Fossil fuel corporations have made a powerful enemy—and he can “Do the Math.”

Bill McKibben, author and co-founder of 350.org, a climate activism website, spoke Nov. 28 at the Athenaeum Theatre, 2936 N. Southport Ave., as part of his nationwide “Do the Math” tour that serves as a call to action to stop environmental degradation caused by oil, gas and coal companies.

Chicago was the 15th stop on the 21-city tour that culminates Dec. 3. According to McKibben and his colleagues, they hoped the tour raise environmental awareness to the next level and motivate people to take action against companies that are allegedly destroying the planet.

“We know what we are facing as a species; it is scary, but it excites me,” McKibben said. “I’m excited because now we know what we need to do, and as of tonight, we are going after the fossil fuel industry.”

The goal of the tour was to convince universities and business owners to divest holdings in the fossil fuel industry as a first step to disrupting its business practices rather than scare and shame people into being eco-friendly, he said.

“If they’re willing to wreck the future, then we’re going to try and take some of [the industry’s] money,” McKibben told the crowd. “Some of you [may have] to sit in jail before it’s over, too.”

McKibben said, the idea for the tour came after he and his colleagues led the largest civil disobedience movement of the last three decades in Washington, D.C.

According to McKibben, more than 1,200 people were arrested for peacefully protesting the Keystone XL oil pipeline, a proposed project extending from Alaska to Texas that has garnered negative attention because of its environmental impact. Approval of the pipeline has since been delayed.

The tour featured an array of speakers, both in person and on video, who rallied audience members against fossil fuel companies and commended activists on their work. Speakers included author and activist Naomi Klein, 1984 Nobel Peace Laureate Desmond Tutu, documentarian Josh Fox, glaciologist Jason Box and the Rev. Lennox Yearwood, president of the Hip-Hop Caucus, a civil and human rights organization.

Klein called students the “leaders of the movement” and agreed with McKibben that college campuses are where voices will be heard the most. Both Klein and McKibben noted that many colleges have worked to build sustainable buildings and alternative independent energy sources, but asserted that these advances are not enough. Both said the next step should be divesting in companies that sell holdings in fossil fuels.

“If you’re going to green the campus, then why not green the portfolio too?” Klein asked.

Tutu addressed audiences with a video message that compared the current environmental movement to the achievements of activists who helped abolish apartheid in South Africa three decades ago. He said that the current movement is  global and has millions of members.

“This is about our future,” he said. “It is about the existence of humanity.”