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The warmer it gets 
, the faster the sea level rise 
.
We can quantify that increase as a "Transient Sea Level Sensitivity". It has units of m/century/°C.
Our new paper: https://doi.org/10.5194/os-17-181-2021
, the faster the sea level rise . We can quantify that increase as a "Transient Sea Level Sensitivity". It has units of m/century/°C.
Our new paper: https://doi.org/10.5194/os-17-181-2021
We have observed how Earth has warmed since the industrialisation, and how sea level rise has accelerated.
Historical observations gives us a Transient Sea Level Sensitivity of 0.4 m/century/°C.
Historical observations gives us a Transient Sea Level Sensitivity of 0.4 m/century/°C.
Sea level models give us projections for different concentration pathways with different amounts of warming.
These models show a near-linear relationship between warming and the rate of sea level rise. IPCC AR5 has a model sensitivity of 0.27 m/century/°C
These models show a near-linear relationship between warming and the rate of sea level rise. IPCC AR5 has a model sensitivity of 0.27 m/century/°C
The more recent IPCC SROCC also show a near linear relationship response to warming.
On average the sensitivity is 0.39 m/century/°C. However, there is indication of super-linearity. The sensitivity appears to be close to AR5 for the least warm scenarios.
On average the sensitivity is 0.39 m/century/°C. However, there is indication of super-linearity. The sensitivity appears to be close to AR5 for the least warm scenarios.
Expert elicitation results for two warming scenarios implies that future sea level has an even greater sensitivity to warming than seen in the historical record. This also suggests a super-linear response.
Physically we have reasons to expect a super linear response (as seen in both SROCC and in the expert elicitation). It is impossible to join the historical data with AR5/SROCC model results with a super-linear curve. There is already a substantial discrepancy at modest warming.
Summary: we observe a substantial discrepancy between model sensitivity and historical sensitivity. We argue that this indicate a model bias. (read full paper for full argument)
We therefore question whether the models in AR5 & SROCC would be able to reproduce the past sea level record. (Check also the nice hindcast study @AimeeSlangen where they identify some model biases. https://journals.ametsoc.org/view/journals/clim/30/21/jcli-d-17-0110.1.xml )
How much? We dont make a projection, but we can gauge the magnitude of the discrepancy:
- About +25 cm/century (vertical distance between blue and black).
- This corresponds to a difference of ~0.5°C, or 200-300 GtC. (Horizontally)
- About +25 cm/century (vertical distance between blue and black).
- This corresponds to a difference of ~0.5°C, or 200-300 GtC. (Horizontally)
The doi link to the paper may not be active yet. Here's a direct link to Ocean Science: https://os.copernicus.org/articles/17/181/2021/
