Hansen on understating sea level rise due to climate change

Hansen, the grandfather of all climate research has an essay today in the open access journal Environmental Research Letters arguing that scientists are not communicating the seriousness of sea level rise. And, it is open access, so, no kidney sale required!

Scientific reticence and sea level rise

I suggest that a `scientific reticence’ is inhibiting the communication of a threat of a potentially large sea level rise. Delay is dangerous because of system inertias that could create a situation with future sea level changes out of our control. I argue for calling together a panel of scientific leaders to hear evidence and issue a prompt plain-written report on current understanding of the sea level change issue.

In this paper, Hansen reviews a number of recent studies that point to positive feedback in ice melting (remember, poitive feedback, good for morale, not good for climate change). Hansen then points out that due to these feedback mechanisms, sea level rise is non-linear. His thesis is that all this information is known to most climate scientists, and to a lot of people who maintain even a cursory interest in the matter.

He finishes with a call to action.

There is, in my opinion, a huge gap between what is understood about human-made global warming and its consequences, and what is known by the people who most need to know, the public and policy makers. The IPCC is doing a commendable job, but we need something more. Given the reticence that the IPCC necessarily exhibits, there need to be supplementary mechanisms. The onus, it seems to me, falls on us scientists as a community.

Important decisions are being made now and in the near future. An example is the large number of new efforts to make liquid fuels from coal, and a resurgence of plans for energy-intensive `cooking’ of tar-shale mountains to squeeze out liquid hydrocarbon fuels. These are just the sort of actions needed to preserve a BAU greenhouse gas path indefinitely. We know enough about the carbon cycle to say that at least of the order of a quarter of the CO2 emitted in burning fossil fuels under a BAU scenario will stay in the air for an eternity, the latter defined practically as more than 500 years. Readily available conventional oil and gas are enough to take atmospheric CO2 to a level of the order of 450 ppm.

In this circumstance it seems vital that we provide the best information we can about the threat to the great ice sheets posed by human-made climate change. This information, and appropriate caveats, should be provided publicly, and in plain language. The best suggestion I can think of is for the National Academy of Sciences to carry out a study, in the tradition of the Charney and Cicerone reports on global warming. I would be glad to hear alternative suggestions.

Do we need another study? As we wait for the National Academy of Sciences to conduct a study on how best to communicate the danger of sea level rise, many more villages in India and Bangladesh will go under the sea. Apparently, the sea cannot wait for the best communication strategies. It communicates the only way it can, directly!!

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