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My biggest fear today is that we're already screwed and just don't know it. This article turned out to be a "We expected this and now we've found it" but every

My biggest fear today is that we're already screwed and just don't know it. This article turned out to be a "We expected this and now we've found it" but every morning I worry I'll see a headline like this and it'll be "We turned over this one rock and found something we didn't expect. Prepare for global famine in 2 years." On our current course I'm quite optimistic that we'll be able to turn the ship around - I think between tech accelerating and the climate itself starting to put the screws on us, we'll have powerful enough tools and enough resources poured into them to save ourselves. However, that's if we stay on the apparent current course. I'm really scared we'll hit a discontinuity of some sort.

specialist 10y ago
We know it. Release of CO2 has entered a positive feedback loop. Thawing tundra, burning forests, ocean acidification. Even this we could counter (painfully) with massive industrial scale sequestration. What worries me is methane. I'm not sure we can mitigate methane released from the tundra. And if the stuff tucked under the ocean pops, we're toast. https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis
- semi-extrinsic 10y ago
  What I don't get about the positive feedback loop argument is that it seems completely at odds with what the IPCC is saying, namely limiting emissions in order to stabilize global warming at 2 degrees. If we were in a positive feedback loop, then global warming will just continue to accelerate no matter how small our emissions are. In fact, we'd be equally screwed if we magically stopped emitting CO2 in 1950, it would just take a little bit longer before we're screwed. Can anyone explain how to reconcile these arguments?
  - nikdaheratik 10y ago
    Methane doesn't stay in the atmosphere nearly as long which means that, in theory, it would cause some short term warming, but then the methane would break down and we would slowly return to more normal levels. There are alot of unknowns, and while a very worst case scenario involves runaway methane causing warming, we don't know how likely this is to happen. We do know that CO2 takes hundreds of years to dissipate and will cause the ice caps to melt which will lead to higher sea levels overall.
  - specialist 10y ago
    IPCC does consider tundra, methane, feedback loops. https://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch4s4-4-6.html https://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch4s4-4... Citations elided: "Arctic and sub-Arctic ecosystems (particularly ombrotrophic bog communities, see Glossary) above permafrost were considered likely to be most vulnerable to climatic changes, since impacts may turn Arctic regions from a net carbon sink to a net source. Literature since the TAR suggests that changes in albedo and an increased release of methane from carbon stocks, whose magnitudes were previously substantially underestimated, will lead to positive radiative climate forcing throughout the Arctic region."

specialist 10y ago

We know it. Release of CO2 has entered a positive feedback loop. Thawing tundra, burning forests, ocean acidification. Even this we could counter (painfully) with massive industrial scale sequestration. What worries me is methane. I'm not sure we can mitigate methane released from the tundra. And if the stuff tucked under the ocean pops, we're toast. https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis

semi-extrinsic 10y ago
What I don't get about the positive feedback loop argument is that it seems completely at odds with what the IPCC is saying, namely limiting emissions in order to stabilize global warming at 2 degrees. If we were in a positive feedback loop, then global warming will just continue to accelerate no matter how small our emissions are. In fact, we'd be equally screwed if we magically stopped emitting CO2 in 1950, it would just take a little bit longer before we're screwed. Can anyone explain how to reconcile these arguments?
- nikdaheratik 10y ago
  Methane doesn't stay in the atmosphere nearly as long which means that, in theory, it would cause some short term warming, but then the methane would break down and we would slowly return to more normal levels. There are alot of unknowns, and while a very worst case scenario involves runaway methane causing warming, we don't know how likely this is to happen. We do know that CO2 takes hundreds of years to dissipate and will cause the ice caps to melt which will lead to higher sea levels overall.
- specialist 10y ago
  IPCC does consider tundra, methane, feedback loops. https://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch4s4-4-6.html https://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch4s4-4... Citations elided: "Arctic and sub-Arctic ecosystems (particularly ombrotrophic bog communities, see Glossary) above permafrost were considered likely to be most vulnerable to climatic changes, since impacts may turn Arctic regions from a net carbon sink to a net source. Literature since the TAR suggests that changes in albedo and an increased release of methane from carbon stocks, whose magnitudes were previously substantially underestimated, will lead to positive radiative climate forcing throughout the Arctic region."