NASA oceanographers announced this month that sea level rose, on average, 3 millimeters (0.1 inches) per year between 1993 and 2005. They think about half came from melting ice and half from thermal expansion as the ocean soaks up heat from global warming. The trend line seems pretty obvious.
Equally obvious are the perilous implications for coastal, sea-level cities like Venice. Venice's countermeasures, including the MOSE dike system and the raising of the lagoon-facing quays, can forestall flooding. But if the trend is relentless, we're really just buying a few ticks on the geologic time game clock. And unless we begin to actively think about what can be done to reverse the trend itself, we will have to consider accepting Venice's eventual surrender to the sea.
Ah, but the linear trend is not that spooky, right? Let's see, an inch every 10 years or so ... less than a foot a century, right? Maybe we'll just roll up our pant legs a bit and build higher walls.
Unfortunately, there's reason to believe the trend may become curvilinear, ascending in a graceful, lethal upward swoop. Earth's floating glaciers function as a kind of mirror, reflecting some of the sun's energy out of the atmosphere and into space. But as the floating glaciers melt from the effects of global warming, this mirror effect disappears and the sun's energy can directly heat the ocean previously beneath the glaciers . And the ocean retains, rather than reflects heat.
So while we may be seeing a gradual sea rise due to glacial melt, once the glacial is gone, things may get hot fast. Very fast. And the bathtub quickly overflows.
Please see the film An Inconvenient Truth. It's in theaters across the country right now. It lays bare the incredible peril in which human-derived global warming has placed our planet. It doesn't matter what your political persuasion is, or for that matter, what side of the global warming issue you find yourself. See the film, judge for yourself. I guarantee you'll be moved, if not radicalized.
The film follows former Vice President, Al Gore, as he trudges from city to city across the globe making a stunning multimedia presentation of what he calls our "planetary emergency". Gore has redirected his stumping skills, and instead of campaigning for himself, he's asking us to vote for the Earth in a bid to raise consciousness and stir political action. The film is frightening, hopeful, extremely intelligent and very, very motivating.
Politics and politicians polarize. I have no idea of your political POV, but there's about a 50% chance, in this country, it's different than mine. Al Gore has advanced a liberal Democratic agenda his whole life. Forget that. For real. He is not selling anything in this film other than defense of the planet.
I was fortunate enough to see Gore's presentation live last February at the TED Conference. Afterward, I spoke to him about Venice, a city he also loves. I told him a bit about the controversy around the MOSE floating dike project, and he talked about the lumbering political processes that are needed to galvanize people around real solutions.
I'm hoping this film quickens the step.