Story highlights Obama said the US could not 'sit on the sidelines' as the planet heats up

The Obama administration brokered the Paris Agreement on climate change

Milan, Italy (CNN) Former US President Barack Obama praised his administration's record on climate change Tuesday, just as the Trump administration struggles with an internal rift over whether to pull out of the Paris climate accord.

The Paris Agreement was in part brokered by Obama and was seen as a major breakthrough after the previous accord, the Kyoto protocol, failed to include the US and China, the world's two biggest polluters.

US President Donald Trump vowed during his campaign to "cancel" US participation in the accord, which obliges countries to slash their greenhouse gas emissions to keep global temperatures from rising to catastrophic levels.

At a summit in Milan, Italy, focused on climate change and food availability, Obama defended the Paris Agreement and said that the US must show leadership and not "sit on the sidelines."

"During the course of my presidency, I made climate change a top priority because I believe that of all the challenges that we face, this is the one that will define the contours of this century, more dramatically perhaps than any other," Obama said at the Seeds & Chips summit