In 1988, James Hansen delivered his now-famous congressional testimony on climate change, sparking the first mention of the impending problem in the presidential debate cycle that October. Here, you can watch as vice presidential candidates Lloyd Bentsen and Dan Quayle discuss climate change and fossil fuels:

Now, 24 years later, the science of climate change is well established. While 1988 was one of the hottest years ever recorded at the time, it’s been eclipsed in the past decades: 1998 is now the only year in the 20th century to make the list of the top ten hottest. Though fossil fuel consumption has continued unabated over the past decades, that didn’t stop candidates from discussing climate change during each and every debate season.

Yet this presidential debate cycle, the candidates was conspicuously mute on the topic. As the Washington Post’s Stephen Stromberg says:

Aided by the moderator’s questioning, they spent exactly no time on one of the greatest challenges the world’s governments must face, and foremost among them the United States’. This problem threatens the lives and livelihood of millions, particularly in poor countries, but, left unchecked, it also poses hazards to plenty of Americans and American interests. It will require possibly very expensive choices for developed and developing countries and delicate international negotiations. This challenge is climate change.

In 1988, soon-to-be Vice President Dan Quayle said, “It’s important for us to get the data in, to see what alternatives we might have to the fossil fuels and make sure that we know what we’re doing . . . The drought highlighted the problem that we have. And therefore, we need to get out of it, and in a George Bush administration you can bet that we will.”

George H. W. Bush’s administration fell short of that goal, but at least it was noted on the debate agenda as an issue with both a national and global scope. The Post concludes:

The Middle East is important. Pakistan is important. Iran’s nuclear ambitions are important. But so is climate change, and the debates should have reflected that.

More from Smithsonian.com:

The Political History of Cap and Trade

Does Climate Change Cause War?