3 ms·

So far it's the first confirmed case of negative feedback from global warming that I've seen, and that makes me hopeful.

johnnyApplePRNG 5y ago
Another one is smoke from forest fires; actively cooling the planet.
- voisin 5y ago
  Have you come across any quantification of this?
  - Salgat 5y ago
    Great question. We know that a large enough volcano eruption can cause a year long winter so I'm curious how much large scale forest fires can compare. Also, assuming regrowth is allowed, the CO2 impact from the burned wood is neutral in the long run.
  - prewett 5y ago
    This is anecdotal quantification, but I lived in northern California for a few years and late June would usually be in the 100s or 110s. By August when California catches on fire, it cools down to 90s (when the smoke was blowing our way). By contrast, when I lived in Texas (no fires), June and July would be in the low 100s, and the first two weeks of August would be 107 - 112.
  - johnnyApplePRNG 5y ago
    No. Entirely anecdotal and of my own observance. I traveled from Ontario to British Columbia two years ago when the forest fires out west were really peaking. I noticed smoke in the air as far as Winnipeg, and it only got thicker as I approached Vancouver. Surely all of those white/reflective particles in the upper atmosphere are reflecting the sun's rays. Also, weather predictions that year where WAY off. Predictions were always much higher than the actual high of the day. I assume this is resultant from historical weather data being a poor source for an altered state weather season. The smoke covered almost all of north america at some points and it really got much cooler than seasonal averages.
  - plank_time 5y ago
    Back in the early 90s a volcano erupted in the Philippines. In Canada where I grew up, late that summer in August, it was below freezing in the mornings. I had never encountered that before and was a direct result of the volcano.
  - pvaldes 5y ago
    Is public knowledge than most smoke in wildfires is water. If we see white smoke, is water vapor (mostly). Unlike volcanoes, any temporary cold effect from clouds would be negated by the permanent destruction of the forest.
- logicfiction 5y ago
  Is it really a negative feedback and not just transient though? Sure it may cool things during the fire, but it also just destroyed some carbon sinks and worsened the overall emissions effect. Then the fire ends and it no longer has any cooling effect so its not feeding back.
stupendousyappi 5y ago
There are several others. I'm not a climate scientist, but my understanding is that the most significant potential negative feedback loop by far is the potential for increased cloud cover from increased humidity. It's evidently the most difficult aspect of global warming to model, although climate scientists are making continuous progress. In addition, the marginal radiative forcing of CO2 decreases with its concentration, which means both that increases in emissions do less harm as things get worse, and that reductions in emissions do less good.
- raducu 5y ago
  So, when is this negative feedback loop supposed to kick in and save us from global warming and climate change?
  - ncmncm 5y ago
    It is already "kicked in", and all figured in, is not saving us, and will not save us.
flavius29663 5y ago
Global warming means more water in the air. This is both a positive feedback (water is an excellent heat trap) and negative in the form of clouds. White clouds increase the albedo of the planet, rejecting heat. Another negative feedback is the increased intake of CO2 by oceans, through difussion. Also the plankton consumes more CO2. It makes sense, think about it: if the planet didn't have negative feedbacks, absolutely any event would potentially cause a runoff through positive feedback in warmings and throw the climate out of balance. Even something like a vulcanic eruption or forest fire in the middle ages: without the negative feedback, CO2 would cause warming, which causes more water, which causes warming...there must be some serious negative feedback loops, which is why we've almost doubled the warming effect of CO2 with (so far) very small influences on the climate.
- raducu 5y ago
  Well, everything has negative feedback loops, otherwise the universe would exoerience a second Big Bang, right? But is that statement reasurring in any way? No, because in between the limits of those feedback loops there's enormous potential for devastation and human suffering.
  - flavius29663 5y ago
    It's reassuring in the sense that I believe there is a very slim chance of runaway warming based on positive feedback loop. These levels of CO2 are pretty low on a geological scale, increases to 400-800ppm CO2 have not caused a runaway global warming a la Venus ever before. More of the Earh's life as a living planet was spent above 1000 ppm than under. https://www.researchgate.net/profile/Henning-Haeupler/publication/325078712/figure/fig17/AS:625014961344528@1526026587793/Global-temperature-and-atmospheric-CO2-over-geological-time-600-mya-Aus-from-HIEB.png https://www.researchgate.net/profile/Henning-Haeupler/public... In fact, there was a period in the past when the Earth warmed 10 degree Celsius (18 F) in 10 years, and there was no runaway global warming. There will be warming, there will be positive and negative feedbacks, we don't know for sure how big each will be. The true pity is that we're in the midst of a mass extinction event. Between pollution, loss of habitat and rapid warming - we're killing off species like we're a killer meteor...and there's no coming back for the Amazon rain-forest and countless species. Once they're gone they're gone.

johnnyApplePRNG 5y ago

Another one is smoke from forest fires; actively cooling the planet.

voisin 5y ago
Have you come across any quantification of this?
- Salgat 5y ago
  Great question. We know that a large enough volcano eruption can cause a year long winter so I'm curious how much large scale forest fires can compare. Also, assuming regrowth is allowed, the CO2 impact from the burned wood is neutral in the long run.
- prewett 5y ago
  This is anecdotal quantification, but I lived in northern California for a few years and late June would usually be in the 100s or 110s. By August when California catches on fire, it cools down to 90s (when the smoke was blowing our way). By contrast, when I lived in Texas (no fires), June and July would be in the low 100s, and the first two weeks of August would be 107 - 112.
- johnnyApplePRNG 5y ago
  No. Entirely anecdotal and of my own observance. I traveled from Ontario to British Columbia two years ago when the forest fires out west were really peaking. I noticed smoke in the air as far as Winnipeg, and it only got thicker as I approached Vancouver. Surely all of those white/reflective particles in the upper atmosphere are reflecting the sun's rays. Also, weather predictions that year where WAY off. Predictions were always much higher than the actual high of the day. I assume this is resultant from historical weather data being a poor source for an altered state weather season. The smoke covered almost all of north america at some points and it really got much cooler than seasonal averages.
- plank_time 5y ago
  Back in the early 90s a volcano erupted in the Philippines. In Canada where I grew up, late that summer in August, it was below freezing in the mornings. I had never encountered that before and was a direct result of the volcano.
- pvaldes 5y ago
  Is public knowledge than most smoke in wildfires is water. If we see white smoke, is water vapor (mostly). Unlike volcanoes, any temporary cold effect from clouds would be negated by the permanent destruction of the forest.
logicfiction 5y ago
Is it really a negative feedback and not just transient though? Sure it may cool things during the fire, but it also just destroyed some carbon sinks and worsened the overall emissions effect. Then the fire ends and it no longer has any cooling effect so its not feeding back.

stupendousyappi 5y ago

There are several others. I'm not a climate scientist, but my understanding is that the most significant potential negative feedback loop by far is the potential for increased cloud cover from increased humidity. It's evidently the most difficult aspect of global warming to model, although climate scientists are making continuous progress. In addition, the marginal radiative forcing of CO2 decreases with its concentration, which means both that increases in emissions do less harm as things get worse, and that reductions in emissions do less good.

raducu 5y ago
So, when is this negative feedback loop supposed to kick in and save us from global warming and climate change?
- ncmncm 5y ago
  It is already "kicked in", and all figured in, is not saving us, and will not save us.

flavius29663 5y ago

Global warming means more water in the air. This is both a positive feedback (water is an excellent heat trap) and negative in the form of clouds. White clouds increase the albedo of the planet, rejecting heat. Another negative feedback is the increased intake of CO2 by oceans, through difussion. Also the plankton consumes more CO2. It makes sense, think about it: if the planet didn't have negative feedbacks, absolutely any event would potentially cause a runoff through positive feedback in warmings and throw the climate out of balance. Even something like a vulcanic eruption or forest fire in the middle ages: without the negative feedback, CO2 would cause warming, which causes more water, which causes warming...there must be some serious negative feedback loops, which is why we've almost doubled the warming effect of CO2 with (so far) very small influences on the climate.

raducu 5y ago
Well, everything has negative feedback loops, otherwise the universe would exoerience a second Big Bang, right? But is that statement reasurring in any way? No, because in between the limits of those feedback loops there's enormous potential for devastation and human suffering.
- flavius29663 5y ago
  It's reassuring in the sense that I believe there is a very slim chance of runaway warming based on positive feedback loop. These levels of CO2 are pretty low on a geological scale, increases to 400-800ppm CO2 have not caused a runaway global warming a la Venus ever before. More of the Earh's life as a living planet was spent above 1000 ppm than under. https://www.researchgate.net/profile/Henning-Haeupler/publication/325078712/figure/fig17/AS:625014961344528@1526026587793/Global-temperature-and-atmospheric-CO2-over-geological-time-600-mya-Aus-from-HIEB.png https://www.researchgate.net/profile/Henning-Haeupler/public... In fact, there was a period in the past when the Earth warmed 10 degree Celsius (18 F) in 10 years, and there was no runaway global warming. There will be warming, there will be positive and negative feedbacks, we don't know for sure how big each will be. The true pity is that we're in the midst of a mass extinction event. Between pollution, loss of habitat and rapid warming - we're killing off species like we're a killer meteor...and there's no coming back for the Amazon rain-forest and countless species. Once they're gone they're gone.