Exhaustive efforts to calculate temperatures around the world based on satellite and weather station data may have missed a spot: the Arctic.

The area around the North Pole is warming faster than anywhere else in the world, but there’s been a shortage of temperature data from the region. New research suggests that efforts to fill in those data gaps over the last 16 years using calculations and assumptions have underestimated the rate at which temperatures are rising.

That could help to explain why the apparent increases in global temperatures have been slightly lower than forecast by climate models — and slightly lower than had been the case before 1997.