A new “semi-empirical” method of estimating sea level rise shows that earlier techniques underestimated the likely rise, according to research published in Science online.

Coastal City Cuts it CloseOcean expert Stefan Rahmstorf noticed a correlation between the warming in the atmosphere and the rise of sea levels over the 20th century. Having also watched the actual rate of sea level rise pass earlier computer estimates, Rahmstorf integrated his real-world observations with the models.

Rahmstorf estimates a possible sea level rise of anywhere from 50 to 140 centimeters, up from 9 to 88 cm. The new numbers would put North Atlantic shore cities, like New York and London, at higher risk for storm surges, which helped flood New Orleans.

Rahmstorf’s research has higher accuracy than previous models, explaining why he insists that:

We should not take this risk. We should start with very effective emission reduction measures. The global temperature increase should be kept to under 2°C.

Already, we have experienced a .8°C increase, meaning we are almost halfway to where scientists have warned us not to go, and we need to stop pushing the envelope.

Read more at Climate Progress.