As Antarctic Sea Ice Levels Hit Record Lows, Climatologists Warn of Rapidly Rising Oceans
Since 1880, the Earth's average temperature has risen about .85 degrees Celsius. That may not seem like a lot, but it's expected to increase to 2.7 or even 3.6 degrees in the future, and it only takes an incremental change in global temperature to start having catastrophic effects. The most critical area, scientists say, is going to be polar ice around Antarctica—the fate of the world could hinge on preserving those ice shelves.
According to research conducted by Tim Naish of Victoria University of Wellington's Antarctic Research Centre, sea levels have risen an average of 20 cm globally between the 20th and 21st centuries, which has caused researchers like him to sound the alarm on global climate change. Though he acknowledges that sea levels don't rise equally across the planet, the changes can still be dramatic.
Two of the main culprits for the recent rise in ocean levels appear to be higher temperatures (which cause the oceans to expand) and the melting of mountain glaciers. The biggest impact, however, is going to come from polar ice.
Previous estimates in 2013 estimated that melting Antarctic ice would cause ocean levels to rise about one meter by the year 2100, but Naish now thinks that estimate is off: "Science wasn't mature enough at the time of the IPCC report to really deal with what the Antarctic ice sheet contribution would be, so they largely left it out as a dynamic contribution," he says. "If Antarctica does something a bit surprising it could be tens of centimeters more by 2100."
It's heartening to know that 2100 won't have to face the ensuing doomsday scenario caused by massive flooding and rising sea levels, but we're not out of the woods yet...not for several hundred years, at least. According to Naish: "There's the potential of 20 meters of global sea level rise [over the millennium ahead] in the bits of the ice sheets that are sitting below sea level and are vulnerable to a warming world and a warming ocean."
It won't be a gradual change if the Antarctic loses its ice shelves—there can be a sudden, dramatic change over the course of a month. Naish compares it to the buttresses of a cathedral, which hold up the massive, heavy pieces of architecture that can't stand on their own: "Take away the buttresses and the walls fall down; take away the ice shelves around Antarctica and the ice sheets fall into the ocean and cause rapid sea level rise."