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Sure, pumping enough aerosols into the atmosphere will stop nearly instantly global warming. And it opens a path to burn even more carbon. But whom would you tr

by noiv 14y ago

Sure, pumping enough aerosols into the atmosphere will stop nearly instantly global warming. And it opens a path to burn even more carbon. But whom would you trust to run this solution over the next millions of years until all carbon is back in Earth's crust? The point is, if it stops working all hidden and accumulated warming will kick in virtually over night. And nobody wants the planet to warm by 4°C within days.

aroberge 14y ago
While I do not advocate to messing up with the atmosphere, your statement shows a clear lack of understanding. Carbon being trapped is NOT the same as heat being trapped in the earth's crust. The Earth could NOT warm by 4°C within days - that is ludicrous. Here's the deal: the Earth is warmed by the Sun; it cools off by emitting back (glowing in the infra-red region if you wish) some of the heat. An equilibrium is reached when the amount of energy emitted is equal to the amount it receives. (Thus, Mars is cooler than the Earth which is cooler than Venus...). The amount of energy that can be emitted back into space depends on the property of the atmosphere. Some gas (so-called greenhouse gas) will prevent energy (in the form of infra-red radiation) from escaping, thus contributing to the rise of the temperature, until a new equilibrium is reached. (The proposed solution is to change the atmosphere properties so that less energy reaches the Earth in the first place.) We are currently seeing such a heating taking place, and it is not happening "within days".
- noiv 14y ago
  You did not get the point. Currently we are close to 400ppm/+0.8°C without geo-engineering. If we use geo-engineering, keep temperature at current level and continue emitting CO2 to let's say 1000ppm, we can't stop because the greenhouse effect of these extra 600ppm will kick in as fast as the reducing effect of the engineering slows down. But you are right: This is not comparable to today's situation where concentration rises by 1-2 ppm y⁻¹, but it is comparable to injecting instantly the equivalent of 600ppm into the atmosphere. It's like the opposite of a huge volcano eruption. So to make a long story short, any geo-engineering solution which does not remove greenhouse gases from the atmosphere and turn them into a stable chemical compound is nothing but a time bomb - exploding at failure.
  - aroberge 14y ago
    Yes, I did get the point, but I don't believe that you get the Physics. It takes a lot of energy to raise the average temperature of the earth by 4 C - much more than we are getting from the Sun "within a few days". Stopping (most) of the Sun's light to reach the Earth would be an effective (if not crazy...) way of cooling down the Earth. Adding a huge quantity of greenhouse gases is not going to turn the atmosphere into a one-way trap for radiation. The physics involved in light being blocked by air-borne aerosol particles and that of the trapping of heat by greenhouse gases are different, and their effect, while going in opposite direction, are not the exact inverse one of another.
    - noiv 14y ago
      Would you prefer to read 'weeks'?
      - aroberge 14y ago
        No, I would prefer at least "years", but even better "decades". A few days (or weeks depending on your background) is the time required to read a few papers on the Physics of the atmosphere.

by noiv 14y ago

aroberge 14y ago

While I do not advocate to messing up with the atmosphere, your statement shows a clear lack of understanding. Carbon being trapped is NOT the same as heat being trapped in the earth's crust. The Earth could NOT warm by 4°C within days - that is ludicrous. Here's the deal: the Earth is warmed by the Sun; it cools off by emitting back (glowing in the infra-red region if you wish) some of the heat. An equilibrium is reached when the amount of energy emitted is equal to the amount it receives. (Thus, Mars is cooler than the Earth which is cooler than Venus...). The amount of energy that can be emitted back into space depends on the property of the atmosphere. Some gas (so-called greenhouse gas) will prevent energy (in the form of infra-red radiation) from escaping, thus contributing to the rise of the temperature, until a new equilibrium is reached. (The proposed solution is to change the atmosphere properties so that less energy reaches the Earth in the first place.) We are currently seeing such a heating taking place, and it is not happening "within days".

noiv 14y ago
You did not get the point. Currently we are close to 400ppm/+0.8°C without geo-engineering. If we use geo-engineering, keep temperature at current level and continue emitting CO2 to let's say 1000ppm, we can't stop because the greenhouse effect of these extra 600ppm will kick in as fast as the reducing effect of the engineering slows down. But you are right: This is not comparable to today's situation where concentration rises by 1-2 ppm y⁻¹, but it is comparable to injecting instantly the equivalent of 600ppm into the atmosphere. It's like the opposite of a huge volcano eruption. So to make a long story short, any geo-engineering solution which does not remove greenhouse gases from the atmosphere and turn them into a stable chemical compound is nothing but a time bomb - exploding at failure.
- aroberge 14y ago
  Yes, I did get the point, but I don't believe that you get the Physics. It takes a lot of energy to raise the average temperature of the earth by 4 C - much more than we are getting from the Sun "within a few days". Stopping (most) of the Sun's light to reach the Earth would be an effective (if not crazy...) way of cooling down the Earth. Adding a huge quantity of greenhouse gases is not going to turn the atmosphere into a one-way trap for radiation. The physics involved in light being blocked by air-borne aerosol particles and that of the trapping of heat by greenhouse gases are different, and their effect, while going in opposite direction, are not the exact inverse one of another.
  - noiv 14y ago
    Would you prefer to read 'weeks'?
    - aroberge 14y ago
      No, I would prefer at least "years", but even better "decades". A few days (or weeks depending on your background) is the time required to read a few papers on the Physics of the atmosphere.