Global warming has led to rise in sea levels as increased global temperatures have slowly melted away the polar ice caps. While this is commonly known, the exact amount by which sea levels have risen was not until recently, when a new study, for the first time, quantified the rise, putting the number at 11 millimeters.
According to a joint study supported by the US and European space agencies, NASA and ESA, and a part of the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE), global sea levels have risen by 11mm over the past two decades, with polar melting contributing to about one-fifth of the global rise in sea levels since 1992.
The present research involves the work of more than 20 polar research teams. Details of the study have been published in the journal, Science.
With data from satellite surveys, the flow of glaciers and ice mass’ gravitational effects, the researchers were able to determine the global sea level rise at 11.1mm with a 3.8mm uncertainty either way.
The study showed that the melting of the polar ice caps had increased over the past 20 years with different regions seeing different rates. Lead author Prof. Andrew Shepherd of Leeds University explained, “We can now say for sure that Antarctica is losing ice and we can see how the rate of loss from Greenland is going up over the same period as well. Prior to now there'd been 30 to 40 different estimates of how the ice sheets are changing, and what we realized was that most people just wanted one number to tell them what the real change was. So we've brought everybody together to produce a single estimate and it turns out that estimate is two to three times more reliable than the last one."
The present research, though not making any future predictions, has, according to Prof. Shepherd, brought together “20 years of disagreement” between the different polar research teams and that the present figure is in accordance to climate change predictions. “We would expect Greenland to melt more rapidly because the temperatures have risen. We would expect West Antarctica to flow more quickly because the ocean is warmer. And we would also expect East Antarctica to grow because there's more snowfall as a consequence of climate warming," he said.