Arctic sea ice has reached its annual minimum extent for 2018. This year is tied with 2008 and 2010 for the sixth lowest annual minimum in the satellite era (since 1979), and it continues the downward trend in Arctic ice resulting from our changing climate. All 12 of the lowest extents have come in the last 12 years.
According to the National Snow and Ice Data Center, the minimum extent was 1.77 million square miles (4.59 million sq km), which would cover 57% of the area of the contiguous 48 United States. A dramatically warm September off the coast of eastern Siberia, 13-16°F (7-9°C) above average, helped reduce the sea ice in this area into the latter part of September. This year’s minimum extent occurred twice, on September 19 and 23. September 23 is one of the latest dates on record for the minimum, tying with 1997.