Every year, sea ice cover in the Arctic Ocean shrinks to a low point in mid-September. This year it measures just 1.44 million square miles (3.74 million square km), the second-lowest value in the 42 years since satellites began taking measurements. The ice today covers only 50% of the area it covered 40 years ago in late summer. The Arctic is way too hot!
As the Intergovernmental Panel on Climate Change (IPCC) has shown, carbon dioxide levels in the atmosphere are higher than at any time in human history. The last time that atmospheric CO2 concentrations reached today’s level – about 412 parts per million – was 3 million years ago, during the Pliocene Epoch. That means the Arctic hasn’t been this warm in 3 million years.