1.5 m sea level rise this century, that is. Nature sez the “estimate released today says that it could be as as much as 1.5 metres (4.9 feet) by the end of this century”. Their source seems to be Reuters, and we’ll pause briefly to condemn the oh-so-typical inflation of the worst case from the range into the only number mentioned in the headline. Sigh.
So… Melting glaciers, disappearing ice sheets and warming water could lift sea levels by as much as 1.5 metres (4.9 feet) by the end of this century,… Presented at a European Geosciences Union conference, the research forecasts a rise in sea levels three times higher than that predicted by the Intergovernmental Panel on Climate Change (IPCC) last year… Svetlana Jevrejeva of the Proudman Oceanographic Laboratory in Britain said the estimate was based on a new model allowing accurate reconstruction of sea levels over the past 2,000 years… But the pace at which sea levels are rising is accelerating, and they will be 0.8-1.5 metres higher by next century… say Reuters. But who told them so?
I presume the relevant press conference must be Will Planet Earth become Planet Ocean? (gurk). Which says Global sea level is expected to rise in this century between 18 and 79 cm according to the IPCC 4th Assessment (allowing for uncertainty in the dynamic instability of ice sheets). It seems that this dramatic trend is set to continue beyond the 21st century, making the field of research concerned with measuring sea level change more important than ever.
So its rather unclear where 0.8-1.5m comes from or how you can get that from monitoring past changes. Extrapolating past change into the future won’t get you more than 0.3m for the 21st century. There is a vaguely promising link on JevreSvet‘s homepage, but… its broken. Sack that webmaster.
Oh, and when I say I don’t believe in 1.5m this century… I don’t rule it out as impossible; but I can’t see how you can get it from this stuff.
[Update: it made it onto R4 at 10; and the beeb has it too. Apparently “The rapid rise in the coming years is associated with the rapid melting of ice sheets.” I think its entirely likely that *if* SLR is much larger than IPCC projections then the excess will come from ice sheets. But how you get that from past data is murky.]