6 ms·

Certainly significant but that also happens on a massive time scale - the best estimates have us up 0.7 meters in 2100. https://www.noaa.gov/news-release/us-co

by jjcon 5y ago

Certainly significant but that also happens on a massive time scale - the best estimates have us up 0.7 meters in 2100. https://www.noaa.gov/news-release/us-coastline-to-see-up-to-foot-of-sea-level-rise-by-2050 https://www.noaa.gov/news-release/us-coastline-to-see-up-to-...

Gravityloss 5y ago
Unfortunately, that's just linear extrapolation from current rates. Ice sheet collapse can be extremely nonlinear, accelerating rapidly. https://www.nature.com/articles/s41467-018-05003-z.pdf?origin=ppub https://www.nature.com/articles/s41467-018-05003-z.pdf?origi... Or watch any of Eric Rignot's presentations in youtube. The term is Marine Ice Sheet Instability. This video in my opinion gives a fun demonstration of it https://www.youtube.com/watch?v=jLdaAKIkpKA https://www.youtube.com/watch?v=jLdaAKIkpKA Miscommunicating sea level rise risk is a big problem.
- jjcon 5y ago
  False, the long term NOAA models are far more complex than simple extrapolation (though that is of course a part of any forecast) and they certainly aren’t linear. Feel free to read up on them yourself: https://oceanservice.noaa.gov/hazards/sealevelrise/sealevelrise-tech-report-sections.html https://oceanservice.noaa.gov/hazards/sealevelrise/sealevelr...
  - Gravityloss 5y ago
    Thanks, I was wrong. The report is good reading.
    - wrycoder 5y ago
      But you must have seen something I didn’t. See my comment nearby.
  - wrycoder 5y ago
    > Global mean sea level, or the average height of the ocean surface, has risen 6 - 8 inches (15 - 20 centimeters) since 1920. In the continental U.S., relative sea level has risen about 10 - 12 inches (25 - 30 centimeters) over the same period. Observational data from tide gauges and satellites also show that sea level rise, both globally and along the continental U.S., is accelerating, with more than a third of that rise having occurred in the past two and a half decades (see NOAA and NASA portals for altimeter-based global rates and NOAA for local tide gauge rates). So, 30% of the normal one foot per century (somewhat less worldwide) happened in the last 25% of the time. That’s not a big acceleration, that’s measurement error. And yet this report says the rate of rise will nearly triple over the next thirty years. This is simply not plausible. Generally, the report reduced the predictions. Also, they eliminated the 2.5 meter (!) scenario.

by jjcon 5y ago

Gravityloss 5y ago

Unfortunately, that's just linear extrapolation from current rates. Ice sheet collapse can be extremely nonlinear, accelerating rapidly. https://www.nature.com/articles/s41467-018-05003-z.pdf?origin=ppub https://www.nature.com/articles/s41467-018-05003-z.pdf?origi... Or watch any of Eric Rignot's presentations in youtube. The term is Marine Ice Sheet Instability. This video in my opinion gives a fun demonstration of it https://www.youtube.com/watch?v=jLdaAKIkpKA https://www.youtube.com/watch?v=jLdaAKIkpKA Miscommunicating sea level rise risk is a big problem.

jjcon 5y ago
False, the long term NOAA models are far more complex than simple extrapolation (though that is of course a part of any forecast) and they certainly aren’t linear. Feel free to read up on them yourself: https://oceanservice.noaa.gov/hazards/sealevelrise/sealevelrise-tech-report-sections.html https://oceanservice.noaa.gov/hazards/sealevelrise/sealevelr...
- Gravityloss 5y ago
  Thanks, I was wrong. The report is good reading.
  - wrycoder 5y ago
    But you must have seen something I didn’t. See my comment nearby.
- wrycoder 5y ago
  > Global mean sea level, or the average height of the ocean surface, has risen 6 - 8 inches (15 - 20 centimeters) since 1920. In the continental U.S., relative sea level has risen about 10 - 12 inches (25 - 30 centimeters) over the same period. Observational data from tide gauges and satellites also show that sea level rise, both globally and along the continental U.S., is accelerating, with more than a third of that rise having occurred in the past two and a half decades (see NOAA and NASA portals for altimeter-based global rates and NOAA for local tide gauge rates). So, 30% of the normal one foot per century (somewhat less worldwide) happened in the last 25% of the time. That’s not a big acceleration, that’s measurement error. And yet this report says the rate of rise will nearly triple over the next thirty years. This is simply not plausible. Generally, the report reduced the predictions. Also, they eliminated the 2.5 meter (!) scenario.