You may have seen headlines over the last few days from scientific media outlets espousing the conclusions of a recent study on ice loss in Antarctica. The accompanying articles explained that the rapid decline in Antarctic ice over the last decade has resulted in measurable gravitational fluctuations in the areas with the most loss.
I have to say that it is quite surprising to me that some of the more credulous pop-culture media outlets haven’t yet spun this story into another sensationalized doomsday prediction. I have to wonder if that’s because the paper in which these conclusions appeared is difficult to understand. Even the publicly available abstract doesn’t make a whole lot of sense to anyone not versed in the nomenclature of physics and other environmental sciences. Nevertheless, this paper should sit as a cherry on top of the mountain of evidence available to confirm and loudly warn about climate change. As though any reasonable person needs more proof.
In light of this I thought I’d take a moment to explain what these findings mean; and I’m sorry to rain on anyone’s parade, but it doesn’t mean you’re going to be any lighter if you travel to Antarctica.
The paper in question, which was published in the American Geophysical Union’s Geophysical Research Letters journal in August of 2014, provides analysis of data collected by the European Space Agency’s (ESA) superstar Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite. GOCE is the first in a series of Earth Explorer satellites the ESA is working on, as a part of their Living Planet programme. This satellite is designed to offer targeted geophysical measurements of specific gravity values along its low-altitude orbital path. It is the most sensitive gravitational sensor ever used to map the Earth’s gravity field, offering the highest resolution capabilities ever.
The team of researchers, led by Dr, Johannes Bouman of Deutsches Geodätisches Forschungsinstitut (German Geodetic Research Institute), used the GOCE data combined with data from NASA’s Gravity Recovery and Climate Experiment (GRACE), which is much less sensitive, and determined that loss of ice in the areas of several ice-basins in the Amundsen Sea sector of West Antarctica has resulted in slight gravitational changes.
As mentioned, the paper employs a great deal of scientific jargon, which makes it difficult for the layman to understand what their findings mean in the real world. Bouman et al assert that ice loses have been in the range of -67 to -63 to -55 Gt/yr between November 2009 and June 2012.
To put that into perspective, a gigatonne, which is a unit of weight and is expressed as Gt, is equal to one trillion kilograms. That means that the loss in that region is on the order of 67 trillion kilograms of ice in a matter of three years. Environmental experts claim that the above measurements are equivalent to a loss of 500 cubic kilometers of ice every years.
It doesn’t take a genius to see how losing that much ice is going to impact our climate. Adding that much water to our oceans is responsible for massive sea-level rise, ocean de-salinization, and, as it turns out, fluctuations in our gravitational field.
Our gravitational field is the attractive force generated by the mass of the Earth on all objects on its surface or in its orbit. We feel it as weight, and you measure it every time you step on your bathroom scale. But that gravitational field isn’t uniform or homogenous; it’s stronger in some areas and weaker in others. In places with large mountain ranges, like the Canadian Rockies, or the Russian Urals, the field is stronger due to the density of the rock, which ultimately means that the land has more mass in those regions. And greater mass equals a stronger gravitational field. The same is true for the Polar Regions where the ice is nearly as dense as rock. But ice, unlike rock, can rapidly disappear with the rise of global temperatures, which when lost, obviously means that there is less mass in that region than there once was, leading to gravitational fluctuations.
Now, the fluctuations Bouman and his team found are miniscule, and in fact, without the GOCE satellite, a measurement of such small fluctuations would never have been possible. Ultimately, what this paper and its conclusions mean, is – yet again – that climate change has real, measurable effects on our environment, and can no longer be denied.
Our planet is changing, as it has a record of doing over the eons. These changes are likely to be detrimental to our comfort and even our survival. Whether you believe these climate changes are due to human activity, which seems to be obvious at this point, or if you believe rising global temperatures are caused by something else, we’ve reached a point where it hardly matters…we need to take action in an effort to minimize whatever effect we do have on the environment, and hopefully give our children a better chance of inheriting a planet capable of sustaining them.
 Bouman, J., M. Fuchs, E. Ivins, W. van der Wal, E. Schrama, P. Visser, and M. Horwath (2014), Antarctic outlet glacier mass change resolved at basin scale from satellite gravity gradiometry, Geophys. Res. Lett., 41, 5919–5926, doi:10.1002/2014GL060637.