Summit side-events have featured new climate pledges from corporations, investors, and nations, with more to come.
Ogden points to the suite of climate announcements emerging ahead of the summit, such as the recent White House effort with several big companies to cut emissions from strong greenhouse gases called hydrofluorocarbons used in refrigeration and air conditioning.
"At the end of the day, without being about the negotiations per se for a new climate agreement, all of this is very much wind at the back for countries and negotiators who have to ... begin the final sprint over the next year," Ogden said.
Between the march and various other events, the full spectrum of the climate movement is out in force. Activities range from the confrontational—such as fresh pledges by philanthropies to dump holdings in fossil fuel companies and a Wall Street sit-in—to corporate initiatives on green energy that include major companies like Ikea and insurance giant Swiss Re.
On Monday, the World Bank touted the growth in the number of businesses and national and regional governments supporting some form of carbon pricing, which is typically accomplished through an emissions-trading program or carbon tax.
According to the World Bank, there's support for some kind of pricing from 73 national and 22 state, regional, and local governments that jointly comprise 54 percent of global greenhouse gas emissions. There is also support from more than 1,000 companies, such as Lego, Dupont, Nestle, and Shell Oil.
On a call with reporters last week, Obama administration officials said there will be a new partnership with six oil companies to cut emissions of methane, a major greenhouse gas.
Paul Bledsoe, a senior fellow on climate at the German Marshall Fund of the United States, said this week's events in New York show that the United Nations has learned that it needs to rally public support to make the diplomatic process work.
"Clearly a major goal of the summit is to rally public attention to the need for near-term climate action leading to a global agreement," he said. Galvanizing a popular movement is something that Bledsoe says the U.N. has done a lousy job of in the past, but he calls the U.N. leader's decision to take part in environmentalists' big march on Sunday a noteworthy change.
"Ban Ki-moon's participation in the march is a clear recognition of the need for popular support," said Bledsoe, who was a climate-policy aide in Bill Clinton's White House.
Tuesday's summit will unfold against fresh evidence of the failure of global leaders thus far to stem soaring greenhouse gas-emissions. The research group called the Global Carbon Project released findings Sunday showing that worldwide carbon emissions from burning fossil fuels grew 2.3 percent to reach a new record in 2013, with 2.5 percent growth projected this year.