4 ms·

I can't find it either. I only see gigatonnes. Even with a naive calculation that assumes no ice reclaimed elsewhere, I get 1.8mm. https://docs.google.com/sprea

I can't find it either. I only see gigatonnes. Even with a naive calculation that assumes no ice reclaimed elsewhere, I get 1.8mm. https://docs.google.com/spreadsheets/d/1zC2c30kIkbx39v0gyY1PrPJEFJW4LBMkYxW_RbdcKYc/edit#gid=0 https://docs.google.com/spreadsheets/d/1zC2c30kIkbx39v0gyY1P...

Arnt 7y ago
Why is that naïve?
- brlewis 7y ago
  Because in the opposite hemisphere, water is turning to snow and ice.
  - Arnt 7y ago
    I see, good point. However, it seems insignificant, since that process happens relative to the surface of the ocean, not to the bottom of the ocean. Assume that the top 1cm of sea water in the southern hemisphere evaporates, turns to clouds, and lands on Antarctica in the form of snow. If that top 1cm of the ocean is 2.2mm (or 1.8mm) further from the ocean bottom, I don't see why that would increase (or decrease) evaporation.
    - misja111 7y ago
      The source of the article does mention Antarctica: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL087291 https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020... "In Antarctica, ongoing high mass losses in the Amundsen Sea Embayment of West Antarctica, the Antarctic Peninsula, and Wilkes Land in East Antarctica cumulate to 2130, 560, and 370 Gigatonnes, respectively, since 2002. A cumulative mass gain of 980 Gigatonnes in Queen Maud Land since 2009, however, led to a pause in the acceleration in mass loss from Antarctica after 2016."
      - Arnt 7y ago
        Sure, Antarctica affects sea level even if it doesn't affect brlewis' computation. My point is just that brlewis' arithmetic doesn't seem naïve.
  - bregma 7y ago
    The ocean freezing anywhere is irrelevant: the mass of water in the ocean stays the same regardless of its phase. The problem discussed here is the Greenlad ice cap melting, which we can assume increases the mass of water in the ocean. The nature of ice caps in both Greenland and Antarctica is that they are in deserts that go for years with zero precipitation. Ice accumulates steadily through what we can think of as layers of frost every morning over centuries until it covers entire continents kilometers deep. On the other hand, surface melt due to increased seasonal insolation usually doesn't result in much runoff: these are not glaciers that slowly flow out to sea, either.
    - brlewis 7y ago
      Just to make sure the context is clear, my main question is why the article headline says this particular melt caused a 2.2mm global rise in sea level. The melting described in the article would only account for a 1.8mm rise, in isolation. If anything happening in Antarctica had an effect, it would lower that number even further, making it more different from the headline. Does the 2.2mm number include other melting that the article and cited paper don't mention?

Arnt 7y ago

Why is that naïve?

brlewis 7y ago
Because in the opposite hemisphere, water is turning to snow and ice.
- Arnt 7y ago
  I see, good point. However, it seems insignificant, since that process happens relative to the surface of the ocean, not to the bottom of the ocean. Assume that the top 1cm of sea water in the southern hemisphere evaporates, turns to clouds, and lands on Antarctica in the form of snow. If that top 1cm of the ocean is 2.2mm (or 1.8mm) further from the ocean bottom, I don't see why that would increase (or decrease) evaporation.
  - misja111 7y ago
    The source of the article does mention Antarctica: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL087291 https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020... "In Antarctica, ongoing high mass losses in the Amundsen Sea Embayment of West Antarctica, the Antarctic Peninsula, and Wilkes Land in East Antarctica cumulate to 2130, 560, and 370 Gigatonnes, respectively, since 2002. A cumulative mass gain of 980 Gigatonnes in Queen Maud Land since 2009, however, led to a pause in the acceleration in mass loss from Antarctica after 2016."
    - Arnt 7y ago
      Sure, Antarctica affects sea level even if it doesn't affect brlewis' computation. My point is just that brlewis' arithmetic doesn't seem naïve.
- bregma 7y ago
  The ocean freezing anywhere is irrelevant: the mass of water in the ocean stays the same regardless of its phase. The problem discussed here is the Greenlad ice cap melting, which we can assume increases the mass of water in the ocean. The nature of ice caps in both Greenland and Antarctica is that they are in deserts that go for years with zero precipitation. Ice accumulates steadily through what we can think of as layers of frost every morning over centuries until it covers entire continents kilometers deep. On the other hand, surface melt due to increased seasonal insolation usually doesn't result in much runoff: these are not glaciers that slowly flow out to sea, either.
  - brlewis 7y ago
    Just to make sure the context is clear, my main question is why the article headline says this particular melt caused a 2.2mm global rise in sea level. The melting described in the article would only account for a 1.8mm rise, in isolation. If anything happening in Antarctica had an effect, it would lower that number even further, making it more different from the headline. Does the 2.2mm number include other melting that the article and cited paper don't mention?