West Antarctic Ice Sheet Growing As Southern Ocean Warms Slightly
The West Antarctic Ice Sheet is growing, but I bet you didn’t read about it in the news.
Nor would you probably be able to find it if you entered “West Antarctic Ice Sheet Growing” in a Google search. That search would likely uncover one 2015 publication by NASA’s Jay Zwally in the Journal of Glaciology using actual weather data that showed increasing snowfall, primarily over East Antarctica, was adding a small amount of ice. That report generated a flurry of coverage, but of course in the current era of public shaming of any deviation from the apocalyptic orthodoxy, you don’t hear much about it anymore.
Which may explain why you have heard nothing about this new publication which has been accepted in Journal of Geophysical Research-Atmospheres but isn’t in print yet: “A New 200‐Year Spatial Reconstruction of West Antarctic Surface Mass Balance,” by Yetang Yang (Shandang Normal University, China) and five co-authors. Here’s the money quote:
When averaged over the whole WAIS [West Antarctic Ice Sheet] , SMB [surface mass balance] shows a significantly negative trend (-1.9± 2.2Gt yr-1decade-1, p<0.01) [loss of ice] during the 19th century, but a significantly positive trend (5.4± 2.9Gt decade-1, p<0.01) [gain in ice] in the 20th century. This is not consistent with the previously reported insignificant changes in snow accumulation over the WAIS during the past 50 years…One possible explanation is the lack of recent ice core records in the [previously published work over the] AP [Antarctic Peninsula] and coastal zones in these studies and a high weight given to cores from the interior of Antarctica.
Translation and color commentary:
Although measurements are rather hard to come by, it is clear that the Southern Ocean surrounding Antarctica has warmed a few tenths of a degree (C) since 1900. This is known from sporadic explorer records, such as Scott and Shackleton, and then with much more confidence after the instrumentation program from the international geophysical year in 1957-8.
Even a slight ocean warming results in a substantial increase in the moisture flux over the cold Antarctic continent, where, with the exception of over the Antarctic Peninsula (the portion of the continent that juts out towards South America), all precipitation falls as snow. Increasing the moisture would therefore increase the snow load which should increase the ice mass balance, which is why I find this result (and Jay Zwally’s) not particularly surprising.
- The WAIS experienced a significant loss of ice in the 19th century when it was colder than the 20th century average.
- The WAIS experienced a significant gain in ice in the 20th century and early 21st century when it was warmer than the 19th century average.
- The gain in ice in the last 110 years was 2.8 times the loss in the 19th century.
- Apparently this isn’t newsworthy or even Google-worthy.
You can have a look at the abstract.