Development Roast Giving international development a proper roasting
By: Lykke E. Andersen*
The 21st of September marks the beginning of spring in the southern hemisphere. In Bolivia, it is also the day of Love, Peace, Students, Doctors and Photographers (!!). Most relevant for this article, however, today is usually the day of the year that the extent of sea ice in the northern hemisphere reaches rock bottom, much to the concern of polar bears (or at least people concerned about polar bears). In the southern hemisphere, on the other hand, sea ice usually reaches its maximum extent on this day (possibly to the delight of penguins).
In this satellite era, the extent of sea ice is an easy-to-measure indicator about the state of the global climate (warmer climate -> less ice), but the extent of sea-ice itself also affects the global climate (less ice cover -> lower albedo (reflectance) -> warmer climate). Thus, many people watch this indicator closely, and the availability of several independent web-sites with daily updated data on sea-ice extent makes this possible, and even delightful (at least for data-freaks like me).
On the 20th of September 2012, the sea ice extent in the northern hemisphere reached an all-time low (since the beginning of satellite measurement in 1979). The exact value depends on the method of measurement, but Cryosphere Today (which is my favorite sea ice web-site, due to the cool, daily updated, interactive graphics) put the minimum at 2.24 million square kilometers of ice. This year’s minimum seems to be about 50% larger at 3.5 million km2, which means that we are probably not going to see any particularly alarming headlines with new drowning polar bear images this year.
Meanwhile, in the southern hemisphere, sea ice extent has today reached an all-time high (since 1979 when satellite records began, of course) of 16.8 million km2. Actually, most of the days this year, we have set records for southern hemisphere ice extent, but today stands out visually with a value more than 0.7 million km2 higher than previous years’ records (see Figure 1).
Figure 1: Southern Hemisphere Sea Ice Area (as reported by Cryosphere Today)
What does this mean for the global climate? I don’t know. But right now the penguins (southern hemisphere) seem to have more advantages than the polar bears (northern hemisphere).
Several more records are likely to be broken this year, so I suggest that you keep watching Cryosphere Today.
* Dr. Lykke E. Andersen is the Director of the Center for Economic and Environmental Modeling and Analysis (CEEMA) at the Institute of Advanced Development Studies (INESAD), La Paz, Bolivia.
