There’s a good chance you’ve seen it in the news this week; all over the world our ice is melting due to global warming. In the last two decades, the melting rate of the ice in Greenland is 33% higher than 20th century averages. Within the past fifty years, this ice sheet has shed enough to add about half an inch of water to the world’s oceans. Half an inch may not sound like much but when the world’s water level raises even a couple of millimeters the effects are noticeable. Right now, scientists are studying these rates and trying to figure out what that means for us in the future.
Originally, they assumed that the ice was melting from the top when warm pockets of air rested over the sheet. But when glacier Jakobshavn retreated, the air wasn’t warm. A team of oceanographers led by David and Denise Holland thought that the ice could have melted from below instead of above. They pieced together bits of data from the Danish fisheries service that had studied the Jakobshavn for years to see what kind of conditions were good for fish. They found that the reason was not just the sun beating down on the surface of the ice but also a long, steady stream of warm ocean water that had reached the glacier.
But where had all the warm water come from? Well when ocean water goes through slight changes(in temperature or currents) they have the potential to affect ice anywhere they make contact. It’s a relief that these scientists could find out what was behind the melting but now we’re faced with another problem: that the ocean has been absorbing over 90% of all the extra warmth since the Industrial Revolution began. To put that into perspective, that started in 1760. That’s over two centuries ago and humans have created a lot of excess heat since then.
So what does this mean for us? As glaciers and ice sheets around the world melt, the water gets warmer which starts a chain effect that could eventually result in higher water levels and a warmer climate than before. Thankfully the ice sheet hasn’t collapsed yet but it could happen soon if we keep on the path we’re going on now. If we can slow this process down, now is the time to do it. Maybe the ice sheets won’t melt as much before we do.