Amber Sullins gets a minute or two to tell up to two million people about some extremely complicated science, using the tools of her trade: a pleasant voice, a green screen, and small icons denoting sun, clouds, rain, and wind.

She is the chief meteorologist at ABC15 News in Phoenix, so her forecasts mostly call for sunshine. Within this brief window, however, Sullins sometimes manages to go beyond the next five days. Far beyond.

"We know climate change could affect everything about the way we live in the future, from agriculture and tourism to productivity and local business," she once noted. "But at what cost?"

The answer came from a University of Arizona economist whose work is meant to improve understanding about how climate change may affect markets. "Weather will become more variable," he replied, "and that will then act to make [gross domestic product] more variable. So we'll bounce around more, from year to year."

It was a 35-second segment in a nightly newscast, a mundane moment preceding reports about three fallen firefighters in Washington state and a dangerous development for air travelers.

But that climate-focused scene, and hundreds of others like it playing out at local news stations across the country, marks a major shift in the way Americans hear about climate change. The safe and familiar on-air meteorologist, with little notice by viewers, has become a public diplomat for global warming.

Your local news forecaster is the face of what the National Weather Service estimates is a $7 billion weather-prediction industry, a largely invisible operation that stretches across some 350 public- and private-sector organizations in the U.S.

At its center are the 5,000 employees of the National Weather Service, whose efforts at forecasting generate about $32 billion in annual benefits to American households, according to federal estimates.

Broadcast television still commands enormous attention within the U.S. weather industry, even at a time when the curious can summon the temperature and forecast by pulling a device out of their pockets. But weather apps haven't digitized weather prediction.

Despite the hype about artificial intelligence, it still takes an actual human to predict the weather — and, for millions of people, there's just no substitute for a photogenic and trustworthy meteorologist.

Two-thirds of 18- to 64-year-olds in the U.S. watch a news broadcast, either on TV or a digital device, at least once a week, according to 2015 research by the market research company SmithGeiger LLC. Nearly 40 percent of people within this wide age group watch broadcast news on daily basis, and the reliable presence of an on-air meteorologist is a huge part of the draw.

"Local TV news wouldn't exist any more if it weren't for the weathercasts," says Ed Maibach, director of George Mason University's Center for Climate Change Communication.

The weatherman or weatherwoman is the only scientist most people ever see. TV meteorologists tend to be inviting, attractive figures who together have earned the trust of millions of people. That's why the American Meteorological Society has for years encouraged them to embrace their default role as "station scientist."

It's difficult to say how climatologists come across and what they look like because few have ever been spotted in the wild. And when climatologists do show up on television, perhaps in a drab C-SPAN broadcast of a congressional hearing, they can be greeted with a partisan hostility that the weather forecaster never faces — even when one fails to foresee a thunderstorm heading for Phoenix. ("They are much more difficult to forecast than, say, a winter storm coming in," Sullins says.)

Still, public skepticism about climate change is a reality faced by television forecasters, who need to have the broadest appeal possible. Denialism is "an American phenomenon," says veteran Miami weatherman John Morales, who is now at NBC 6. "This is not something you see around the world."

This American reluctance to embrace scientific evidence hasn't often been counteracted by broadcast meteorologists — who are, in fact, no more likely than the average citizen to agree that climate change is caused by humans.

There are plenty of possible explanations for this outcome, including a shortage of climatology education within meteorological training programs.

Part of meteorologists' reluctance to talk about the climate stems from the treacherous tools of their trade. Meteorologists learn very quickly that weather models are messy. Some no doubt sour on finicky climate models because of this experience.

If short-term weather models make mistakes, it may seem reasonable to assume that a model projecting into the next century is ridiculous.

"Meteorologists are used to looking at models and being burned," says Paul Douglas, a former TV weatherman-turned-serial entrepreneur, who recently published a book on climate change and faith.

Sullins, 34, knows there's tension in telling her viewers about conditions in the 22nd century when she is reluctant to commit to a two-week forecast. "I can't tell you what the high temperature is going to be on July 4 of this year, today," Sullins says. "I can't possibly tell you that. But I can tell you, based on climate, that in July, here in Phoenix, it's going to be over 100 degrees. That's easy."

Her point is that weather and climate are "two entirely different beasts." It's like the difference between someone's mood and disposition, Sullins says. She wants viewers of the nightly news to spend more time thinking about the planet's disposition.

There are about 500 broadcasters like Sullins and Morales, who each receive regular data dumps and ready-to-use graphics from Climate Matters, an organization whose mission is to turn TV meteorologists into local climate educators.

The program was founded in 2010 by Climate Central, a research-and-journalism nonprofit, with help from George Mason University, the American Meteorological Society, and others. Newscasters who participate are sent possible topics for climate-related segments every week, with TV-ready data and graphics pegged to large-scale meteorological events, such as unusually high heat or precipitation, local trends, or seasonal themes.

"Well, Santa's elves are dealing with a little bit of a heat wave now at the North Pole," Sullins told viewers on Dec. 22, following an outline provided by Climate Matters. "It's 50 degrees above average up there." She showed an on-screen graphic with cartoons showing Santa Claus in increasing states of thermal distress.

At the bottom of the graphics appear a Climate Central logo and the source of the scientific data — in this case, temperature records and projections from NASA, the National Oceanic and Atmospheric Administration (NOAA), and a European atmospheric-science consortium.

The weekly packages distributed by Climate Matters also offer explanations from NASA or NOAA about the science behind each topic, as well as a summary of climate news and research. The effort is funded in part by a National Science Foundation grant that allows the organizers to measure progress.

When the project started up in 2010, Climate Matters tested its approach in Columbia, S.C. Viewers surveyed both before and after the yearlong pilot program showed a more scientific understanding of climate change than previously, and they had a deeper understanding of it than did viewers of newscasts on other stations.

Maibach, who is also an investigator for the federal grant that funds Climate Matters, periodically surveys broadcast meteorologists about climate change. The most recent survey, of 486 broadcast meteorologists, was released last month; it found that 95 percent agree that the climate is changing.

"I believe we are getting to some tipping point. We are reaching much deeper into the mainstream meteorologist community," says Bernadette Woods Placky, a former newscaster who is the chief meteorologist and program director at Climate Matters.

Still, only half of those surveyed managed to correctly identify human activity as the main driver of climate change. That's similar to the 53 percent of Americans who attribute it to humans, according to an "opinion map" by Yale Program on Climate Change Communication.

About a quarter of TV forecasters feared that if they spoke about climate change on air, "the feedback from management is or would be predominantly negative," according to the survey results, and 5 percent acknowledged that the election of President Donald Trump, who has been consistently dismissive of climate change, will cause them to speak less about it.

The politics aren't a factor for Sullins, even in a red state that voted for Trump by 4 percentage points. "For me, it's kind of flabbergasting why it's an issue," she said in an interview before the election. The management of her station backs her, which is not the case everywhere.

John Morales also has the support of his local station. He has been forecasting the weather in South Florida for 25 years and was an early adopter of Climate Matters. Miami, as he sees it, is experiencing the effects of the warmer future—sunny-day flooding, higher temperatures, and greater storm potential—faster than any other part of the continental U.S. Talking about the weather without talking about all that would be a strange omission.

A TV weather forecaster, Morales says, is a bit like a member of Congress when it comes to discussing climate change. A younger meteorologist in an area where climate change isn't widely accepted is more likely to stay quiet, regardless of any convictions, just like a rookie in Congress. Others "are very comfortable in their districts," Morales says, "and more likely to vote their conscience."

The hottest temperatures ever reported in Phoenix came in January 2015, when Fox 10 weatherman Cory McCloskey faced a malfunctioning temperature map on live television. "Wow, 750 degrees in Gila Bend right now," he said, without breaking a sweat. "And 1,270 in Ahwatukee. Now, I'm not authorized to evacuate, but this temperature seems pretty high." More than 6 million people have watched the blooper on YouTube.

Arizona is already hot, even when the TV weather map isn't on the fritz. Phoenix, Prescott, and Tucson are the second-, fifth-, and seventh-fastest-warming cities in the country; Phoenix and Tucson already rank as second- and 17th-hottest, respectively. The 90-degree benchmark that's usually reached in Phoenix around March 31 came this year on March 13, setting a record.

"Isn't it too soon for highs in the 90s?" Sullins asked in a segment last month. "The answer: Yeah, it is. On average, we don't usually hit the mid-90s till the middle of April. But not this year, and not in many of the years in our recent memory."

Sullins's introduction to climate science came just four years ago. Attending a September 2013 workshop for broadcasters at the University of Arizona, she took in a talk by Benjamin Santer, an atmospheric scientist at Lawrence Livermore National Laboratory and a prominent researcher linking human activity to warming. "I got to sit with him and ask him questions," she remembers. "It equipped me to better answer some of those questions that people ask me."

Sullins acknowledges she didn't know much about climate science back then. What she did know was that her job was changing. By 2013, there was no longer an expectation that a weatherwoman would appear just three times per night, delivering forecasts at 5 p.m., 6 p.m., and 11 p.m.

Instead she was appearing up to a dozen times per day in on-air and digital segments and responding to questions from her viewers. Trying to stand out from the noise, she found a need for climate science.

The materials from Climate Matters made it easier to communicate complicated ideas. "I love science, I love data, I love numbers, but not everybody else does," Sullins says. She knows half her audience may tune out at any mention of climate or global warming. "You just talk about how they're going to be affected as things change, and they're much more open to listening," she says.

Sullins's Facebook page offers as many images of Arizona's terrain and living environment as it does five-day forecasts. She sometimes drops in a climate-related factoid or news article, as she did on March 17, when she posted an article about a 1967 scientific study that "predicted global warming almost perfectly."

The post elicited a handful of responses, not all of them delighted. "We know this warming is due to human emissions of greenhouse gases because it's basic science," she responded to one skeptical comment. "If you add heat to something, it's going to warm up." She provided a link to scientific references.

Other commenters came to her defense. "Amen. Wish ‘the powers that be' would listen to the science too," one wrote. There was no reply from the meteorologist — Sullins has learned to avoid digital shouting matches — but a careful onlooker might notice a blue thumbs-up button underneath the supportive comment. Hover a cursor over the button and a familiar, authoritative sentence pops up: "Amber Sullins likes this."