Enlarge / A cloud-covered Barents Sea, showing sea ice encroaching from the Arctic Ocean to the north. (credit: NASA Aqua-MODIS)

Many of the threats we know are associated with climate change are slow moving. Gradually rising seas, a steady uptick in extreme weather events, and more all mean that change will come gradually to much of the globe. But we also recognize that there can be tipping points, where certain aspects of our climate system shift suddenly to new behaviors.

The challenge with tipping points is that they’re often easiest to identify in retrospect. We have some indications that our climate has experienced them in the past, but reconstructing how quickly a system tipped over or the forces that drove the change can be difficult. Now, a team of Norwegian scientists is suggesting it’s watched the climate reach a tipping point: the loss of Arctic sea ice has flipped the Barents Sea from acting as a buffer between the Atlantic and Arctic oceans to something closer to an arm of the Atlantic.

Decades of data

The Norwegian work doesn’t rely on any new breakthrough in technology. Instead, it’s built on the longterm collection of data. The Barents Sea has been monitored for things like temperature, ice cover, and salinity, in some cases extending back over 50 years. This provides a good baseline to pick up longterm changes. And, in the case of the Barents Sea in particular, have we been watching as any major change took place?