This coming Saturday, April 14 marks Step It Up 2007, the first National Day of Climate Action. There will be more than 1,300 gatherings across the country, from big rallies that aims to draw thousands, to modest global-warming awareness events organized by small groups of concerned citizens.

Big and small, all of them will be calling on Congress to cut carbon emissions 80 percent by 2050. Though such a cut wouldn't reverse global warming, it's thought to be enough to fend off the most catastrophic effects.

As we reported here Friday, the latest study summary released by the Intergovernmental Panel on Climate Change documented a host of serious problems already being observed due to the warming global climate. They include mountain avalanches, declining water quality, crop damage and increased flooding. Poor communities are especially vulnerable to warming's negative effects, according to the IPCC.

Step It Up's Vermont-based organizers hope the nationwide events will help spark the movement necessary to bring about fast change, writes leader Bill McKibben, a noted environmentalist and author:

If we're going to make the kind of change we need in the short time left us, we need something that looks like the civil rights movement, and we need it now. Changing light bulbs just isn't enough.

Some of the events will be held in iconic places across the South. For example, more than a dozen organizations are working to organize the national kickoff of "Step It Up" on Friday, April 13 in New Orleans. The "Save New Orleans -- Stop Global Warming" rally will begin at 5:30 p.m. on the Lower 9th Ward levee in the city's Holy Cross neighborhood, which was devastated by Hurricane Katrina.

That same day, organizers in Fort Worth, Texas will protest the financing of proposed new coal-burning power plants in the state at a JP Morgan Chase branch. They drew their inspiration from the Rainforest Action Network's Global Finance Campaign, which works to stop Wall Street from funding environmentally destructive practices, including the TXU coal project.

Also on Friday, the documentary film "Everything's Cool" will make its Southeast premiere at the Full Frame Film Festival in Durham, N.C. After the screening, Step It Up organizers will invite the audience to participate in the "Stop Global Warming Rally" to be held on the state capital grounds in Raleigh the following day.

And in Key West, Fla., the group Reef Relief is organizing an outing to the offshore coral reef on Saturday morning. Once there, they'll dive the reef and stand underwater displaying signs against global warming while being filmed by underwater videographers.

Besides the demand to reduce U.S. carbon emissions 80 percent by 2050, something else uniting all the various actions is a sense of urgency. As McKibben observes:

The best science tells us we have ten years to fundamentally transform our economy and lead the world in the same direction or else, in the words of NASA's Jim Hansen, we will face a "totally different planet," one infinitely sadder and less flourishing.

The recent elections have given us an opening, and polling shows most Americans know there's a problem. But the forces of inertia and business-as-usual are still in control, and only our voices, united and loud, joyful and determined, can change that reality.

Please join us.