CHICAGO -- Former President Barack Obama popped in to Mayor Rahm Emanuel's mayoral climate summit on Tuesday, saying it can be challenging to address climate change "in an unusual time" but never mentioning President Donald Trump by name.
The former president's Chicago appearance also gave a boost to his former chief of staff as Emanuel ramps up to run for a third term as mayor.
Obama was in town for a private speech later in the day and talked to mayors in attendance at the downtown climate event for about 15 minutes. Though Trump's pulling the U.S. out of the Paris climate agreement prompted mayors to take steps to limit greenhouse emissions themselves, Obama stepped around criticizing Trump directly.
Instead, the former president tried to show a path toward fighting climate change without Trump's cooperation.
"Obviously we're in an unusual time when the United States is now the only nation on earth that does not belong to the Paris agreement," Obama said. "And that's a difficult position to defend. But the good news is that the Paris agreement was never going to solve the climate crisis on its own. It was going to be up to all of us."
Reciting a litany of recent extreme weather events he said are evidence of climate change, Obama also mentioned the aftermath of Hurricane Maria's devastation of Puerto Rico, a recovery effort for which the Trump administration has drawn criticism.
"A conveyor belt of some of the strongest hurricanes on record this summer smashed into Houston, and Florida and Puerto Rico, and more than two months later they are still struggling to recover," he said.
And Obama called on American voters to "make it a prerequisite for the vote for anybody for elected office that they're paying attention" to global warning. His remarks Tuesday are in keeping with Obama's general policy of not engaging directly with Trump since the new administration took over in Washington, D.C.
While Obama stuck to talk about the environment, Emanuel placed Trump front and center at the event by pointing out he has opted the U.S. out of the Paris climate accords.
The preamble to the Chicago Climate Charter the participating mayors signed on Tuesday read: "President Trump's decision to withdraw the United States from the Paris Agreement spurred over 380 cities in the U.S., numerous cities in other parts of North America, and countless organizations worldwide to commit themselves to the Agreement."