Not exact matches
A surprising recent
rise in atmospheric
methane likely stems from wetland emissions, suggesting that
much more of the potent greenhouse gas will be pumped into the atmosphere as northern wetlands continue to thaw and tropical ones to warm, according to a new international study led by a University of Guelph researcher.
In the quest to head off
rising global temperatures, some scientists have argued for steep curbs in how
much soot and
methane are released into the air.
The study observed active
methane plumes
rising from the seabed, but most of the gas was not from hydrates and
much of it did not reach the atmosphere.
Records of
methane levels, for example, indicate how
much of the Earth wetlands covered because the abundance of life in wetlands gives
rise to anaerobic bacteria that release
methane as they decompose organic material.
The worry is not so
much that there is already an abprupt release (though
methane concentrations are on the
rise) but that there are pathways for such abrupt release.
The likelihood of serious sea level
rise under «business as usual», and impacts on water resources may not have the acute drama associated with polar bear population decline or the possibility of massive
methane clathrate releases, but they are
much more likely to figure on policy makers agendas — just as other long term chronic issues (such as pensions) do.
The release of this trapped
methane is a potential major outcome of a
rise in temperature; it is thought that this is a main factor in the global warming of 6 °C that happened during the end - Permian extinction as
methane is
much more powerful as a greenhouse gas than carbon dioxide (despite its atmospheric lifetime of around 12 years, it has a global warming potential of 72 over 20 years and 25 over 100 years).
Records of
methane levels, for example, indicate how
much of the Earth wetlands covered because the abundance of life in wetlands gives
rise to anaerobic bacteria that release
methane as they decompose organic material.
This has never happened before because the sea ice never retreated very
much in the summer and the water temperature could not
rise above zero because of the ice cover... The permafrost is acting as a cap for a very large amount of
methane (CH4), which is sitting in the sediments underneath in the form of
methane hydrates.
«How
much will temperatures
rise for a doubling of CO2 and equivalents (increases in CO2,
methane, black carbon, ozone, nitrous oxide, and decreases in sulfate)?»
Professor Turetsky and her colleagues report that a recent
rise in atmospheric
methane probably stems from wetland emissions, suggesting that
much more will escape into the atmosphere as northern wetlands continue to thaw and tropical ones to warm.
Furthermore, the line representing the
rise in
methane which seemed to be exponentional untill 1990, quitted the curve around that year and became (
much) more flat.
As countries attempt to keep the global temperature
rise from passing 1.5 - 2.0 °C, how
much methane we release matters immensely.
Also, while we have good atmospheric measurements of other key greenhouse gases such as carbon dioxide and
methane, we have poor measurements of global water vapor, so it is not certain by how
much atmospheric concentrations have
risen in recent decades or centuries, though satellite measurements, combined with balloon data and some in - situ ground measurements indicate generally positive trends in global water vapor.»
Methane that escapes the sea is generally a small fraction of methane that is released from clathrates at the sea floor, though if the concentration rose high enough so much could make it to the atmosphere that the impact of methane as a GHG in air (before it devolves to CO2 in air) overwhelmed the negative effects of methane decomposing to CO2 in the o
Methane that escapes the sea is generally a small fraction of
methane that is released from clathrates at the sea floor, though if the concentration rose high enough so much could make it to the atmosphere that the impact of methane as a GHG in air (before it devolves to CO2 in air) overwhelmed the negative effects of methane decomposing to CO2 in the o
methane that is released from clathrates at the sea floor, though if the concentration
rose high enough so
much could make it to the atmosphere that the impact of
methane as a GHG in air (before it devolves to CO2 in air) overwhelmed the negative effects of methane decomposing to CO2 in the o
methane as a GHG in air (before it devolves to CO2 in air) overwhelmed the negative effects of
methane decomposing to CO2 in the o
methane decomposing to CO2 in the oceans..
Since a sustainable future based on the continued extraction of coal, oil and gas in the «business - as - usual mode» will not be possible because of both resource depletion and environmental damages (as caused, e.g., by dangerous sea level
rise) we urge our societies to -LSB-...] Reduce the concentrations of warming air pollutants (dark soot,
methane, lower atmosphere ozone, and hydrofluorocarbons) by as
much as 50 % [and] cut the climate forcers that have short atmospheric lifetimes.
This leads me to believe that CO2 forcing is a minor component of the temperature
rise (even Hansen in his paper «Global Warming in the 21st century, an Alternative Scenario» has assigned
much warming to e.g. black carbon,
methane etc, and an inquisitive mind might easily think of others such as albedo change).
Isakower said at a time when oil and natural gas production has
risen dramatically,
methane emissions have fallen because of industry leadership, investment in new technologies and incentives to capture as
much methane as possible for delivery to consumers:
If, on the other hand, a
methane release to the atmosphere continues for
much longer than the
methane lifetime, the concentration of
methane in the atmosphere will
rise to a new steadystate value.
RealClimate is wonderful, and an excellent source of reliable information.As I've said before,
methane is an extremely dangerous component to global warming.Comment # 20 is correct.There is a sharp melting point to frozen
methane.A huge increase in the release of
methane could happen within the next 50 years.At what point in the Earth's temperature
rise and the
rise of co2 would a huge
methane melt occur?No one has answered that definitive issue.If I ask you all at what point would huge amounts of extra
methane start melting, i.e at what temperature
rise of the ocean near the Artic
methane ice deposits would the
methane melt, or at what point in the
rise of co2 concentrations in the atmosphere would the
methane melt, I believe that no one could currently tell me the actual answer as to where the sharp melting point exists.Of course, once that tipping point has been reached, and billions of tons of
methane outgass from what had been locked stores of
methane, locked away for an eternity, it is exactly the same as the burning of stored fossil fuels which have been stored for an eternity as well.And even though
methane does not have as long a life as co2, while it is around in the air it can cause other tipping points, i.e. permafrost melting, to arrive
much sooner.I will reiterate what I've said before on this and other sites.
Methane is a hugely underreported, underestimated risk.How about RealClimate attempts to model exactly what would happen to other tipping points, such as the melting permafrost, if indeed a huge increase in the melting of the methal hydrate ice WERE to occur within the next 50 years.My amateur guess is that the huge, albeit temporary, increase in
methane over even three or four decades might push other relevent tipping points to arrive
much,
much, sooner than they normally would, thereby vastly incresing negative feedback mechanisms.We KNOW that quick, huge, changes occured in the Earth's climate in the past.See other relevent posts in the past from Realclimate.Climate often does not change slowly, but undergoes huge, quick, changes periodically, due to negative feedbacks accumulating, and tipping the climate to a quick change.Why should the danger from huge potential
methane releases be vievwed with any less trepidation?