Past performance may not always predict future results in the stock market, but in the Earth sciences, it can tell us a hell of a lot. Since we only have the one planet, examples of some processes can only be found in the past. That’s why so much effort goes into studying the past behavior of the Greenland and Antarctic ice sheets. We need context for what we’re currently seeing and some ideas about what’s likely to happen next.
While many studies look tens of thousands or even millions of years into the past, much more recent histories can also be of interest. We’ve only had satellites measuring changes in the Greenland ice sheet since the early 1990s, so what happened over the preceding century is much less clear. That makes it difficult to answer questions about Greenland’s contribution to the full century's sea level rise or the ice sheet’s natural short-term variability.
But in a new study, a team led by Kristian Kjeldsen and Niels Korsgaard of the University of Copenhagen has managed to fill in this gap through some clever, if tedious, research. They took advantage of a trove of stereo aerial photos taken in the late 1970s and 1980s as part of a survey of Greenland.