Cataclysmic event? An incoming asteroid or the Yellowstone super volcano erupting - both cataclysmic I suppose with a finite chance of occurring. Both of these would probably have a chilling effect over the short term (couple of hundred thousand years).
Runaway warming following some massive release (from somewhere) of a greenhouse gas - possible one supposes but it does not look as if anything like that has happened during the last few million years.
The most likely medium term scenario based upon the rather limited historical climate data we have is that we will slowly move into another ice age. Now that will be cataclysmic for folks living in the Northern temperate zones where most of the current world economic activity takes place.
Cataclysmic is pretty unlikely. Do you think there is 1%+ chance of some major coastal cities becoming uninhabitable or requiring significant engineering to hold back the rising sea?
Interesting question and I suspect difficult to get a sensible answer to. I am assuming that you expect the 20th Century warming period to continue to raise Northern hemisphere temperatures to the levels experienced around 1,000 years ago. Certainly we know that Greenland had a lot less ice then - although we do not know where that water was. I am not sure if we have any information from Northern Canada or Asia. Regretfully I have not heard about any useful data from the South. Was the sea level higher a thousand years ago? Even extrapolating from coastal site evidence might not help as many land masses were still (and are still) rising gently following the last ice age.
There is not a lot of evidence that sea levels are rising substantially at the moment - you had best ask an oceanographer - I would stick with the science rather than ask a "climatologist".
Comments
Cataclysmic event? An incoming asteroid or the Yellowstone super volcano erupting - both cataclysmic I suppose with a finite chance of occurring. Both of these would probably have a chilling effect over the short term (couple of hundred thousand years).
Runaway warming following some massive release (from somewhere) of a greenhouse gas - possible one supposes but it does not look as if anything like that has happened during the last few million years.
The most likely medium term scenario based upon the rather limited historical climate data we have is that we will slowly move into another ice age. Now that will be cataclysmic for folks living in the Northern temperate zones where most of the current world economic activity takes place.
Cataclysmic is pretty unlikely. Do you think there is 1%+ chance of some major coastal cities becoming uninhabitable or requiring significant engineering to hold back the rising sea?
Interesting question and I suspect difficult to get a sensible answer to. I am assuming that you expect the 20th Century warming period to continue to raise Northern hemisphere temperatures to the levels experienced around 1,000 years ago. Certainly we know that Greenland had a lot less ice then - although we do not know where that water was. I am not sure if we have any information from Northern Canada or Asia. Regretfully I have not heard about any useful data from the South. Was the sea level higher a thousand years ago? Even extrapolating from coastal site evidence might not help as many land masses were still (and are still) rising gently following the last ice age.
There is not a lot of evidence that sea levels are rising substantially at the moment - you had best ask an oceanographer - I would stick with the science rather than ask a "climatologist".