5 ms·

We're definitely going to go beyond 2ºC in the coming decades. Even if a miracle happened and we stopped all human emissions today, current GHGs in the atmosph

by pier25 5y ago

We're definitely going to go beyond 2ºC in the coming decades. Even if a miracle happened and we stopped all human emissions today, current GHGs in the atmosphere will keep trapping more heat for some decades. This is known as climate inertia or climate lag. Another aspect I don't see frequently mentioned are feedbacks. Again, even if we stopped all emissions today, self sustaining climatic systems will keep adding more heat to the atmosphere (methane, etc) or the sea (Arctic ice melting). We're currently at aprox 36 billion tonnes of carbon emissions per year [1] only counting fuel burning. It would be a miracle if we could even reach 50% of that in our lifetime, which was aprox the emissions from the 70s. [1] https://ourworldindata.org/co2-emissions https://ourworldindata.org/co2-emissions

knuthsat 5y ago
yeah, the n-th order effects like the siberian ice melting away into methane emissions equivalent to 100 years of 2020 CO2 output will just completely obliterate any efforts at mitigating new emissions.
- spacemark 5y ago
  ...if it happens. So far there's no scientific consensus that such a thing is likely to happen.
  - carlmr 5y ago
    The problem with these events is that we should err on the side of caution, since the other side may well be catastrophic.
    - spacemark 5y ago
      That's not good risk analysis. Severity is one axis, likelihood of occurring is another.
      - carlmr 5y ago
        Which is exactly my point. If something is 100x as bad as the alternative and "only" 10% likely, that's still a very high ~10x expectation of badness.
  - maxlamb 5y ago
    Isn’t it already happening? https://earther.gizmodo.com/methane-is-blowing-more-holes-in-the-arctic-1846242991 https://earther.gizmodo.com/methane-is-blowing-more-holes-in...
    - spacemark 5y ago
      That article doesn't say anything about how much methane is being released. The fact that it's happening isn't being disputed. The prediction that it will be catastrophic is.
      - titzer 5y ago
        Oh, it will absolutely be catastrophic if the Siberian tundra thaws. Have you seen the estimates for how much carbon is locked in the permafrost? It's more carbon than is in the atmosphere today. [1] [1] https://nsidc.org/cryosphere/frozenground/methane.html https://nsidc.org/cryosphere/frozenground/methane.html
      - maxlamb 5y ago
        17 million tons of methane in 2013 and rapidly increasing. Source: https://en.m.wikipedia.org/wiki/Arctic_methane_emissions https://en.m.wikipedia.org/wiki/Arctic_methane_emissions
        AnimalMuppet 5y ago
        So, is that a lot or a little? How much do cows produce? How much does human activity release? (Honest question; I don't know.)
        knuthsat 5y ago
        It's estimated there's 1300G tons of methane stored in tundra. 1300 * 10^9 is about 100 years of 2020 CO2 activity. 13 * 10^6 is 100/1000 years of 2020 CO2 activity, I guess.
  - titzer 5y ago
    > ...if it happens. Did you mean to write "if it keeps speeding up"? Because it is most definitely happening, it is speeding up [1], and it doesn't look likely to slow down. [1] https://earthobservatory.nasa.gov/images/146978/methane-emissions-continue-to-rise https://earthobservatory.nasa.gov/images/146978/methane-emis...
    - spacemark 5y ago
      The fact that it's happening isn't being disputed. The prediction that it will be catastrophic is. The NASA article you linked is reputable, but pay attention to what it actually says - it makes no predictions of impact severity. What the article DOES say: methane is responsible for 1/4 of all global warming, it's increased 9% in the last decade, and 250% in the last 17 decades (avg 15%/year).
titzer 5y ago
It looks bleak. There are fewer and fewer options remaining. Carbon sequestration at the source of emissions could reduce some CO2 from big fossil fuel power stations, but won't fix vehicles. We need a miracle technology that can actually extract CO2 from the air. Planting 1 trillion trees might help, but we won't do it.
- pier25 5y ago
  Fusion could be the miracle we need to kickstart strong negative emissions.
  - mywittyname 5y ago
    We've been trying to get design effective fusion reactors for what, like 50 years now? I wouldn't put much stock in that option.
    - elevaet 5y ago
      Just need another 20 years!
    - ben_w 5y ago
      Fusion research hasn’t ever been funded well enough to hit the various timelines. If people fund it, or if computing power gets cheap enough to solve the remaining research problems in-silico rather than with a demo reactor, we could plausibly get it in 5-10 years. But I agree with @gnfargbl, we should use the naturally occurring one that we orbit.
      - mywittyname 5y ago
        The issue is a lack of designs with promising commercial application. The world has dumped plenty of money into fusion design research since the 50s but only very recently created a design that could actually generate more power than it consumes containing the plasma field. The current most effective designs output 1.25w for every watt of input. And only at a very small scale. It's great that we can finally produce net energy from fusion. But let's not get ahead ourselves here. The issue is not funding, it's lack of brain power. Fusion is an insanely difficult nut to crack and trillions of dollars won't do crack it alone.
elbasti 5y ago
And a quick reminder that the IPCC reports/estimates excluded arctic methane emissions...which we a) now know are definitely happening and b) are just catastrophic positive feedback loops. The gun seems to have been fired.
- pier25 5y ago
  Indeed. Hopefully that will change for the next report coming in 2022.
- spacemark 5y ago
  Can you link to some sources on point B? From what I've read you'll find broad scientific consensus on your point A but your point B is not even close to widely accepted among climate scientists. That said I've learned the science can change rapidly, so I'm all ears if the position of the majority of climate scientists has shifted.
  - pier25 5y ago
    Not sure what you mean by "catastrophic" but for example last year some parts of Siberia had +5ºC on average during summer. https://www.theguardian.com/environment/2020/jul/15/climate-change-made-siberian-heatwave-600-times-more-likely-study https://www.theguardian.com/environment/2020/jul/15/climate-... This is not new and is getting worse. In 2010, Russian wildfires severely impacted the worldwide price of grain which (some people argue) helped trigger the Arab spring revolts. https://en.wikipedia.org/wiki/2010_Russian_wildfires https://en.wikipedia.org/wiki/2010_Russian_wildfires https://www.americanprogress.org/issues/security/reports/2013/02/28/54579/the-arab-spring-and-climate-change/ https://www.americanprogress.org/issues/security/reports/201...
ErikVandeWater 5y ago
There is also the negative feedback of plants growing faster due to increased available CO2 for them to use. It would be interesting to see the list of all feedbacks and estimated significance. There's also the wildcard of algae evolution. Since there are quadrillions of them, evolution happens very quickly so changes in ocean acidification and temperature could substantially change how efficiently they work. They could get better or worse.
- odnes 5y ago
  Do you have and references on your last point about algae? I have this (totally unsubstantiated) idea that plundering the oceans of fish along with rising temperatures will result in the oceans sequestering incredible amounts of CO2 via algae blooms. Never found much to read on the topic though - in what ways could this be negative feedback loop?

by pier25 5y ago

knuthsat 5y ago

yeah, the n-th order effects like the siberian ice melting away into methane emissions equivalent to 100 years of 2020 CO2 output will just completely obliterate any efforts at mitigating new emissions.

spacemark 5y ago
...if it happens. So far there's no scientific consensus that such a thing is likely to happen.
- carlmr 5y ago
  The problem with these events is that we should err on the side of caution, since the other side may well be catastrophic.
  - spacemark 5y ago
    That's not good risk analysis. Severity is one axis, likelihood of occurring is another.
    - carlmr 5y ago
      Which is exactly my point. If something is 100x as bad as the alternative and "only" 10% likely, that's still a very high ~10x expectation of badness.
- maxlamb 5y ago
  Isn’t it already happening? https://earther.gizmodo.com/methane-is-blowing-more-holes-in-the-arctic-1846242991 https://earther.gizmodo.com/methane-is-blowing-more-holes-in...
  - spacemark 5y ago
    That article doesn't say anything about how much methane is being released. The fact that it's happening isn't being disputed. The prediction that it will be catastrophic is.
    - titzer 5y ago
      Oh, it will absolutely be catastrophic if the Siberian tundra thaws. Have you seen the estimates for how much carbon is locked in the permafrost? It's more carbon than is in the atmosphere today. [1] [1] https://nsidc.org/cryosphere/frozenground/methane.html https://nsidc.org/cryosphere/frozenground/methane.html
    - maxlamb 5y ago
      17 million tons of methane in 2013 and rapidly increasing. Source: https://en.m.wikipedia.org/wiki/Arctic_methane_emissions https://en.m.wikipedia.org/wiki/Arctic_methane_emissions
      - AnimalMuppet 5y ago
        So, is that a lot or a little? How much do cows produce? How much does human activity release? (Honest question; I don't know.)
        knuthsat 5y ago
        It's estimated there's 1300G tons of methane stored in tundra. 1300 * 10^9 is about 100 years of 2020 CO2 activity. 13 * 10^6 is 100/1000 years of 2020 CO2 activity, I guess.
- titzer 5y ago
  > ...if it happens. Did you mean to write "if it keeps speeding up"? Because it is most definitely happening, it is speeding up [1], and it doesn't look likely to slow down. [1] https://earthobservatory.nasa.gov/images/146978/methane-emissions-continue-to-rise https://earthobservatory.nasa.gov/images/146978/methane-emis...
  - spacemark 5y ago
    The fact that it's happening isn't being disputed. The prediction that it will be catastrophic is. The NASA article you linked is reputable, but pay attention to what it actually says - it makes no predictions of impact severity. What the article DOES say: methane is responsible for 1/4 of all global warming, it's increased 9% in the last decade, and 250% in the last 17 decades (avg 15%/year).

titzer 5y ago

It looks bleak. There are fewer and fewer options remaining. Carbon sequestration at the source of emissions could reduce some CO2 from big fossil fuel power stations, but won't fix vehicles. We need a miracle technology that can actually extract CO2 from the air. Planting 1 trillion trees might help, but we won't do it.

pier25 5y ago
Fusion could be the miracle we need to kickstart strong negative emissions.
- mywittyname 5y ago
  We've been trying to get design effective fusion reactors for what, like 50 years now? I wouldn't put much stock in that option.
  - elevaet 5y ago
    Just need another 20 years!
  - ben_w 5y ago
    Fusion research hasn’t ever been funded well enough to hit the various timelines. If people fund it, or if computing power gets cheap enough to solve the remaining research problems in-silico rather than with a demo reactor, we could plausibly get it in 5-10 years. But I agree with @gnfargbl, we should use the naturally occurring one that we orbit.
    - mywittyname 5y ago
      The issue is a lack of designs with promising commercial application. The world has dumped plenty of money into fusion design research since the 50s but only very recently created a design that could actually generate more power than it consumes containing the plasma field. The current most effective designs output 1.25w for every watt of input. And only at a very small scale. It's great that we can finally produce net energy from fusion. But let's not get ahead ourselves here. The issue is not funding, it's lack of brain power. Fusion is an insanely difficult nut to crack and trillions of dollars won't do crack it alone.

elbasti 5y ago

And a quick reminder that the IPCC reports/estimates excluded arctic methane emissions...which we a) now know are definitely happening and b) are just catastrophic positive feedback loops. The gun seems to have been fired.

pier25 5y ago
Indeed. Hopefully that will change for the next report coming in 2022.
spacemark 5y ago
Can you link to some sources on point B? From what I've read you'll find broad scientific consensus on your point A but your point B is not even close to widely accepted among climate scientists. That said I've learned the science can change rapidly, so I'm all ears if the position of the majority of climate scientists has shifted.
- pier25 5y ago
  Not sure what you mean by "catastrophic" but for example last year some parts of Siberia had +5ºC on average during summer. https://www.theguardian.com/environment/2020/jul/15/climate-change-made-siberian-heatwave-600-times-more-likely-study https://www.theguardian.com/environment/2020/jul/15/climate-... This is not new and is getting worse. In 2010, Russian wildfires severely impacted the worldwide price of grain which (some people argue) helped trigger the Arab spring revolts. https://en.wikipedia.org/wiki/2010_Russian_wildfires https://en.wikipedia.org/wiki/2010_Russian_wildfires https://www.americanprogress.org/issues/security/reports/2013/02/28/54579/the-arab-spring-and-climate-change/ https://www.americanprogress.org/issues/security/reports/201...

ErikVandeWater 5y ago

There is also the negative feedback of plants growing faster due to increased available CO2 for them to use. It would be interesting to see the list of all feedbacks and estimated significance. There's also the wildcard of algae evolution. Since there are quadrillions of them, evolution happens very quickly so changes in ocean acidification and temperature could substantially change how efficiently they work. They could get better or worse.

odnes 5y ago
Do you have and references on your last point about algae? I have this (totally unsubstantiated) idea that plundering the oceans of fish along with rising temperatures will result in the oceans sequestering incredible amounts of CO2 via algae blooms. Never found much to read on the topic though - in what ways could this be negative feedback loop?