December 11, 1972 is the date that changed the world of sea ice data. It was then that the Electrically Scanning Microwave Radiometer(ESMR) was launched into the sky, placing it aboard NASA’s Nimbus-5 satellite. This allows us to track daily changes in the extent of sea ice cover over the polar regions using passive microwave data. These activities today give us the opportunity to better observe how the Arctic and Antarctic sea ice is declining under the influence of global warming.
Research on global warming and its impact on sea ice
When the first ESMR measurements were launched, there was disagreement in the scientific community about whether the changes taking place in the climate were the result of human activity. Scientists understood how the greenhouse effect was created, but research on the phenomenon didn’t really begin until the 1950s and 1960s, and global warming wasn’t widely recognized as a problem until 1988. During his testimony before the U.S. Congress, James Hansen, a NASA climatologist, said he is 99% certain that the rise in global temperatures is not a natural change occurring in the climate, but the result of human activity.
Impact of climate warming on sea ice – the importance of measurements
Comparing measurements over the first decades showed little change. Only the withdrawal in 1977. The ESMR, and the introduction of new and improved instruments, has made it possible to observe sea ice in detail. Over the years, the results of the research have been getting worse, but they have also become more and more important. They helped provide strong observational evidence that the enhanced greenhouse effect accelerates the melting of sea ice.
For example, coverage in January 1982 was about 15.177 million km², and in January 2022 has decreased to 13.877 million sq. km.
The figure above illustrates only one comparison in years, showing the dynamics of change – the shrinking of the ice cap, which is decreasing year by year. And although the initial measurement data showed a very slow loss of sea ice volume, today we know that the phenomenon was worth watching. This way we know its scale and can take measures to prevent it.