The science around climate change is clear, which leads many to wonder why the will to limit global warming has lagged behind.

“The no. 1 thing that we are missing is a sense of efficacy,” Katharine Hayhoe, chief scientist at the Nature Conservancy, said at Yahoo Finance's All Markets Summit (video above). “We don't think that anything we do will make a difference. But the world has changed before. And when it changed, it was when individual people use their voices to talk about how the world could be different.”

The challenge is not in convincing people that climate change is real, she explained. It's spurring action among enough people to change the status quo.

That notion is in line with polling data on Americans' attitudes on climate change. According to the Yale Program on Climate Change Communication, 72% of U.S. adults acknowledge that global warming is happening, but only 35% of adults discuss global warming at least occasionally.

“We have known since the 1800s that digging up coal, back then, and oil and gas, today, are producing heat-trapping gases that are wrapping an extra blanket around the planet, causing it to warm,” Hayhoe said. “What are we missing? We don't understand how it affects us, why it matters to us here and now today in ways that are relevant to each one of us. And we don't know what to do about it."

Climate change's effect on communities

One of the ways climate change is affecting communities is through extreme heat, according to Christian Braneon, a climate scientist at NASA's Goddard Institute for Space Studies.

By mid-century, 1.5 billion people living in urban areas worldwide will be exposed to extreme heat, Braneon said. He stressed that the urban poor, in particular, will be disproportionately affected.

“A lot of people don't realize that the deadliest weather hazard in the United States is actually extreme heat,” Braneon told Yahoo Finance. “Heat waves are becoming more intense. Heat waves are lasting longer. Heat waves are causing folks to be hospitalized and causing folks to have a lower quality of life.”

'Heat islands' within cities also inordinately impact communities of color. Researchers have found that historically redlined neighborhoods are 5 degrees hotter on average than those that were not, according to the New York Times.

“I think if we focus more on the folks that are actually the victims from climate change — and we have a lot of confidence from global climate models in terms of what's going to happen in terms of heat and heat waves — we can kind of get folks' attention, because we all kind of have a connection to extreme heat,” Braneon said.

How to use your 'climate shadow' to effect change

Hayhoe offered some insight into how individuals can act to actually make meaningful change.

“Every one of us, we don't only have a carbon footprint as people often talk about," Hayhoe said. "We also have a climate shadow. And our shadow is much bigger than our footprint."

“What is our shadow?" she continued. "It is our sphere of influence. Every one of us works somewhere. We live somewhere. We engage with community organizations, or places of worship, or school kids groups, or sports teams. All of us engage with people beyond our own personal boundaries.”

That influence can be used to advocate for change, Hayhoe explained. She also recommended that individuals “look for examples of how that change has already happened."

One place to start is to simply talk about the issue, Hayhoe said. By talking to neighbors, coworkers, and others in your climate shadow, individuals can gradually shift social norms towards sustainability.

“It's showing people there's a different way to do things and be than there used to be,” Hayhoe said, pointing to areas where social norms are already beginning to change, such as with the broader acceptance of electric cars, sustainable agriculture, and renewable energy.

“But those are still in the pioneer phase, and they need to move more quickly — not just at the individual level, but the level of our entire system,” she said.

Hayhoe also said contacting elected officials is another way to use your climate shadow to leverage stronger climate action, as “politicians respond to the will of the people, ultimately.”

For people to “realize and mobilize and use their voice to advocate for action, to say, 'This matters to every single one of us, no matter where we live, it's affecting us here today,' that's what we need to get: the will to fix this thing,” Hayhoe said.

Grace is an assistant editor for Yahoo Finance.

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