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Comment by Retric | Hacker News Reader

Unlike CO2 Methane has a half life of ~7 years in the atmosphere, thus front loading warming before breaking down into CO2 and water. So, in terms of climate impact in 2040+, natural gas burned today is significantly better than coal.

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In 2040 methane emitted today will still be 86x more potent than co2. Co2 emissions from natural gas are 50% that of coal. So todays natural gas with a 1% leakage rate will still have 135% of the warming impact of coal in 2040.

By 2120 the methane emitted today will be 34x as potent as co2. So todays natural gas with a 1% leak rate will have 84% of the impact on warming that you would get from coal.

So if you can keep leakage to 1% (it hasn't been that low and efforts to regulate it to those levels have been attacked by republicans.) Then by sometime around 2100 it should be coming down to the same impact as coal.

This bridge fuel/front loading of the warming strategy would have been great in 1970 and 1980. Today it really doesn't make any sense.

But this potency will be in the past, as all the methane broke down in 2100. The effect of a warmer day now will surely be negligible a 100 years in a future and climate instead find a new equilibrium?

You’re vastly off. Averaged over 20 years methane is (GWP) 104x as potent as CO2, averaged over 100 years it’s (GWP) 28x. But, to get that average you can calculate ((28 * 100) - (104 * 20)) / 80 = 9. So, from year 20 to year 100 it’s 9x as potent on average. You get this because 1 - (1/(2^(20/7)) = 86% of methane released today has broken down in 20 years.

Further, methane goes from CH4 atomic weight 18 to CO2 atomic weight 44. Thus, after breakdown you get (44/18) = 2.75x as much CO2 by weight. So, in 2120 methane produced today will be 99.995% CO2 and provide ~2.75x as much warming vs CO2 emitted today.

Edit: Updated with numbers from https://en.wikipedia.org/wiki/Atmospheric_methane

That makes sense. Do you know if there is a graph that illustrates this so it cements in my mind better?

I wonder how much feedbacks are considered with this. The early pulse of warming can cause changes to alebedo, co2 and methane emissions from melting permafrost, etc that carry on after the initial methane has broken down.

The graph is just a log decay like all chemical degradation curves.

https://skepticalscience.com/toward-improved-discussions-met...

The world is not going to end due to climate change in 2100 or 2200. Humans are capable of adapting to developing climates. The Earth is not going to burn to ashes, the most likely scenario are a few degrees higher which will absolutely have an impact but I don't buy the doomsday scenario. Deaths due to catastrophic events have been going down each decade. Population displacement due to flooding is overstated as we are capable of adapting to incremental flooding due to climate change. My point is, let's take gas now as an improvement and work on solutions over time. We can reasonably expect that by 2100 most cars will be electric or some other clean energy fuel. Climate change will not be solved due to international cooperation, this is an intractable cooperation problem. We are beating climate change with human ingenuity but it takes time...

"Humans" can adapt as a general abstraction, but we're all too happy to let individual humans die, particularly if they're poor or in developing countries.

Even if you write off those deaths as irrelevant, it still costs money to adapt, as infrastructure has to be built or abandoned and rebuilt, and human capital has to be moved along with it.

It is not clear to me that poor countries are to experience human loss due to climate change since there is a trade off in place here. If developed and developing countries curb emissions to near net zero levels the world economy will suffer. For instance, people in developing countries are still dying from malnutrition. Preventing enhanced economic global prosperity may affect human lives more than the counterfactual scenario of current emission levels. I am not saying this is true, but I think this question is valid. Of course, it would be ideal if we could stop CO2 emissions without foregoing economic growth but such scenario is not possible as of today. That's why I think the solution will come via technological advances instead of global cooperation to reduce CO2 emissions. Even though I do live in a developed country, I came from a developing country and many of you with the same background as me knows that climate change is the least of their worries when some don't even know what they are going to eat for dinner. My point is, in the absence of a global governance structure that makes prohibitively costly to implement a drastic reduction in CO2 emissions worldwide, there is no way that people in the developing world will choose less economic development. I know climate change is dear and near to many people's hearts here but as far as the consequences are not dramatic and sudden, people in the developing world will not really care except for the rich and upper middle class in developing countries which includes some of the biggest emitters such as China.

These same countries never installed land line telephone networks and yet most people in the developing world have phones now because cell phone technology came down in cost enough to outcompete any attempt at building out landline infrastructure.

As solar and wind and storage prices are are coming down fast there is good reason to expect the developing world to be able to largely be able to leapfrog fossil fuels and electrify without the expensive cost of building centralized power plants with sprawling networks of transmission lines, substations and local power lines stretching for thousands and thousands of miles zigzagging through the country side.

Same with electric cars. We are getting close to a day when electric cars will be on sale with 200+ miles of range for 22,000 that has 1/10th the cost to operate as a equivalent internal combustion engine.

The idea that fossil fuel consumption is neccessary for economic growth and standard of living is outdated. Many nations economies have already decoupled growth from fossil fuel consumption. Reducing co2 emissions while simultaneously growing their economies. Including the US.

My argument would be that some kind of coordinated global price on carbon would be an economically cheaper way to prevent and mitigate climate change than arbitrary and unbounded externalization of the costs of it on individuals.

I agree with you that there's a deep and fundamental coordination problem, which is why de facto I think technological solutions will be what have to save us. Which is basically putting many millions of lives at stake with a hope and a prayer, but that's the best we have.

If you have a bunch of gas infrastructure leaking constantly, the powerful methane is actually far worse for climate, molecule for molecule, because the methane level will equilibriate high and cause constant high warming as long as the infrastructure is operating and leaking.

If it breaks down into CO2 after the 7 years doesn’t that mean it continues to be a climate changing element?

It’s a question of scale. Methane is useful fuel, so leaks are an exception rather than the most common result. Spilled gasoline when fueling your car also results in atmospheric CO2, but you produce vastly more CO2 from what ends up in your tank.

There is plenty of evidence that leakyness is a common feature of natural gas infrastructure.

The Methane being leaked is 86x more potent than co2 over 20 years and 34x more potent over 100 years.

At 1% leakage todays natural gas emissions don't gain a climate advantage over coal until around 2100. At 2% leakage todays natural gas emissions are still significantly worse than coal in 2100.

https://www.technologynetworks.com/applied-sciences/news/glo...

http://theconversation.com/the-us-natural-gas-industry-is-le...

https://en.m.wikipedia.org/wiki/Global_warming_potential

Interesting. Oil companies frack to get petroleum, and are OK with burning the natural gas at the well head. I get the impression that a big reason they choose to capture the natural gas instead is criticism of just burning it by environmentalists, but maybe it is more environmentally friendly to just burn it in the absence of the political will to ban fracking. (I am assuming that burning at the well head is an effective way to reduce the amount of unburnt gas released.)

Apparently I misunderstood how it works. Averaged over 100 years its 34x more potent, but the vast majority of the impact is early on.

They flare it where there is no infrastructure or insufficient infrastructure to get the gas to market. There are limits on what can be flared and this is what drives some of the decision making. However, if sufficient infrastructure exists they are literally burning money by flaring the gas or just letting it evaporate into the atmosphere.

It breaks down by half over 7 years. 7 years is the half life not the lifespan. Also yes it continues being a greenhouse gas even after it breaks down. So the "Global warming potential" of a ton of methane leaked to atmosphere starts out extremely high.

(Edit: I misunderstood this next part. It's potencies here are averaged over that period of time. Most of the impact comes at the begining.)

After 20 years it is 86x more potent than co2 and after 100 years it is 34x more potent. It never becomes less potent than co2 because it eventually becomes co2.

Yes, I understand half-lives. my point was that even after breaking down it continues to contribute to the changing of the climate.

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