Late Saturday night, delegates from 195 countries around the world attending the COP21 conference agreed to a historic climate deal to reduce greenhouse emissions.

On the ground in Le Bourget—the small community northeast of Paris where the conference was held—the mood was celebratory.

"There's a green hangover in Paris," said Charlie Sennott, head of The GroundTruth Project, who joined Boston Public Radio live on the line from the City of Light. "This was really met with tremendous joy."

Sennott said the conference hall erupted with cheers after the news of the accord was announced.

"You have to imagine a conference where there are 40,0000 people in attendance...the place just erupted in cheers. The heads of state who were there, Secretary of State John Kerry, people from every corner of the world, the guys in the printing room printing out the documents, the people serving food, the security guards, the whole world was in this convention center cheering," Sennott said.

That jubilation could be chalked up partially to the historic nature of the agreement, but Sennott said something else was also at play: the defiance of a city returning to form after a series of terrorist attacks just weeks earlier.

"This was a historic achievement, to create this agreement. But there was also something here about the mood...," he said. "Pair was so hit by the terrorist attacks, so darkened by that, and its spirit was really challenged."

"This was a chance to really celebrate," he continued.

To hear more from Charlie Sennott, tune in to Boston Public Radio above.