The international effort to fight climate change is about to get injected with a bit of Hollywood flash, a lot of Wall Street green, and a considerable dose of cheerleading rather than dry treaty negotiations.

Business leaders, mayors, governors, and activists from around the world gather this week in San Francisco for the Global Climate Action Summit, where participants will trumpet what they’ve done and announce new efforts to slow a warming world.

In addition, a smattering of celebrities such as musician Dave Matthews and actor Alec Baldwin will add a touch of red carpet feel to the summit, which starts Wednesday.


It will involve trillions of dollars of pledges for spending on cleaner energy and getting out of investments in heat-trapping fossil fuels, according to officials involved. And it will include a newer way of fighting climate change by emphasizing more climate-friendly land use, food production, and diets, along with massive increases in forests — something one expert called ‘‘the forgotten climate solution.’’ Cities, states, businesses, and charitable foundations are all going to get in the act.

‘‘It’s a bit like a game show,’’ said summit communications director Nick Nuttall. ‘‘It’s going to be loads of Hollywood style announcements.’’

And when you are talking about shifting trillions of dollars to finance initiatives, the private sector needs to get involved and that’s happening, said Nigel Purvis, chief executive officer of the non-profit Climate Advisers and a former climate negotiator in the Bill Clinton and George W. Bush administrations.

‘‘This is the climate action summit, emphasis on the action,’’ Purvis said. ‘‘Despite the lack of leadership from Washington, it’s really about action.’’

But so far such pledges have produced more talk than action, said Angel Hsu, an environment professor at Yale University and the National University of Singapore. She is the lead author of a United Nations report released Monday on what businesses, states, and local governments can do and already have done.


That report says businesses and lower levels of government have the potential to cut enough greenhouse gases emissions to keep global warming below the danger point of another 2 degrees Fahrenheit from now. However, the same report says so far, 8,000 pledges from those groups haven’t accomplished much.

To keep from hitting that 2 degree mark, the world has to cut its expected annual emissions by nearly 15 billion tons of carbon dioxide equivalent by 2030, including what’s pledged in the 2015 Paris climate agreement. The businesses and states basically get about 4 percent there, according to Hsu.

‘‘It’s not much,’’ she said. ‘‘We were actually shocked to find that the numbers were so low.’’