In recent weeks, students at Harvard have stepped up the pressure on the university to divest its $32.3 billion endowment – the largest in the world – from the fossil fuel industry. In a display being mirrored on campuses across the country, students blocked the entrance to the president’s office in a coordinated effort that led to the arrest of one student. But the administration has so far yielded nothing, refusing to even hold an open forum about divestment with the university’s main governing body. In 2013, university president Drew Faust sent a letter to the Harvard community insisting that divestment would “have negligible financial impact on the affected companies” and would “diminish the influence or voice we might have with this industry.” Last month, Faust sent another letter effectively doubling down on the university’s stance while plugging a handful of modest new initiatives.

Still, the divestment movement has continued to gain steam and grab headlines. But the Harvard administration’s reluctance is not rare. In fact, just 11 U.S. colleges have committed to pursue divestment from all fossil fuels. The hope of Divest Harvard, the student-run organization at the center of the campaign, is that success at an institution as prominent as Harvard will be the sort of high-profile catalyst that other campus efforts across the country need. But while a worthy argument for divestment can be made on environmental and ethical grounds, the movement would benefit from a shift in focus. The economics of divestment, it turns out, can be a far more effective motivator.

The full economic costs of climate change continue to crystallize, with recent research showing that the social cost of carbon is much higher than previously believed. And the most accurate estimates still do not incorporate the damages resulting from sea level rise, ocean acidification, and natural disasters because those risks remain too difficult to quantify. The economic argument for fossil fuel divestment, more specifically, centers on the concept of a “carbon bubble”, which asserts that fossil fuel-based assets are grossly overvalued and could potentially result in stranded assets on the scale of trillions of dollars. The overvaluation is due to the fact that much of the existing coal, oil, and gas reserves will have to stay in the ground in order to stay within the global carbon budget (i.e. the emissions cap that would limit warming to the internationally agreed upon threshold of 2°C above preindustrial levels). In fact, just 20 percent of known fossil fuel reserves can be burned if we are to avoid 2 degrees of warming, according to the Carbon Tracker Initiative, a London non-profit organization. And a new report finds that, for the top 200 publicly traded fossil fuel companies, the estimated emissions potential from listed reserves exceeds those companies’ share of the carbon budget by over 400 percent. So, in order to avoid catastrophic climate change, the majority of corporations’ reported coal, oil, and gas reserves are, in any rational sense, unburnable.

The likelihood of fossil fuel investments becoming stranded assets lends merit and urgency to the divestment movement. And though campus-based efforts have struggled to make headway, action is being taken on other fronts. The calls for divestment, once dominated by grassroots environmental activists, are beginning to reverberate from campus quads to Beacon Hill all the way to Wall Street. In the Massachusetts legislature, Senate bill S. 1225 would make the Commonwealth’s pension fund the first in the nation to divest from fossil fuels. In January, 17 foundations controlling almost $2 billion pledged to divest, joining a growing group of religious institutions citing the morality of environmental stewardship. And last month, the Natural Resources Defense Council (NRDC), in collaboration with BlackRock and FTSE Group, announced the launch of the first stock market index to exclude companies linked to fossil fuel extraction in an effort to “jumpstart mainstream climate-conscious investing.”

All of this progress suggests that there may be a light at the end of the tunnel for campus-based divestment efforts. And for Harvard, there are no signs that the movement will soon fade. Three days after President Faust’s most recent statement, a group of about 120 faculty members published an open letter calling for divestment. And last week, Stanford University announced that it was divesting its $18.7 billion endowment from coal companies. With the world’s fourth largest endowment, Stanford will become by far the largest university to commit to coal divestment, and the board of trustees hinted that action on oil and natural gas may still be yet to come.

But still the question remains: does divestment even matter? After all, only a fraction of Harvard’s $32.3 billion endowment is actually invested in fossil fuels – far too little, as Faust has said, to have a noticeable impact on the bottom lines of multi-billion dollar energy corporations. But that’s not the point. When waves of charitable foundations, faith-based organizations, and prestigious universities begin to make the choice to disassociate with an entire industry, a shift in the public’s perception of that industry will follow. Some opponents of divestment have denounced the movement as an effort to “stigmatize” the primary source of the world’s energy, but that is exactly what’s needed. Coal, oil, and gas companies should be cast in the same harsh light as the subjects of successful divestment movements that preceded this one – apartheid and tobacco, in particular. In the end, the most meaningful result of divestment will not be any immediate economic impact, but a lasting political message with the potential to move the needle on public opinion about fossil fuels.

John Prandato is the Manager of Online Communications and Outreach for MassINC, the think tank that publishes CommonWealth.