Nature Climate Change has published a new paper on the warming oceans which compares Ocean Heat Content (OHC) simulations in climate models to some of the newest and best OHC observational data sets from Domingues (2008), Ishii (2009), and Levitus (2009). The paper makes several important points:
- The 0-700 meter layer of the oceans warmed 0.022 degrees C to 0.028 degrees C on average per decade since 1960.
- Climate model simulations which include the most complete set of external forcings – natural (solar and volcanic) and anthropogenic (greenhouse gases and sulphate aerosols) – are consistent with the rate of warming observed over the past 40 years and multimodel response including volcanic forcings projected forward using the IPCC SRES Scenario A1B
- Thus: The ocean warming observed over the past 40 years cannot be explained without anthropogenic greenhouse gas emissions; it is a ‘fingerprint’ of human-caused global warming.