17 years of near-zero trend in September sea ice demolishes claim that more CO2 means less sea ice

by Polar Bear Science, Sep  23, 2023


If the hottest year ever can’t precipitate ‘ice-free’ conditions in September, what’s it going to take? Arctic sea ice failed to nose-dive again this year, undoubtedly disappointing expects who have been anticipating a ‘death-spiral’ decline for ages. Arctic sea ice hit its seasonal low sometime around mid-September this year and although the precise value hasn’t been published, the average September ice coverage will likely be about 4.2 mkm2 once it gets announced in early October.

This means we have now had 17 years of a near-zero trend for September sea ice, extending the nearly-flat trend NSIDC sea ice experts acknowledged four years ago. This surely busts a huge hole in the prevailing concept that more atmospheric CO2 causes less summer sea ice. Note that CO2 levels measured in August 2023 were 419.7 parts per million (ppm), compared to 382.2 in August 2007, a rise of 37.5ppm with no corresponding decline in summer sea ice (and vs. 314.2 ppm in 1960). Measured in metric tons, CO2 emissions due to fossil fuels rose from 31.1 billion in 2007 to 37.1 billion in 2021 (last year of data), again with no corresponding decline in summer sea ice.

Background