Still jet-lagged from a weekend trip to Sudan to discuss civil relations within the wartorn nation, Senator John Kerry ’66 had no time to rest in New Haven.

[ydn-legacy-photo-inline id=”5813″ ]

Kerry, the Senior Senator from Massachusetts and Chairman of the Senate Foreign Relations Committee, spoke to packed rooms in back-to-back talks Monday night at a Yale Political Union debate on climate change and a talk on nuclear nonproliferation sponsored by the Yale chapter of Global Zero, an international initiative to eliminate nuclear weapons.

Kerry, who was a member of the Liberal Party and president of the YPU in his junior year at Yale, called on the 250 people present at the debate in Sterling-Sheffield-Strathcona Hall to take action against climate change.

Students, he said, play a major role in bringing about political change on a wide range of issues, including the two he discussed, environmental protection and global arms control.

“You’re students at Yale, but you also have another responsibility,” Kerry said during his speech at the YPU. “Every time major change has occurred, it has been because students like you decided to get involved and make a difference.”

At both the YPU debate and the Global Zero talk in Linsly-Chittenden Hall, he used an example of student activism from his own college years. Kerry recalled students boarding buses on York Street bound for the American South. The students, he said, were taking part in the “Freedom Rides” to encourage African-Americans to vote and fight against Jim Crow laws During the Global Zero event, he pointed to the conclusion of the Vietnam War and the women’s rights movement as other examples of students effecting positive change.

Kerry said he has total confidence in the scientific evidence behind global warming. But even if this evidence were false, he said, the economic and diplomatic benefits of curbing greenhouse gas emissions are worth the effort.

Kerry said the United States’ delay in tackling climate change could hurt its global standing and could hinder economic recovery after the recent recession. Countries such as China, he said, are outspending the United States in the research and development of energy-efficient technology. He added that the untapped potential of this market, and alternative energy, is critical to development both at home and abroad. The United States will be unable to recruit developing countries to help protect the environment if it cannot curb its own pollution, he said.

“If we don’t lead the world in environmental policy, we won’t lead the world in any other policy,” he said.

Leaving the YPU debate in SSS, Kerry rode across campus in a Chevrolet Suburban to join former President of Mexico Ernesto Zedillo — now director of the Yale Center for the Study of Globalization — at LC for the Global Zero talk.

At the talk, Kerry and Zedillo said that the world’s governments must continue nuclear disarmament efforts. Zedillo discussed the United States and Russia’s New Strategic Arms Reduction Treaty, or New START, an offshoot of the 1991 START treaty. Both of these agreements are bilateral nuclear disarmament treaties between the United States and Russia. If ratified, Kerry and Zedillo said, the New START treaty will reduce the number of deployed strategic nuclear warheads from over 2,000 to around 1,550.

Zedillo said that while countries still own nuclear arms, the fear that they will be accidentally deployed or otherwise misused will persist. Kerry added that of the United States’ primary concerns regarding nuclear disarmament is “threat perception.”

“People, some of them in Washington D.C., would look at you and say ‘Hey, you’re crazy. We’re not going to disarm so some terrorist can come in and attack us,’” Kerry said.

While no one can guarantee that disarmament will not lead to increased vulnerability, Kerry said, every step taken toward disarmament will bring the world closer to a different style of conflict resolution. He said he believes that much of the US’s inability to effectively deal with nuclear disarmament stems from an ancient ideological struggle in Washington D.C.

“It’s a matter of orthodoxy to disagree with [the New START treaty],” Kerry said. “It’s the same orthodoxy that kept a single Republican from signing on to the climate energy bill.”

Eric Willett ’14 said he thought Kerry seemed very frustrated with the current political climate at the Global Zero talk, adding that Kerry appeared to see partisan politics as an obstacle in the treaty’s path to ratification.

Kerry said he was surprised by the student turnout at the discussion, where about 150 students packed a lecture hall and some had to sit on the floor or in the aisles.

All three students interviewed after the YPU talk said they were impressed with Kerry’s speech overall. Still, some suggested Kerry did not fully rebut counterarguments.

“I still felt like the actual opinions on the resolution didn’t shift that much,” said Elias Kleinbock ’14. “It was also frustrating to hear Kerry evade so many points, like [a question about] how leading the world [in environmental policy] could incur massive costs.”

The Senate Foreign Relations Committee approved the New START treaty on Sept. 16 but it has yet to be approved by the entire Senate.