Stefan Rahmstorf:
> Given the impacts, the risk of an AMOC collapse is something to be avoided at all cost. As I’ve said before: the issue is not whether we’re sure this is going to happen. The issue is that we need to rule this out at 99.9 % probability. Once we have a definite warning signal it will be too late to do anything about it, given the inertia in the system.
> The new study confirms past concerns that climate models systematically overestimate the stability of the AMOC. About the crucial AMOC freshwater transport in models, they point out that most models don’t get it right: “This is not in agreement with observations, which is a well-known bias in CMIP phase 3 (38), phase 5 (21), and phase 6 (37) models.” Most models even have the wrong sign of this important diagnostic, which determines whether the feedback on Atlantic salinity is stabilising or destabilising, and this model bias is a key reason why in my view the IPCC has so far underestimated the risk of an AMOC collapse by relying on these biased climate models.
Eesti teadlased:
> Tema hinnagul on Hollandi teadlaste mudeleksperiment ebarealistlik. Häiritus, mis mudelis ookeanile väga suure magevee hulga lisamisega antakse, on märksa suurem, kui osutavad isegi kõige karmima soojenemisega kliimamudelid. Posti sõnul oligi eksperimendi mõte kinnitada hoopis seda, et AMOC-i seiskumine on põhimõttelisel võimalik.
1 comment
https://www.realclimate.org/index.php/archives/2024/02/new-study-suggests-the-atlantic-overturning-circulation-amoc-is-on-tipping-course/
Stefan Rahmstorf:
> Given the impacts, the risk of an AMOC collapse is something to be avoided at all cost. As I’ve said before: the issue is not whether we’re sure this is going to happen. The issue is that we need to rule this out at 99.9 % probability. Once we have a definite warning signal it will be too late to do anything about it, given the inertia in the system.
> The new study confirms past concerns that climate models systematically overestimate the stability of the AMOC. About the crucial AMOC freshwater transport in models, they point out that most models don’t get it right: “This is not in agreement with observations, which is a well-known bias in CMIP phase 3 (38), phase 5 (21), and phase 6 (37) models.” Most models even have the wrong sign of this important diagnostic, which determines whether the feedback on Atlantic salinity is stabilising or destabilising, and this model bias is a key reason why in my view the IPCC has so far underestimated the risk of an AMOC collapse by relying on these biased climate models.
Eesti teadlased:
> Tema hinnagul on Hollandi teadlaste mudeleksperiment ebarealistlik. Häiritus, mis mudelis ookeanile väga suure magevee hulga lisamisega antakse, on märksa suurem, kui osutavad isegi kõige karmima soojenemisega kliimamudelid. Posti sõnul oligi eksperimendi mõte kinnitada hoopis seda, et AMOC-i seiskumine on põhimõttelisel võimalik.