A new article in Nature Geoscience, Central West Antarctica among the most rapidly warming regions on Earth (subs. req’d), presents up-to-date information on conditions of the West Antarctic Ice Sheet (WAIS). The most common theme of climate science is present within this story: warming is occurring faster than scientists thought it was or projected just a few short years ago. This study compares its results against similar efforts and confirms some of the fears of the cryosphere. Large portions of both the Arctic and Antarctic are among the spots warming the fastest on Earth. What does this mean? It means accelerating sea level rise, influxes of fresh water into the world’s oceans, and rapidly changing ecosystems. It means there are likely other effects of anthropogenic global warming occurring across the globe, but because our observation networks are sparse, we’re just not aware of them yet.
Two important figures from the paper:
Figure 1. Color shadings show the correlation between the annual mean temperatures at Byrd and the annual mean temperatures at every other grid point in Antarctica, computed using ERA-Interim 2-meter temperature time series from 1979 to 2011. The star symbol denotes the location of Byrd Station. The black circles denote the locations of permanent research stations with long-term temperature records.
The warming observed at Byrd Station is, by incorporating ERA-Interim reanalysis data, also exists across a significant portion of West Antarctica. This development’s significance is this: the WAIS rests on bedrock and is grounded below sea level. As the WAIS melts, the meltwater runs to the ocean from the land, raising sea levels. If sea level around Antarctica rises high enough, the bottom of the WAIS will be exposed to water, which will hasten its melt.
Figure 2. Annual mean surface temperature change (trend×number of years) during 1958–2009 from the Byrd record (red and black circle) and from the CRUTEM4 data set (rest of map).
Figure 2 puts the Byrd warming into global context. There are areas in the Arctic and now the Antarctic that have observed +2.4°C warming from 1958 through 2009. The long time period is representative for climate and the non-zero warming represents change. On a localized scale (WAIS), the warming observed at Byrd and likely at nearby locations probably counteracted the cooling resulting from increased circumpolar westerlies. Those westerlies, as I’ve written about in my State of the Poles posts, were themselves the result of cooling in the Antarctic stratosphere as ozone depletion occurred. In essence, the strong winds blowing across lines of longitude near Antarctica largely prevented warm air at higher latitudes from being blown across the continent. The Byrd warming therefore presents an interesting case where this phenomenon isn’t the only one that occurs.
As the Montreal Protocol continues to reduce the amount of ozone-depleting substances in the stratosphere and the ozone layer replenishes itself, the anomalous westerlies will likely subside. As additional warm air is advected over Antarctica, the continent will experience fuller effects of global warming. In turn, the rest of the planet will experience the results of those effects. This is an example of one science policy working while another science policy remains mostly flatlined. The 2012 18th Conference of Parties continued to demonstrate that the same framework that allowed for the Montreal Protocol to be negotiated and successfully implemented has not and will not allow for a climate protocol. Decades have passed while negotiators have tried time and again to do the same thing over and over. A new approach is required. Local, bottom-up efforts need to be expanded and stoked. Someone somewhere has a much more effective set of solutions. Heck, a bunch of someones somewheres have solution sets. They need to be incubated and allowed to develop. We need to take control of those strategies and processes.