SEATTLE - Hundreds of demonstrators gathered on Saturday and marched, calling for politicians to take immediate action to cool the effects of global warming. The rally was one of more than 1400 held across the country on what's being called the National Day of Climate Action. Those gathered for the "Step It Up, Congress" rally wanted to send a clear message to lawmakers - cut carbon emission by 80 percent by the year 2050.

The demonstrators marched from Occidental Park to Myrtle Edwards Park carrying signs and reciting, "carbon down, bring it down."

One woman present at the rally, Dorothy Cutting, said she traveled from Canada for the event. Cutting said she tries to convey her message to every person she meets.

"I like to say to people 'Cutting', like cutting emissions, so then they don't forget. Well, they may forget me, but they think cutting emissions, yes," she said.

But rally organizers said individuals, rallies and marches matter only so much if governments do nothing.

"The place where we're standing is probably going to be under water if we don't do something right now," said Paul Birkeland, an organizer.

Environmentalists said it's a problem facing the entire world and the future generations.

"It really is a national security issue, a food security a public health issue, all those things are involved in global warming so we simply need to take action," said Maddie Axel, a demonstrator.

Demonstrators ended their march at Myrtle Edwards Park, where tents featuring various solutions to the warming problem were displayed.

Similar rallies were held in cities in all 50 states.

In New York, demonstrators gathered in lower Manhattan's Battery Park, overlooking New York Harbor, dressed in blue - some equipped with scuba gear and beach balls. The crowd gathered to form a Sea of People human line to symbolically mark New York's future coastline.

Scientists say a projected 10-foot rise in the ocean level caused by the melting of polar ice caps and glaciers will eventually flood Lower Manhattan and other low-lying coastal areas.

In one of the day's first demonstrations, skiers unfurled a protest banner in April snow on Whiteface Mountain near Wilmington, N.Y. Another group made an early morning hike to the summit of Maine's Cadillac Mountain, which is the first spot in the U.S. to be lit by the rising sun.

In Chicago's Daley Plaza, about 500 people listened to speeches from a panel of environmental experts who called for a reduction in carbon dioxide emissions. The crowd also waved signs exclaiming ''Step it up Congress.''

In Santa Monica, hundreds gathered along the Third Street Promenade just east of the Pacific Ocean to listen to lectures and listen to makers of ''green'' products pitch their wares.

The nationwide events were spearheaded by a group of students at Vermont's Middlebury College, who organized a campaign of blogs, e-mail messages and word of mouth communications.

"We see this to be the most pressing issue of our time, and our generation," said Will Bates, 23, one of six former Middlebury students who helped organize the event with author Bill McKibben, a scholar in residence at the college and among the first to write about global warming, in his 1989 book "The End of Nature."