Experts in gas study now 750 miles from North Pole

The team from the Catlin Arctic Survey are camping on the ice and collecting samples from the sea below to see how rising levels of the greenhouse gas, which dissolves into sea water and makes it more acidic are affecting the Arctic Ocean and its marine life.

The research includes drilling a hole through ice around five feet thick to take measurements of the ocean and gather samples of plankton as far down as 200 metres (220 yards), as well as collecting ice core samples for further analysis.

The unique project, which also involves a separate team of explorers trekking across the ice to collect other samples, is giving the scientists a rare chance to gather data during the Arctic winter.

It will enable them to analyse the impacts of acidification – which can harm the ability of marine creatures to form their shells – in cold conditions, where it is likely to be greatest as the carbon dioxide dissolves most quickly.