This coming Saturday, April 14th, New Yorkers will demonstrate how the global climate crisis could strike on our own city streets. Dressed in blue, they'll stretch north from Battery Park in two lines along the "projected eastern and western 10-foot waterlines that may one day redefine lower Manhattan," if the sea level rises 10 feet -- just one scenario of how the city's watery edge may be redrawn because of global warming.

Organizers are inviting everyone out to be part of this "Sea of People," which is just one of thousands of equally exciting and creative demonstrations planned for this Saturday all over the country. Communities are turning out to demand national action on global warming as part of the Step It Up campaign to demand that Congress enact policies that, by 2050, will cut by 80 percent our nation's atmospheric carbon pollution, whch is currently a full 25 percent of all greenhouse gas emissions in the world.

Most New Yorkers probably don't think of the ocean as a big factor in their daily lives, Thanks to our concrete canyons insulating us from the weather, our bridges arching high above the estuarine rivers and bays, and our subways traveling hundreds of feet under them, it's easy to forget that New York is a maritime city, and one with an aging and vulnerable infrastructure that by most accounts isn't ready for what the upcoming decades may dish out.

History shows us the damage that storm surges can do to the city, even when they're not intensified by the warming global climate: according to the Columbia University Center for Climate Systems Research, an 1821 hurricane hit Brooklyn and Manhattan with a 13-foot storm surge in just one hour's time. The "Great Hurricane of 1838" caused a wall of water 25 to 35 feet high that killed 700 people. And during 1960's Hurricane Donna, water levels at the Battery reached 8.5 feet above sea level.

The idea of our city being inundated with water is scary, but April 14th will be a day of hope. Come out and join the "sea of people" that will stand up to make sure the real sea stays down.

Image: flickr/Xerones