More Believe In Space Aliens Than In God According To U.K. Survey

[regexcellent]

There's a very strong diminishing return to adding more carbon dioxide to the atmosphere, in terms of its effect on how much radiation can escape (something I forgot to add). Basically, suppose x quantity of carbon dioxide stops 50% of radiation from escaping. Adding another x CO2 stops 50% of the remaining radiation from escaping.

300 parts per million iirc is ballpark around the point where the diminishing returns start to have a large impact. Again this is all from memory but I know that the commonly cited "critical number" was passed in the early 1900s.

There are no workable existing policy proposals that would significantly alter the level of CO2 in the atmosphere. Hybrid cars and won't make a huge dent. And anything we do in the United States will just be undone by the growing economies in Asia. So really any policy on global warming is pointless.

[Aeson]

Carbon dioxide also takes a while to work its way out of the atmosphere, much longer than most other greenhouse gasses. That's why nobody really worries about methane or water vapor; they have a short lifespan in the atmosphere.

Actually, methane has a much larger greenhouse effect than CO2, even over very long time spans (centuries). The main reason not to care as much about it is that anthropogenic methane emissions tend to be better than the alternatives when looked at holistically (leakage from natural gas vs using coal), or are insignificant contributors no one sane wants to give up (bacon and butter).

CO2 is actually one of the least harmful greenhouse gases for any given number of particles, we just pump a relatively large amount of it out.

[regexcellent]

Methane has about 4x the greenhouse effect but iirc its half-life in the atmosphere is much shorter. Water vapor has a massively higher greenhouse effect but its half life in the atmosphere is very short, like a couple weeks or something.

[Aeson]

And anything we do in the United States will just be undone by the growing economies in Asia. So really any policy on global warming is pointless.

No. The developed world can certainly impact the path that developing countries will take. We do this (and can do it more) by developing tech and scaling up production of green technology to make it cheaper for them to do so themselves. If we were to do nothing, we guarantee the worst possible result (whatever that may be).

[Aeson]

Methane has about 4x the greenhouse effect but iirc its half-life in the atmosphere is much shorter.

I am talking about GWP (GWP of 1 = CO2), which already factors in time in the atmosphere.

http://en.wikipedia.org/wiki/Greenhouse_gas

Methane has an atmospheric lifetime of 12 ± 3 years and a GWP of 72 over 20 years, 25 over 100 years and 7.6 over 500 years. The decrease in GWP at longer times is because methane is degraded to water and CO2 through chemical reactions in the atmosphere.

Methane is much worse on a particle by particle basis even over 500 years.

[kentonio]

That's why nobody really worries about methane or water vapor; they have a short lifespan in the atmosphere.

No-one worries about methane? The vast deposits of methane trapped in the Antarctic are one of the things people are MOST worried about.

As an example, the Antarctic ice sheet has been growing rapidly for the past decade and nobody really knows why.

Here's an article explaining the Antarctic ice growth, and why it's not anything to feel reassured by.

http://news.nationalgeographic.com/n...e-environment/

I think the most promising proposals for dealing with global warming involve some kind of geoengineering. That has its own (rather enormous) set of risks associated with it so I won't go so far as to actually advocate it.

That's a very familiar climate sceptic position, relying on some undefined potential magic fix. As you quite rightly point out the risks attached to those kind of projects is indeed absolutely enormous. We can't just ignore everything the scientists are telling us and hope that science will just provide some easy super answer later.

You mentioned that people keep linking disasters to global warming, well yes when weather patterns are increasingly going crazy that isn't a wildly unreasonable assumption. Demanding absolute 100% proof of something that could decimate our species before we do anything to act on it is not a reasonable request.

[regexcellent]

I'm in the "do nothing and live with it" camp. Also I'm not using the Antarctic ice sheet as a reason to believe global warming is fake. I am using it as an example of how the popular media version of global warming is an unfalsifiable religion, in the same vein as Katrina, the Queensland floods, the "snowpocalypse" in 2010, etc.