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So if the earth heats up, and more water evaporates, and more clouds form to block the sun, will this lead to a global cooling effect? My understanding is this

by yters 9y ago

So if the earth heats up, and more water evaporates, and more clouds form to block the sun, will this lead to a global cooling effect? My understanding is this was the old worry, that all our pollutants were going to block out the sun and lead to a new ice age, or at least the Matrix.

KnightOfWords 9y ago
Clouds reflect sunlight but they also trap heat, by absorbing infrared radiation and re-emitting it. (In Winter, notice how much colder it is in the morning when it's been clear all night.)
- yters 9y ago
  So if I lived in a country that is always cloudy it will be warmer than a country that is never cloudy?
bigbugbag 9y ago
There is a positive feedback loop, more water vapor in the athmosphere double the CO2 greenhouse effect, and factoring in other feedback loops we get over 3 times more greenhouse effect, which warms the earth and increase water vapor in the athmosphere, etc. This process could lead to oceans boiling out (though not on Earth, but it may be the case for Venus).
- yters 9y ago
  If it could go either way, why are we so sure it is an unstable loop in one particular direction? Our world used to be much warmer than it is now, yet somehow it cooled down a whole lot. There are just not enough lines connecting all the dots here.
  - bigbugbag 9y ago
    I don't know what an unstable loop is. I was referring to the well defined cybernetics concept of feedback loop[1] which is simple: a feedback loop occurs when the output of a system applies to the input of the system. In the discussed case it is a positive feedback loop as outputs adds itself to input [2]. I don't understand what you are trying to say by pointing out earth was warmer and cooled down, but you can read about positive and negative feedback loop during glacial period on wikipedia[3]. [1]: https://en.wikipedia.org/wiki/Feedback#/media/File:General_Feedback_Loop.svg https://en.wikipedia.org/wiki/Feedback#/media/File:General_F... [2]: https://www.annualreviews.org/doi/full/10.1146/annurev.energy.25.1.441 https://www.annualreviews.org/doi/full/10.1146/annurev.energ... [3]: https://en.wikipedia.org/wiki/Ice_age#Positive_and_negative_feedback_in_glacial_periods https://en.wikipedia.org/wiki/Ice_age#Positive_and_negative_...

by yters 9y ago

KnightOfWords 9y ago

Clouds reflect sunlight but they also trap heat, by absorbing infrared radiation and re-emitting it. (In Winter, notice how much colder it is in the morning when it's been clear all night.)

yters 9y ago
So if I lived in a country that is always cloudy it will be warmer than a country that is never cloudy?

bigbugbag 9y ago

There is a positive feedback loop, more water vapor in the athmosphere double the CO2 greenhouse effect, and factoring in other feedback loops we get over 3 times more greenhouse effect, which warms the earth and increase water vapor in the athmosphere, etc. This process could lead to oceans boiling out (though not on Earth, but it may be the case for Venus).

yters 9y ago
If it could go either way, why are we so sure it is an unstable loop in one particular direction? Our world used to be much warmer than it is now, yet somehow it cooled down a whole lot. There are just not enough lines connecting all the dots here.
- bigbugbag 9y ago
  I don't know what an unstable loop is. I was referring to the well defined cybernetics concept of feedback loop[1] which is simple: a feedback loop occurs when the output of a system applies to the input of the system. In the discussed case it is a positive feedback loop as outputs adds itself to input [2]. I don't understand what you are trying to say by pointing out earth was warmer and cooled down, but you can read about positive and negative feedback loop during glacial period on wikipedia[3]. [1]: https://en.wikipedia.org/wiki/Feedback#/media/File:General_Feedback_Loop.svg https://en.wikipedia.org/wiki/Feedback#/media/File:General_F... [2]: https://www.annualreviews.org/doi/full/10.1146/annurev.energy.25.1.441 https://www.annualreviews.org/doi/full/10.1146/annurev.energ... [3]: https://en.wikipedia.org/wiki/Ice_age#Positive_and_negative_feedback_in_glacial_periods https://en.wikipedia.org/wiki/Ice_age#Positive_and_negative_...