At age 6, climate change activist Xiuhtezcatl Martinez gave his first speech to a packed crowd in his hometown of Boulder, Colorado. Raised in the Aztec tradition, he was taught that as indigenous people, they are descendants of the land and inherit a duty to protect it.

“I felt such sadness that my generation inherited this crisis to clean up. That night, I saw that those emotions could be channeled into action and my voice could make a difference,” says Martinez, founder and youth director of the nonprofit Earth Guardians.

Ten years later, his impassioned message has sparked a global movement. More than 2,000 “youth crews” from Bhutan to Brazil are fighting climate change and improving their communities in other ways.

These activists aren’t yet old enough to vote, but are still making their voices heard by global policymakers. On their behalf, Martinez delivered a plea to representatives from 192 countries at the United Nations General Assembly meeting on climate change last year, asking for stronger measures to protect both the planet and its people. He particularly pointed to the ever-increasing “climate refugees” that have lost their homes to rising oceans and other havoc caused by Earth’s warming trend.

Although Martinez serves on President Obama’s youth council, he and 20 other young plaintiffs filed a landmark lawsuit earlier this year against the federal government for failing to protect its citizens from climate change. The plaintiffs are seeking a court order requiring America’s president to establish a national plan to decrease atmospheric concentrations of carbon dioxide to “safe” levels by 2100.

At home, Martinez is working with Boulder County community and environmental organizations to locally eliminate pesticides from parks, charge for plastic bags at retail, regulate coal ash emissions and ban fracking.

EarthGuardians.org offers many ways anyone can plug into the movement, whether taking individual actions to lighten our carbon footprint, creating school gardens or signing its Silence into Action pledge, inspired by Martinez’s younger brother Itzcuauhtli’s 45-day silence strike for climate action.

“The most important thing you can do is educate yourself. Whatever makes you come alive, use that passion to make a difference,” says Martinez, whose performances as a pianist and hip-hop artist inform and enliven music festivals worldwide. “Together, we can create a legacy we can be proud to pass on to the next generation.”

Connect with freelance writer April Thompson, of Washington, D.C., at AprilWrites.com.