In the 64 years, that NASA has existed Administrators of the agency were forced to answer the much-discussed what’s the point? question. What’s the purpose, of lawmakers and taxpayers inquiring to spend on space, when there are many issues on Earth? NASA has always offered a quick response by pointing to the many different generations of Earth-observing satellites that they have launched, which have kept a close eye on the climate, weather erosion of land and many other things. The only thing the agency hasn’t said was that it’d be interested in what the satellites reveal to us.
This week as NASA announces, the results from space regarding the state of the Earth have been particularly troubling. In two papers–one published in Nature and the other within Earth System Science Data–scientists looked at 25 years of observations from seven American and European satellites that are monitoring the Antarctic and came up with terrible news to report.
According to the paper the loss of mass from Antarctica’s ice shelves, or ice that extends past the coastline has been more than twice the size previously thought. Since 1997 12 million metric tons of ice have disappeared, the research illustrates, in contrast, comparison to six million thought to be.
“Antarctica is breaking apart around its borders,” Chad Greene, an assistant professor at Caltech’s and NASA’s Jet Propulsion Laboratory and a co-author on the Nature paper released in an announcement.
This is bad news not only for Antarctica however, but also for the entire world. Floating shelves are a source of support for the ice that covers the Antarctic continent, and the more shelving that is destroyed as it is, the more land-based ice can be lost, adding substantially to the increase in sea levels across the globe.
The key to the newly released findings was satellite measurement techniques that employ altimeters that do not determine the vertical expanse of the ice but instead the horizontal elevation. The thickness of the ice as measured by the instruments is decreasing, suggesting it is that the warmer ocean is melting it from below, which makes them more fragile, thinner and more likely to melt away.
Prior to the two studies, altimeters hadn’t been utilized to study this phenomenon across all of the Antarctic continents. One of the difficulties of the study was that satellite images are difficult even for an experienced eye to comprehend.
“For instance,” said Greene, “you might imagine gazing at the satellite image and trying to determine the distinction between a white glacier, white ice shelf sea ice and white clouds. It’s been a daunting task. We now have enough data from several satellite sensors to have an accurate image of how Antarctica’s coastline changed over the past few years.”
The worst part is that the loss of ice shelves in the last 25 years is expected to outstrip the previous few years or so. Even even if global warming did slow, scientists don’t believe the ice shelves could return to the levels they were before 2000 at any time in the next century. “Antarctica’s largest Ice shelves.” The NASA statement warns that “all are likely to be heading to major calving events over the next 10-20 years.”