Daily Global Sea Ice Area and Trend

In early 2017, the Arctic, Antarctic and Global Sea Ice Area Extent were each at the lowest level in the data set that starts 1979. They each recovered significantly by September 2017. The Arctic Trendline is downward sloping fairly sharply. The Antarctic trend is slightly up.

Context: the average global April sea ice area is about 18.4 million sq. km. In the Spring of 2016, when the satellite responsible for sea ice measurements degraded and interrupted the data series, the Global ice area was nearly exactly (18.4/18.4) equal to the 1979-2008 average for the date. This is well within normal variation. Not subject to urban heat island effects, the trend in global sea ice extent is a primary indicator of climate change, or the lack thereof.

(Source: Cryospheric research at NASA's Goddard Space Flight Center).

Arctic Sea Ice Area and Trend

Arctic Sea Ice Area and Trend

Analysis: Global sea ice is our primary indicator of warming or cooling, but data only go back to 1979, when satellite sensors and analytical programs could get a handle on measuring the area covered by sea ice. Even today it has problems, such as dealing with water on ice, as happens after a warm spell. The sensor sees water, not ice, but this does not mean the underlying ice is gone. If the Arctic loses ice, but the global balance is about the same, there is a lower liklihood of global warming. Per the NOAA National Snow and Ice Data Center, "While Arctic sea ice has set record lows, Antarctic sea ice has set record highs." Something has gone awry when all we hear from the news media and the pro-warming community is that Antarctic is doing as poorly as the Arctic. This dichotomy is not explained by the CO2-based models. Both should be the same. Attempts to explain through evaluations of atmospheric flows or ocean currents do not appear credible.


In 1988, upon making the switch from natural cycle and pollution-based global cooling to CO2-based global warming, this author told his team working on Ocean and Coastal Zones during their first meeting in Moscow, that evidence of warming would be convincing when it included an acceleration in the steady rise of sea level (from the prior ice-age) and a drop in the amount of global sea-ice. Neither has happened. The loss of the satellite sensor that has been acquiring the information has unfortunately disrupted the data record. Alternative means of depicting the polar data sets is now quite good, but an integrated assessment to analyze the global sea ice data is still missing. Nevertheless, here are the two poles that can be visually integrated to show that global sea ice is being strongly decreased by the Arctic and slightly increased by the Antarctic. The Antarctic id=s musch greater, so the loss overall is relatively small.


This page updated or reviewed in February 2018