NASA scientists crunched data from satellite missions to determine that ice melt in Antarctica and Greenland over the last 16 years raised sea levels about half an inch. Put another way, the researchers said both locations contributed 5,000 gigatons of water to the oceans which is enough to fill Lake Michigan.
Ice melt and ocean expansion due to global warming are the primary contributors to sea level rise. Experts are concerned that the rate of melting is picking up pace. Helen Fricker, a glaciologist at the University of California-San Diego, told National Public Radio, “How much ice we are going to lose, and how quickly we are going to lose it, is a really key thing that needs to be understood, so that we can plan.”
There are two main forces driving the melting in Antarctica and Greenland. In Antarctica, warming oceans are melting floating ice shelves, which is allowing land based ice to flow into the ocean. In Greenland, warmer atmospheric temperatures are melting ice and creating run-off. At the same time, the warmer air is also causing glacial ice to calve off and fall into the ocean.
If all the ice melted in Greenland alone, scientists estimate global sea levels would rise 23 feet. Fricker told NPR, “There’s a lot of infrastructure and airports and people that live right on the ocean, and these people are going to feel the effects of sea level rise that’s resulted because the ice sheets have melted.”