In 1989, cartoonist Matt Groening told a reporter that his new television show, “The Simpsons,” would tackle the serious subjects in life.

“It always amazes me how few cartoonists in print or animation go after the bigger issues, the kinds of things that keep you lying awake in the middle of the night,” Groening said, as reported in “Planet Simpson: How A Cartoon Masterpiece Defined A Generation,” a 2004 book about the show by journalist Chris Turner.

Groening’s creation, an animated series about the yellow-colored, often-vulgar Simpson family, went on to become the longest-running American sitcom. Since its debut, the series has aired more than 475 episodes and racked up more than 20 Emmy Awards.

True to Groening’s intention, the show has frequently used biting satire to examine societal problems, including climate change. Its characters visit the rapidly melting Springfield Glacier, deliver chilling proclamations about rising temperatures and flooding lowlands, and speculate that global warming concerns are baseless.

In a typical treatment of the subject, Homer Simpson and his daughter Lisa argue about the implications of a snowfall ( “O Brother, Where Bart Thou?”, air date December 13, 2009 ). At eight years old, Lisa is a thoughtful, precocious child. As the show’s most prominent activist, she often clashes with her father, the buffoonish Homer.

HOMER: Gee, Lisa, looks like tomorrow, I’ll be shoveling 10 feet of global warming.

LISA: Global warming can cause weather at both extremes, hot and cold.

HOMER: I see. So you’re saying warming makes it colder. Well, aren’t you the queen of crazy land! Everything’s the opposite of everything!

(Homer dances, twirling and waving his arms.)

HOMER (singing): La de da de da. I’m Lisa Simpson! La de da de da!

LISA (muttering): Really? Really?

“The Simpsons” is so popular that its characters serve as a common language through which society discusses the world, said Turner, the “Planet Simpson” author, in a recent interview. Many Americans — and indeed many people around the world — know the meaning of “D’oh!,” “Don’t have a cow, man” and “Mmm … donuts,” even if they don’t remember that the phrases originated with the series.

Because of its popularity, the show reaches a larger audience than many journalists and scientists, said Tim Delaney, author of “Simpsonology” and professor of sociology at the State University of New York at Oswego. Meanwhile, its humorous approach may disarm viewers who would otherwise dismiss messages about the environment. “Funny is funny,” he said. “Everyone can laugh at it.”

‘A Microcosm of America’

When the show addresses climate change and other environmental problems, it generally does so through the character of Lisa Simpson.

As Turner reports in “Planet Simpson,” key members of “The Simpsons” creative team identify closely with Lisa’s political beliefs. Writer George Meyer, like Lisa, is a vegetarian and an environmentalist. Producer Al Jean put it this way: “The character we’re closest to is Lisa Simpson, a character who reads a lot and hopes for a better life.”

In her crusades, Lisa frequently meets resistance from the apathetic and disdainful residents of Springfield, the fictional city in which the Simpson family resides.

In “The Simpsons Movie” (2007), Lisa canvasses her neighborhood, warning people of increasing water pollution in the Springfield Lake. But her neighbors slam doors in her face. When Lisa delivers a speech — titled “An Irritating Truth” — about the lake’s water quality, the local newspaper describes her as a “pushy kid” who is nagging the town.

In the television show’s earliest mention of climate change, news anchor Kent Brockman expresses a lackadaisical attitude toward a spate of warm winter weather ( “Mr. Plow,” air date November 19, 1992 ).

“Could this record-breaking heat wave be the result of the dreaded greenhouse effect?” he asks. “Well, if 70-degree days in the middle of winter are the ‘price’ of car pollution, you’ll forgive me if I keep my old Pontiac.”

Brockman’s comments likely resonate with many East Coast residents experiencing this winter’s harsh weather, said Tony Broccoli, a climate scientist at Rutgers University. No matter the potential hazards of climate change, “the prospect of a warmer world may not seem so bad on cold, snowy days,” he said. “For people living in relatively cold climates, the word ‘warming’ does not necessarily have a negative connotation.”

In a 2005 episode, Lisa again sounds the alarm, this time in a speech to her classmates about the rapidly melting Springfield Glacier ( “On a Clear Day I Can’t See My Sister,” air date March 6 ).

LISA: Listen, people, how can you stand there eating snacks and being children when the world’s glaciers are vanishing? We have to do something about it. Glaciers are nature’s alarm clock, and it’s time for us to wake up. Can there be any doubt that the culprit is greenhouse gas, produced by man?

(At that moment, Lisa’s classmates hear a fart sound. It comes from a walkie-talkie that Bart, Lisa’s bratty older brother, has placed in her backpack. The students titter.)

BART: The only gas is coming from Lisa’s butt!

In their indifference to Lisa’s warnings, Springfield residents mirror the attitudes of many Americans. A Gallup poll last March found that 48 percent of Americans believe that the threat of climate change has been exaggerated. Meanwhile, two-thirds of those polled believed that climate change would not affect them. (On the other hand, in several polls last summer, a majority of Americans reported support for federal legislation to address the issue.)

Back at the Springfield Glacier, Lisa confronts a park ranger who denies the existence of climate change.

RANGER: Young lady, the federal government’s position on global warming is that it does not exist. This glacier’s doing just fine.

LISA: No, it isn’t. It’s a lump of slush. Look at it!

(Later, Lisa falls in a pool of meltwater created by the disintegrating glacier.)

LISA: Help, I’m sinking in the lake!

RANGER: You mean, you’re walking on the glacier!

This scene satirizes the federal government’s reluctance, at times, to acknowledge the reality of climate change. In addition, it “reminds us that attitudes about climate change have become politically polarized to such an extent that many policymakers and citizens are skeptical about human-induced climate change, despite very strong evidence,” said Broccoli, the Rutgers scientist.

“Springfield is supposed to be a microcosm of society, especially the Simpson family itself,” said Delaney, the sociologist and “Simpsonology” author.

In Delaney’s reading, members of the Simpson family symbolize positions across the spectrum of American political beliefs. The stubborn and contemptuous Homer represents climate deniers. His son Bart, a nihilistic troublemaker, symbolizes people who are apolitical or otherwise disengaged from the issue. Mother Marge, who often mediates family disagreements, stands in for the moderate position, expressing concern about climate change but little personal engagement. Finally, Lisa represents the segment of the American public that is alarmed and active on the issue. (Watch Marge comfort Lisa about global warming. )

Take on Climate Change ‘Pretty Weak’

Turner, the “Planet Simpson” author, has argued that the Golden Age of “The Simpsons” occurred between 1992 and 1997. During that period, the series peaked as an original and clever critique of American society. Since that time, the show’s writing has become less nuanced and more reliant on obvious gags. That is, the quality of the writing declined just as climate change was rising to prominence as a social and political problem.

One result has been that “The Simpsons” writers have relied increasingly on stereotypes of environmentalists. In recent years, Lisa has been characterized as a shrill doomsayer. In a 2009 episode, she delivers a horrifying class presentation about the future of Springfield ( “The Good, the Sad and the Drugly,” air date April 19 ).

LISA: There is no Springfield 50 years in the future! With global warming trapping the CO2 inside our poisonous atmosphere, our super-heated oceans will rise, drowning our lowlands, leaving what’s left of humanity baking in desert that once fed the world. And in the new Nineveh, darkness falls.

(Lisa’s classmates gape at her, terrified. One boy screams and throws himself out the window.)

Of more than 475 episodes aired, “The Simpsons” has mentioned climate change in fewer than 10. References to the issue are brief, often consisting of scenes of only a few seconds. In contrast, the show has lavished attention on other issues, Turner said. The nuances of religious belief, the dangers of nuclear power, and the excesses of capitalism, for example, have been explored consistently throughout the series.

“Their take on climate change has been pretty weak,” Turner said.

“That’s a bit of a shame, because if there is anywhere that climate change could get a great hearing in pop culture, it would be in ‘The Simpsons.’”

Research Methodology

To identify episodes of “The Simpsons” that reference climate change, episode transcripts and detailed summaries were obtained from several fan sites: Simpson Crazy, The Simpsons Archive and Simpsons Wiki. The transcripts and summaries were downloaded using a Firefox browser extension called “DownThemAll!” , with which a user can download all of the hyperlinks contained in a Web page. Episode summaries and transcripts were saved as HTML files to a designated folder on a computer. Next, the Macintosh “spotlight” function was used to search the folder for the key terms “greenhouse effect,” “global warming” or “climate change.” The spotlight function created a list of episodes containing any of those terms.

Complete episode transcripts were available only for the show’s first 13 seasons. Episode summaries were available for all of the seasons; but it is possible that a passing reference to climate change would not be included even in a detailed summary. Therefore, in reporting this story, Peach registered for a Simpsons trivia forum and posted a question asking forum users to name episodes relating to climate change. Users named several episodes that had not been identified previously.

Additional episodes referencing climate change were also identified through search engine searches for “The Simpsons” and the key terms mentioned above: “greenhouse effect,” “global warming” and “climate change.” If readers know of any Simpson episodes relevant to this story that we missed, we hope they’ll let us know about them.

Sara Peach is the editor-in-chief of Yale Climate Connections. She is an environmental journalist whose work has appeared in National Geographic, Scientific American, Environmental Health News, Grist,...