CNN held its “climate crisis” town-hall event Wednesday night, offering leading Democratic presidential contenders a chance to lay out their environmental prescriptions. CNN’s framing of the topic as a “crisis” reflects a slow but steady shift in how the press now describes climate change, but this changing vocabulary has yet to be embraced by the public.

The timeline below shows the prevalence of the terms “climate change,” “global warming” and “climate crisis” in English language books over the past two centuries, using Google Books. Not surprisingly, focus on the topic is relatively new, taking off only in the mid-1980s.

(For a larger view, click on the chart.)

Using data from the Internet Archive’s Television News Archive, processed by the GDELT Project, the timeline below shows the percentage of combined airtime on CNN, MSNBC and Fox News that mentioned the three terms by month since July 2009.

Three major trends can be seen in the graph above.

The first is that “climate change” and “global warming” were once used almost interchangeably, but “climate change” took over as the dominate term beginning in November 2012 and the reelection of Barack Obama to a second term. It continued to receive elevated attention during the next three years before falling out of favor somewhat during the 2016 presidential race and surging again in December 2016 following Donald Trump’s election.

The topic surged back into prominence in November 2018 as it became a major focus of the House elections and the rise of a new Democratic majority in the chamber.

Interestingly, in June of this year, “climate crisis” surpassed “global warming” in television mentions. The graph below shows why – mentions of “climate crisis” on CNN have skyrocketed, with MSNBC embracing the term to a lesser degree, while Fox News has only sparingly mentioned it.

To some media observers, this surge may be emblematic of journalistic "agenda setting.” We’ll let the data speak for itself.

Globally, looking at online news coverage in the 65 languages monitored by the GDELT Project back to January 2017, the numbers below resemble television’s, with climate crisis trailing the other two terms but steadily increasing in usage.

When it comes to the web-searching public, however, Google Trends data shows “global warming” was long the most-searched term, with “climate change” first edging it out in November 2016 with Trump’s election.

While the media increasingly favor “climate crisis” over “global warming,” the web-searching public does not appear to be registering the new term yet.

Looking only at “climate crisis” search trends, below, the phrase came into being with the release of Al Gore’s 2006 documentary “An Inconvenient Truth” and had largely disappeared from the public lexicon until last year’s election.

In the end, segments of the press are increasingly adopting “climate crisis” as the new term to describe climate change. That shift coincides with the Democratic House takeover last November, Democratic presidential candidates vying to demonstrate their bona fides regarding this issue, and perhaps news outlets’ deliberate embrace of a term conveying great urgency. But the public, at least so far, has yet to do the same.