On a Wednesday afternoon in late November, Josh Rosen ambles through large red double doors and into the television studio at the Dignity Health Arizona Cardinals Training Center in Tempe.

The rookie quarterback is here to record a video on climate change for "My Cause, My Cleats," the league-led initiative that allows players to promote awareness for issues important to them by wearing custom footwear during a game.

Rosen chats breezily with the assembled staff while waiting his turn, and then heads into a soundproof room to tape his piece. The video takes but a few minutes and will be part of a larger product that highlights the causes of multiple players on the team.

As Rosen heads to leave, he is stopped short. At 21, he is barely old enough to buy alcohol, but has a keen sense of the world around him. He could have supported many different causes. So why choose climate change?

Rosen clears items from a concrete bench and invites a reporter to sit down. His tone grows serious.

"Objectively," he says, "it is the most important. We're getting close to a certain point where there is no turning back."

While the decibel level never changes when Rosen speaks, there is an edge to his words. Only a few weeks prior, wildfires ravaged his home state of California, killing dozens and displacing thousands. (He opened his first press conference after the tragedy pleading for donations to the Red Cross, and later wore a Los Angeles Fire Department shirt in pregame warmups against the Chargers.)

While help is critical after catastrophes strike, Rosen wants to focus on preventative measures, and "My Cause, My Cleats" is the perfect vehicle. He will wear blue and teal cleats on Sunday against the Lions to promote Parley, an environmental organization aiming to thwart destruction of the oceans.

The overarching goal, Rosen says, is a substantial uptick in environmental care to avoid the ramifications of inaction. Rosen points to a study by the UN Intergovernmental Panel on Climate Change in early October that detailed the potential impact if the earth warms by 1.5 degrees Celsius.

"Something crazy like 75 to 80 percent of the world's population lives in coastal areas, so there's going to be massive, massive mass migrations," Rosen said. "You think the refugee crisis is bad now? It's only going to get worse. Famines are going to get worse. Island countries off the coast of Africa, they are literally going to disappear.

"The earth will be fine. It's just whether the earth will be fine and have humans on it."

Rosen details the issues already afoot: the longer migration patterns of animals due to scarcer resources; the seasonal flooding in Venice, Italy so pronounced that the first stop for tourists has nothing to do with sightseeing.

"They literally sell rain boots in the big quad," Rosen said. "And they don't have anything on the floor any more of their shops, because it's constantly getting flooded."

Rosen can be stubborn, but present him with persuasive evidence and he is willing to change his mind. On the topic of climate change, he refuses to budge.

"It's not a question," Rosen said. "It's not even close to a question. (Some will say) 'OK, there's enough information, do what you want with it.' But at some point you've got to be like, 'Alright, we've got to do something.' I definitely intend on trying to get involved with different projects, different organizations that do certain things, try to help pass some legislation. Obviously I can only do so much, but I'm trying to hopefully inspire some other people who are a little more powerful and important than me to continue to do their part, and affect even more people."

Cardinals offensive coordinator Byron Leftwich likes to say Rosen is a 21-year-old going on 36. In truth, that might be selling the rookie short, as few people in their 30s have a worldview as complex.

"You'd be amazed at some of the conversations we have," Leftwich said.

Rosen comes from a well-to-do family in which education was a high priority. His great-great-grandfather, J.B. Lipincott, owned a publishing company and spawned a lineage of voracious readers. Rosen learned early in life that when challenging a premise, he needed to be factually equipped.

"Whenever we would go back east for Christmas, our dinner table conversations were pretty combative," Rosen said. "You had to know your stuff or else you'd get toasted."

Green Bay Packers quarterback Aaron Rodgers met Rosen for the first time earlier this year. It was a made-for-TV introduction set up by their sports agency, Athletes First, but an authentic friendship bloomed.

"He's a really curious guy," Rodgers said. "He's interested in a lot of different things and always learning and reading and studying up on stuff. He knows a lot about a lot. I definitely related to that."

Rosen is far from the only informed player in the NFL, but many avoid deeper debates for fear of ruffling feathers. That's not the case in the Cardinals' quarterback room, which has started to double as a miniature "Crossfire" set.

"I've probably talked more about current events and politics this year than in all my years in the NFL combined," said 28-year-old backup quarterback Mike Glennon, a six-year veteran. "And Josh is 21 years old. That's a conversation most 40-, 50-, 60-year-olds are having, not 21-year-olds. He's opened my eyes to some things."

While only a rookie, Rosen is already beginning his civic push. In September, Cardinals veterans Tre Boston, Antoine Bethea and Corey Peters met with Arizona Governor Doug Ducey to discuss criminal justice reform.

All three are black, and the issue is near to their hearts because incarceration rates disproportionately affect low-income minorities. Boston was pleasantly surprised when Rosen, a native of affluent Manhattan Beach, California, tracked him down afterward and pledged his support.

Boston knows Rosen can be a pivotal ally in bringing attention to the topic.

"A quarterback in this league," Boston said. "A white quarterback at that. ... He's been trying to be involved in that stuff, and we thank him. We know how much we need that piece of the puzzle to help us out."

For someone as famous as Rosen, the willingness to take a stand can be divisive. It's why so many NFL players prefer diplomacy over honesty, as drab answers don't make national waves. Rosen has dealt with serious blowback for his lack of political correctness, and yet, he doesn't change.

"I've never held myself back at any point," Rosen said. "If y'all ask me about it in an interview, I'm going to answer."

Rodgers -- known for speaking the truth himself -- appreciates Rosen's candor when the easy way out is to spout clichés.

"Oh, hell yeah," Rodgers said. "I respect it. He's going to let you know what he's thinking and live with the consequences. I think there's a lot to be said for that honesty. Also, he knows what he's talking about. He's a thoughtful guy. He's not just popping off at the collar. He's thought about the things that he wants to say and stands behind his words."

Rodgers' point proves prescient when the conversation with Rosen weaves into politics -- an untouchable topic for many of his stature, but one Rosen brings up himself. The midterm election results are still fresh and he is excited about the newfound diversity that has landed in Congress.

"We had NFL players win," Rosen said. "We had the first gay person, the first Muslim."

Rosen is encouraged by the increased political aptitude of twentysomethings like himself, an age group notorious for its apathy.

"I think a lot of kids are more aware, especially with social media, than they've ever been," Rosen said. "You saw these school shootings, and the (expletive) students are starting to fight back now. I think it's a general societal thing. In the past, social structures and leadership used to be very defined and clear-cut. Nowadays, people are starting to realize that a good idea is a good idea, regardless of where it comes from."

The discussion eventually circles back to climate change. Rosen does what he can to help the environment – he drives an electric car and wears cleats made from plastic fished from the ocean, among other things -- but knows it will take a global effort for drastic change to result.

Rosen believes the evidence of impending danger is overwhelming, and "it's literally just people swallowing their pride" and enacting change.

It's no secret that Rosen's words have a partisan element to them, and by being outspoken, he risks alienating some fans. Despite this, Rosen is unwavering. The yearning for a better tomorrow supersedes concerns about his own popularity.

"I know I might rub a couple people the wrong way, but like, you're wrong," Rosen said. "If you want to talk about anything, I want to form my opinion, but this one, it's just not a debate. If people yell at me, I'll take it. I'm trying to give my kids a safe place to live."