From the website:

The Stop Global Warming Virtual March is a non-partisan effort to bring citizens together to declare that global warming is here now and that it is time to demand solutions. Global warming is the most urgent issue of our time, and while the problem is of worldwide significance, we recognize that the United States is the biggest emitter of greenhouse gases, responsible for 40% of the industrialized world's emissions, and doing the least about it. The necessary first step must be to encourage Americans to take action. This online grassroots movement is about change -- as individuals, as a country, and as a global community. We are all contributors to global warming and must all be part of the solution.