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Adding a ton of water to the atmosphere is going to cause more warming. Water vapour is Earth's most abundant greenhouse gas. It's responsible for about half of

Adding a ton of water to the atmosphere is going to cause more warming. Water vapour is Earth's most abundant greenhouse gas. It's responsible for about half of Earth's greenhouse effect.

lproven 3y ago
It is vital to consider proportion: 2/3 of the Earth is ocean. These new seas would be absolutely tiny by comparison. The extra water vapour added to the atmosphere would be a rounding error. Unfortunately the same applies to the amount of sea level rise they offset: it too would be a rounding error, a fraction of a percent.
- lostlogin 3y ago
  > Unfortunately the same applies to the amount of sea level rise they offset: it too would be a rounding error, a fraction of a percent. Flooding Flood the Qattara Depression would lower the sea level by 3mm according to the article.
  - lproven 3y ago
    Yes... which is less than the current annual increase of 3.4mm: https://sealevel.nasa.gov/faq/8/is-the-rate-of-sea-level-rise-increasing/ https://sealevel.nasa.gov/faq/8/is-the-rate-of-sea-level-ris... The West Anarctic Ice Sheet alone will cause ~3.3m rise when it collapses. https://www.carbonbrief.org/guest-post-how-close-is-the-west-antarctic-ice-sheet-to-a-tipping-point/ https://www.carbonbrief.org/guest-post-how-close-is-the-west... Note, NOT melts; just when it breaks up and floats away, still frozen. That one ice sheet, currently cracking, is over half resting on rock that is way below sea level. Some is 2000m under sea level. It doesn't need to melt, it just needs to break off and float away. That would cause a 3.5-5m *depending on ow much floated) increase in mean sea level, worldwide, in approximately 12 days. That is over 1000x time the reduction caused by flooding the Qattara depression. Or 0.1% -- or as I said, a fraction of a per cent.
keyle 3y ago
Unlikely to be important, compared to the creation of irrigation and additional plants and greenery that generates O2 and absorbs CO2?
throwaway290 3y ago
Before someone reading this thinks that drying up the planet would cool it down: water in the air acts as a greenhouse gas, but also cools the surface when it evaporates and helps reflect solar radiation when it forms clouds (major factor of our planet's albedo). Also we are not comparing more water area vs less water area. Water will take more area in any case as sea levels rise. This way it just happens in a bit more controlled way.
jonstewart 3y ago
It all depends on clouds, though.
- patall 3y ago
  It's always astonishing to me how pretty much every climatologist will tell you "clounds are the joker". It totally makes sense, but that doesn't make it in any way less fascinating and is kind of funny.
luxcem 3y ago
Adding water to the atmosphere does not cause more warming due to greenhouse effect at least not on this scale. Water vapor concentration is regulated by condensation, adding more water simply means more rain. What is actually causing more warming is the increase of temperature, that changes the equilibrium vapor pressure point.

Adding a ton of water to the atmosphere is going to cause more warming. Water vapour is Earth's most abundant greenhouse gas. It's responsible for about half of Earth's greenhouse effect.

lproven 3y ago

It is vital to consider proportion: 2/3 of the Earth is ocean. These new seas would be absolutely tiny by comparison. The extra water vapour added to the atmosphere would be a rounding error. Unfortunately the same applies to the amount of sea level rise they offset: it too would be a rounding error, a fraction of a percent.

lostlogin 3y ago
> Unfortunately the same applies to the amount of sea level rise they offset: it too would be a rounding error, a fraction of a percent. Flooding Flood the Qattara Depression would lower the sea level by 3mm according to the article.
- lproven 3y ago
  Yes... which is less than the current annual increase of 3.4mm: https://sealevel.nasa.gov/faq/8/is-the-rate-of-sea-level-rise-increasing/ https://sealevel.nasa.gov/faq/8/is-the-rate-of-sea-level-ris... The West Anarctic Ice Sheet alone will cause ~3.3m rise when it collapses. https://www.carbonbrief.org/guest-post-how-close-is-the-west-antarctic-ice-sheet-to-a-tipping-point/ https://www.carbonbrief.org/guest-post-how-close-is-the-west... Note, NOT melts; just when it breaks up and floats away, still frozen. That one ice sheet, currently cracking, is over half resting on rock that is way below sea level. Some is 2000m under sea level. It doesn't need to melt, it just needs to break off and float away. That would cause a 3.5-5m *depending on ow much floated) increase in mean sea level, worldwide, in approximately 12 days. That is over 1000x time the reduction caused by flooding the Qattara depression. Or 0.1% -- or as I said, a fraction of a per cent.

keyle 3y ago

Unlikely to be important, compared to the creation of irrigation and additional plants and greenery that generates O2 and absorbs CO2?

throwaway290 3y ago

Before someone reading this thinks that drying up the planet would cool it down: water in the air acts as a greenhouse gas, but also cools the surface when it evaporates and helps reflect solar radiation when it forms clouds (major factor of our planet's albedo). Also we are not comparing more water area vs less water area. Water will take more area in any case as sea levels rise. This way it just happens in a bit more controlled way.

jonstewart 3y ago

It all depends on clouds, though.

patall 3y ago
It's always astonishing to me how pretty much every climatologist will tell you "clounds are the joker". It totally makes sense, but that doesn't make it in any way less fascinating and is kind of funny.

luxcem 3y ago

Adding water to the atmosphere does not cause more warming due to greenhouse effect at least not on this scale. Water vapor concentration is regulated by condensation, adding more water simply means more rain. What is actually causing more warming is the increase of temperature, that changes the equilibrium vapor pressure point.