When Secretary Hillary Clinton sought to mobilize millennial voters, she held a rally with Al Gore in Florida and focused heavily on climate change.

On one level, this is a curious move. Al Gore’s presidential bid was in 2000, when very few millennials (a generation born between 1982 and 2000) were even old enough to vote. In addition, relatively few young people say “the environment and climate change” is the most important issue to them this year. And climate change has received almost no attention in the debates, nor much media coverage in major outlets.

So why focus on climate change as part of the final push to mobilize millennials, many of whom are still recovering from the emotional roller coaster of Bernie Sanders’ rousing but ultimately unsuccessful campaign?

To find the answer, I analyzed data from Tufts University’s Tisch College/CIRCLE Pre-Election Millennial Poll that explored millennials’ attitudes toward a variety of issues, institutions, movements and candidates.

The data show that climate change is one of the very few issues that most millennials can get behind this election season, even though it doesn’t rank as the top concern. Whether enough millennials will turn out in large numbers or influence the result of the election still remains to be seen. But the data show that climate change in the future has the potential to be a unifying issue across party lines, and one that millennials can directly connect to their personal lives.