Secretary of State John Kerry called climate change a threat to national security and urged international collaboration in the fight against global warming during a diplomatic tour of Asia this week.

“Climate change can now be considered another weapon of mass destruction, perhaps the world’s most fearsome weapon of mass destruction,” Kerry said in an address delivered in Jakarta, Indonesia, on Sunday. “Think about the proliferation of weapons of mass destruction. It doesn’t keep us safe if the United States secures its nuclear arsenal, while other countries fail to prevent theirs from falling into the hands of terrorists. We all have to approach this challenge together.”

The secretary of State said during the speech that while the U.S. is taking steps to rein in carbon emissions, developing nations must also curb air pollution.

“It is time for the world to approach this problem with the cooperation, the urgency, and the commitment that a challenge of this scale warrants…. It’s not enough for one country or even a few countries to reduce their emissions when other countries continue to fill the atmosphere with carbon pollution as they see fit,” he said.

Don’t expect Kerry to stop talking about climate any time soon. Aides say the secretary of State is slated to deliver a series of speeches stressing the urgency of climate action this year.

Kerry reiterated calls for greater collaboration in the effort to mitigate climate change during a press conference Monday with Indonesian Foreign Minister Marty Natalegawa. He was also forced to defend the U.S. against criticism that it lacks authority to push for international action on climate change in light of its failure to ratify the Kyoto Protocol, an internationally binding global-emissions treaty.

“On the subject of climate change and the international conventions, actually the United States of America is taking a lead today,” Kerry said. “President Obama has decided that he will do, by executive order, what Congress has been unwilling to do … [and] we have lowered emissions in the United States significantly.”

During the press conference Kerry also touted a pledge made by the U.S. and China to reduce greenhouse-gas emissions announced on Saturday.

Kerry’s heavy emphasis on climate change comes as the administration mulls a final decision on the Keystone XL pipeline. Obama has said he will not approve the pipeline if it significantly adds to the amount of greenhouse gases in the atmosphere.