The issue

Former New York Mayor Michael Bloomberg, California Gov. Jerry Brown and other leaders representing more than a dozen states and hundreds of U.S. cities are in Bonn, Germany, this week to tell the world America is still on board with tackling climate change. The group just released a report that said if these non-federal entities were a country, their economy would be the third largest in the world. It also said the group represents nearly half of all Americans and more than half of the U.S. GDP.

The facts

The group largely represents America's coasts, where a lot of people live in big cities, but that's not where most of the greenhouse gases are emitted from coal, oil and natural gas production. The group represents up to 35% of America's total greenhouse gas emissions, according to the report's appendix data. That means this group represents roughly less than 5% of the world's emissions, despite comprising an economy that's the world's third-largest.

Why it matters

The report released here in Bonn is seeking to be optimistic, but it also concedes more action will be necessary. The biggest reductions would need to come from the fossil-fuel emitting states not currently on board.

The 35% figure -- not highlighted as part of the report's release -- underscores why federal action is essential in making sizable cuts in greenhouse gases. That's clearly going to be harder at a time when President Trump has said he intends to withdraw the United States from the Paris climate deal.