. I don't know what they are thinking about beyond their benefactors but after seeing the global effects of a close to 1.0 increase already it is clear we must address this now.
Discussing the culmination of the effects of this based not just on science but on our consumerism, industrialization, globalization, greed, hubris and political partisanship that impedes true progress on the climate front also requires that the effects of feedbacks (particularly methane clathrates) must be addressed and taken more seriously. We really do not know how much or how little of a forcing could catapult the planet into abrupt warming and at the rate we are consuming fossil fuels and depleting our carbon budget that point may be much sooner than we know :
Large Release of Methane Could Cause Abrupt and Catastrophic Climate Change as Happened 635 Million Years Ago, UCR-led Study Warns
An abrupt release of methane, a powerful greenhouse gas, about 635 million years ago from ice sheets that then extended to Earth’s low latitudes caused a dramatic shift in climate, triggering a series of events that resulted in global warming and effectively ended the last “snowball” ice age, a UC Riverside-led study reports.
The researchers posit that the methane was released gradually at first and then in abundance from clathrates — methane ice that forms and stabilizes beneath ice sheets under specific temperatures and pressures. When the ice sheets became unstable, they collapsed, releasing pressure on the clathrates which began to degas.
“Our findings document an abrupt and catastrophic means of global warming that abruptly led from a very cold, seemingly stable climate state to a very warm also stable climate state with no pause in between,” said Martin Kennedy, a professor of geology in the Department of Earth Sciences, who led the research team.
“This tells us about the mechanism, which exists, but is dormant today, as well as the rate of change,” he added. “What we now need to know is the sensitivity of the trigger: how much forcing does it take to move from one stable state to the other, and are we approaching something like that today with current carbon dioxide warming.”
Study results appear in the May 29 issue of Nature.
According to the study, methane clathrate destabilization acted as a runaway feedback to increased warming, and was the tipping point that ended the last snowball Earth. (The snowball Earth hypothesis posits that the Earth was covered from pole to pole in a thick sheet of ice for millions of years at a time.)
“Once methane was released at low latitudes from destabilization in front of ice sheets, warming caused other clathrates to destabilize because clathrates are held in a temperature-pressure balance of a few degrees,” Kennedy said. “But not all the Earth’s methane has been released as yet. These same methane clathrates are present today in the Arctic permafrost as well as below sea level at the continental margins of the ocean, and remain dormant until triggered by warming.
“This is a major concern because it’s possible that only a little warming can unleash this trapped methane. Unzippering the methane reservoir could potentially warm the Earth tens of degrees, and the mechanism could be geologically very rapid. Such a violent, zipper-like opening of the clathrates could have triggered a catastrophic climate and biogeochemical reorganization of the ocean and atmosphere around 635 million years ago.”
Today, the Earth’s permafrost extends from the poles to approximately 60 degrees latitude. But during the last snowball Earth, which lasted from 790 to 635 million years ago, conditions were cold enough to allow clathrates to extend all the way to the equator.
According to Kennedy, the abruptness of the glacial termination, changes in ancient ocean-chemistry, and unusual chemical deposits in the oceans that occurred during the snowball Earth ice age have been a curiosity and a challenge to climate scientists for many decades.
“The geologic deposits of this period are quite different from what we find in subsequent deglaciation,” he said. “Moreover, they immediately precede the first appearance of animals on earth, suggesting some kind of environmental link. Our methane hypothesis is capable also of accounting for this odd geological, geochemical and paleooceanographic record.”
Also called marsh gas, methane is a colorless, odorless gas. As a greenhouse gas, it is about 30 times more potent than carbon dioxide, and has largely been held responsible for a warming event that occurred about 55 million years ago, when average global temperatures rose by 4-8 degrees Celsius.
When released into the ocean-atmosphere system, methane reacts with oxygen to form carbon dioxide and can cause marine dysoxia, which kills oxygen-using animals, and has been proposed as an explanation for major oceanic extinctions.
“One way to look at the present human influence on global warming is that we are conducting a global-scale experiment with Earth’s climate system,” Kennedy said. “We are witnessing an unprecedented rate of warming, with little or no knowledge of what instabilities lurk in the climate system and how they can influence life on Earth. But much the same experiment has already been conducted 635 million years ago, and the outcome is preserved in the geologic record. We see that strong forcing on the climate, not unlike the current carbon dioxide forcing, results in the activation of latent controls in the climate system that, once initiated, change the climate to a wholly different state.”
End of Excerpt
Also see:
Methane Hydrate Feedback
Also see:
Study Finds Climate Changing Methane Rapidly Destabilizing Off East Coast
A changing Gulf Stream off the East Coast has destabilized frozen methane deposits trapped under nearly 4,000 square miles of seafloor, scientists reported Wednesday. And since methane is even more potent than carbon dioxide as a global warming gas, the researchers said, any large-scale release could have significant climate impacts.
Temperature changes in the Gulf Stream are "rapidly destabilizing methane hydrate along a broad swathe of the North American margin," the experts said in a study published Wednesday in the peer-reviewed journal Nature.
Using seismic records and ocean models, the team estimated that 2.5 gigatonnes of frozen methane hydrate are being destabilized and could separate into methane gas and water.
It is not clear if that is happening yet, but that methane gas would have the potential to rise up through the ocean and into the atmosphere, where it would add to the greenhouse gases warming Earth.
The 2.5 gigatonnes isn't enough to trigger a sudden climate shift, but the team worries that other areas around the globe might be seeing a similar destabilization.
This is one place seeing such destabilization:
Thawing Permafrost: The speed of coastal erosion in Eastern Siberia has nearly doubled
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As we continue to survey the effects of warming we are now seeing in the Arctic and our oceans this scenario does become more possible when paired with humanity's incessant rapacious consumption of fossil fuels and time lag effects.
Record Levels Of Greenhouse Gases Raise Concern Over Climate Change
As was discussed in my post regarding our carbon debt we are limited in the amount of fossil fuels we can continue to burn in order to not pass a threshold which will make this irreversible.
This threshold plus the mitigating circumstances that could lead us to abrupt climate change faster than we think and the urgent moral action we need to take now will be the topic of the next entry coming this week.
Part 2: Methane Feedback And Abrupt Climate Change
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