Climate Change - Arctic sea ice
Arctic sea ice melts back in Summer, and then refreezes in Winter.
The area of Arctic sea ice is largest in March each year, and at its lowest each September.
It is reducing over time - the graph comes from the US National Snow and Ice Data Center.
The NSIDC also publish this graph, which is updated every day.
Research suggests the remarkable decline of Arctic sea ice over the last century is far beyond anything seen for a long time.