WASHINGTON – “Global warming is indeed occurring, and it is undeniable that human actions had an impact on climate change,” Sen. Olympia Snowe, R-Maine, said at an international climate change summit Wednesday.

Snowe, co-chairwoman of the International Climate Change Taskforce, addressed initiatives to reduce greenhouse gas emissions and prevent a global temperature rise.

Maine is one of eight Northeastern states involved in the Regional Greenhouse Gas Initiative, aimed at reducing carbon dioxide emissions from power plants. California already has a law to slow the effects of climate change, Sen. Barbara Boxer, D-Calif., said at the summit, which spans two days.

“Maine is embracing the California emission standards,” Snowe said in an interview. “It’s a very forward way of thinking.”

The Regional Greenhouse Gas Initiative calls for power plants to cap carbon dioxide emissions at the current level of 121 million tons a year through 2015 as a step toward reducing emissions by 10 percent by 2020.

Because of melting ice caps, rising sea levels and increased carbon dioxide emissions, Boxer said, bipartisan support is needed from Congress to reduce the effects of global warming.

“We need to approach the issue with hope,” Boxer said. “We need to have the political will to get it all going.”

Snowe, who co-sponsored the Global Warming Reduction Act with Sen. John Kerry, D-Mass., also stressed the importance of bipartisan support.

“Time is not on our side,” Snowe said. “There is no question that we need to move forward in a timely fashion.”

The bill, which is before the Senate, would set targeted dates for greenhouse gas reduction to keep global temperatures from rising 2 or more degrees.

“Scientists suggest there is a [temperature] ‘tipping point’ beyond which they predict catastrophic environmental and economic events,” Snowe said.

International leaders, including Paul Wolfowitz, president of the World Bank, and, by video link, Angela Merkel, the German chancellor and current president of the G8 economic forum, attended the climate change session to discuss global warming initiatives.

The summit was held in a hearing room at the Russell Senate Office Building.