undefined | Better HN

0 pointsthu21115y ago0 comments

A few meters? That's the scenario where there's some runaway global warming and all the poles melt, right? Actual observed sea level rises are measured in millimeters per year. Historical trends can't lead to Miami needing to move several meters up unless you're talking about, like, 1000 years from now.

There are some problems with the assumption of a flooding crisis. The historical record from tide gauges have been retroactively altered over time, to make apparent level rises in modern times worse and level rises in older times less so (this seems to be a common theme with data from climatologists - they rewrite historical datasets to make the magnitude of changes seem larger).

Additionally at some point they switched to satellites and stopped using tide gauges but it's not clear that's more accurate and may actually be less accurate (but it did make the rises seem larger, so there's a conflict of interest there). In particular, NOAA and NASA disagree by a large amount on what the actual level of rise is. NOAA say it's about half what NASA say it is.

0 comments

eloff5y ago

You can't look at historical trends because it's not rising linearly. Most of the warming and melting will happen in the last decades of this century. That's part of what makes it easy to underestimate.

But you are right that it will keep rising for a thousand years or more. But now at that timeframe we're talking 6-12 meters or more.

This is all in the fairly conservative public estimates that so far have underrepresented the pace and scale of change.

thu2111OP5y ago

Will happen, according to academic models that have been frequently wrong in the past. Projecting prior trends forwards doesn't get you anywhere near meters of rise, that's my point. And no they have not so far under-represented the pace and scale of change, far from it. That's the kind of revisionist history that makes arguments about climatology fruitless. How can we even debate the accuracy of such forecasts when the past is inverted like that? Here's the sort of thing that was actually predicted, from an AP news report in 1989:

https://apnews.com/article/bd45c372caf118ec99964ea547880cd0

UNITED NATIONS (AP) _ A senior U.N. environmental official says entire nations could be wiped off the face of the Earth by rising sea levels if the global warming trend is not reversed by the year 2000.

Coastal flooding and crop failures would create an exodus of ″eco- refugees,′ ′ threatening political chaos, said Noel Brown, director of the New York office of the U.N. Environment Program, or UNEP.

He said governments have a 10-year window of opportunity to solve the greenhouse effect before it goes beyond human control.

As the warming melts polar icecaps, ocean levels will rise by up to three feet, enough to cover the Maldives and other flat island nations, Brown told The Associated Press in an interview on Wednesday.

The most conservative scientific estimate that the Earth’s temperature will rise 1 to 7 degrees in the next 30 years, said Brown.

It's thirty years later now and the temperature rise since then has been at the very lowest end of the most conservative estimate (which was itself so wide that it was basically useless and hardly an estimate at all).

j / k navigate · click thread line to collapse