Former Secretary of State John Kerry returned to the public spotlight Monday suggesting that the threat of climate change outweighs a nuclear attack from North Korea.

"A nuclear weapon overtly brandished in the hands of the wrong person, in the wrong country, receives significant focus and crisis management, and rightly so," Kerry said. "But a silent killer that compounds its destructive power daily and threatens the lives of literally billions of people with increasing destructive force is ignored and even mocked."

Kerry made the remarks in opening a two-day climate change conference at Yale University hosted by his Kerry Initiative. "This is not a partisan conference" because climate change is not a partisan issue, he said.

The event marked his return to the public spotlight after the 2016 presidential election. Kerry recalled that he was on a climate research trip to Antarctica on Election Day and quipped that he contemplated staying there after he heard Donald Trump had been elected president.

"I spent Election Day headed to Antarctica by way of New Zealand, and yes, the truth requires me to say that when we heard the results, we thought about staying in McMurdo Sound" in the frozen southern ice pack, he recalled.

"We came back because we know we have to continue to work towards the critical goal that we face," he added. "Despite what you hear from pundits ... there is nothing partisan about this threat.

But "sadly" climate change will be a problem for the next generation because politicians in Washington are ignoring its devastating effects, Kerry said.

"I have to say it. We are here, partly, to fill a void," Kerry said. "We're here because too many politicians who had the responsibility to defend our nation and the planet are hardly doing so by ignoring on the national level the devastating impact of climate change."

Kerry was joined for the opening session of the conference by former Obama administration officials including Ernest Moniz, the former energy secretary, and Jonathan Pershing, the former climate change envoy at the State Department.