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Okay, the half-life of methane is 7-9 years. Not the lifetime. The 34x potential I gave is for methane over a hundred years. https://en.wikipedia.org/wiki/Glob

by zasz 10y ago

Okay, the half-life of methane is 7-9 years. Not the lifetime. The 34x potential I gave is for methane over a hundred years. https://en.wikipedia.org/wiki/Global_warming_potential https://en.wikipedia.org/wiki/Global_warming_potential It's incredibly potent stuff, so much that despite the relatively quick breakdown, an initial mass of methane will have a warming effect that is 20-35x that of an equivalent mass of carbon dioxide over a century. GWP numbers take the brief half-life of methane into account when calculated. You're making the mistake of looking at the absolute quantity of methane and short half-life, and thinking that it couldn't possibly have much of an effect. Well, people have already run the numbers, and it can have a huge effect. Current rates of methane leaks from mining natural gas could very well offset the benefits of moving away from coal: http://blog.nature.org/science/2016/06/24/natural-gas-coal-leak-rate-energy-climate/ http://blog.nature.org/science/2016/06/24/natural-gas-coal-l... Methane's very bad news, even in small quantities.

Retric 10y ago
The risk is from 100s's of Gigatons which is a extremely massive quantity. How much of that is going to be liberated and how soon has a massive impact on estimates. Anyway, your first link says " In the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, methane has a lifetime of 12.4 years" (If that's X ln(2) for half life it's 8.6 years) "This means that a methane emission will have 28 times the impact on temperature of a carbon dioxide emission of the same mass over the following 100 years." https://en.wikipedia.org/wiki/Atmospheric_methane https://en.wikipedia.org/wiki/Atmospheric_methane PS: As to small quantities, we are talking about billions of tons of a gas.
- zasz 10y ago
  The point of everything I have said is that it would take only a small quantity of methane, relatively speaking, to make a significant contribution to global warming. You don't need to emit as much methane as would match all the warming caused by current levels of CO2. Even an extra tenth of a degree is bad news. Every tenth of a degree shaves off a decade from the time we have to fix our planet. Any significant source of greenhouse gases.

by zasz 10y ago

Retric 10y ago

The risk is from 100s's of Gigatons which is a extremely massive quantity. How much of that is going to be liberated and how soon has a massive impact on estimates. Anyway, your first link says " In the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, methane has a lifetime of 12.4 years" (If that's X ln(2) for half life it's 8.6 years) "This means that a methane emission will have 28 times the impact on temperature of a carbon dioxide emission of the same mass over the following 100 years." https://en.wikipedia.org/wiki/Atmospheric_methane https://en.wikipedia.org/wiki/Atmospheric_methane PS: As to small quantities, we are talking about billions of tons of a gas.

zasz 10y ago
The point of everything I have said is that it would take only a small quantity of methane, relatively speaking, to make a significant contribution to global warming. You don't need to emit as much methane as would match all the warming caused by current levels of CO2. Even an extra tenth of a degree is bad news. Every tenth of a degree shaves off a decade from the time we have to fix our planet. Any significant source of greenhouse gases.