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Why on earth would anyone think a cooler but darker Earth is less of a catastrophic ecosystem change? This is so wrongheaded that I’m actually wondering if thi

Why on earth would anyone think a cooler but darker Earth is less of a catastrophic ecosystem change? This is so wrongheaded that I’m actually wondering if this story was pitched by some group that wants to smear geoengineering. I mean, geoengineering has a lot of ideas in it that are (while still out there) much less viscerally horrifying than blotting out the sun.

pfdietz 4y ago
It would be a slightly darker earth. The net warming from CO2 addition is a few watts/m^2. Insolation is something shy of two orders of magnitude higher. Dimming sunlight by a few percent is not a large change.
- SomeBoolshit 4y ago
  I'm gonna wait until we're sure about the effect on every living organism on earth.
  - pfdietz 4y ago
    Because that same standard is being applied to CO2 emission, right? What a double standard you have.
- AbrahamParangi 4y ago
  Why would you consider a few percent of sunlight change to be meaningless whereas a few degrees (a smaller percent, temp should be considered in Kelvin) is extremely meaningful?
  - pfdietz 4y ago
    Why should I not? I'm at a loss to understand why you think you're making a good argument there. There are far larger changes in insolation over the day and over seasons. Life is obviously less sensitive to these flucuations, than life would be to changes in temperature.
    - AbrahamParangi 4y ago
      Each argument is symmetrical! There are large fluctuations in temperature over space and time as well! Presuming that one matters and one doesn’t is making an assumption that needs to be proven at minimum, whereas the null hypothesis should be something like “it is not clear what changing the baseline temperature or light levels of an environment will do, but it’s probably bad for the ecosystem”.
      - pfdietz 4y ago
        The size of the fluctuation in insolation is very much larger than the change in temperature. One goes from 1000 W/m^2 in noon sun to, what, milliwatts/m^2 from starlight? Many orders of magnitude. Temperature goes from maybe 250K to 320K over the year, maybe, a change of maybe 30%?
beanjuice 4y ago
Not all sunlight is the same, and the majority of the heat comes from some of the lesser-utilized parts of that spectrum.
civilized 4y ago
> Why on earth would anyone think a cooler but darker Earth is less of a catastrophic ecosystem change? It seems possible to me, although definitely not certain. The worst consequence would be less photosynthesis and less food, but we have surplus food production capacity on Earth. And maybe even that could be avoided if the blocking happens mostly in the infrared regime that causes most of the heating. On our current path, we have areas of the Earth holding hundreds of millions of people which are projected to become too hot for human life for some of the year. Action that avoids that has something going for it, even if it also has downsides.

pfdietz 4y ago

It would be a slightly darker earth. The net warming from CO2 addition is a few watts/m^2. Insolation is something shy of two orders of magnitude higher. Dimming sunlight by a few percent is not a large change.

SomeBoolshit 4y ago
I'm gonna wait until we're sure about the effect on every living organism on earth.
- pfdietz 4y ago
  Because that same standard is being applied to CO2 emission, right? What a double standard you have.
AbrahamParangi 4y ago
Why would you consider a few percent of sunlight change to be meaningless whereas a few degrees (a smaller percent, temp should be considered in Kelvin) is extremely meaningful?
- pfdietz 4y ago
  Why should I not? I'm at a loss to understand why you think you're making a good argument there. There are far larger changes in insolation over the day and over seasons. Life is obviously less sensitive to these flucuations, than life would be to changes in temperature.
  - AbrahamParangi 4y ago
    Each argument is symmetrical! There are large fluctuations in temperature over space and time as well! Presuming that one matters and one doesn’t is making an assumption that needs to be proven at minimum, whereas the null hypothesis should be something like “it is not clear what changing the baseline temperature or light levels of an environment will do, but it’s probably bad for the ecosystem”.
    - pfdietz 4y ago
      The size of the fluctuation in insolation is very much larger than the change in temperature. One goes from 1000 W/m^2 in noon sun to, what, milliwatts/m^2 from starlight? Many orders of magnitude. Temperature goes from maybe 250K to 320K over the year, maybe, a change of maybe 30%?

beanjuice 4y ago

Not all sunlight is the same, and the majority of the heat comes from some of the lesser-utilized parts of that spectrum.

civilized 4y ago

> Why on earth would anyone think a cooler but darker Earth is less of a catastrophic ecosystem change? It seems possible to me, although definitely not certain. The worst consequence would be less photosynthesis and less food, but we have surplus food production capacity on Earth. And maybe even that could be avoided if the blocking happens mostly in the infrared regime that causes most of the heating. On our current path, we have areas of the Earth holding hundreds of millions of people which are projected to become too hot for human life for some of the year. Action that avoids that has something going for it, even if it also has downsides.