Scientists, executives, journalists, politicians and environmental groups focus attention on climate change challenges and calls for action. Those adults aren't the only age group raising awareness of shrinking glaciers, rising sea levels, lower crop yields, affected wildlife and other impacts from the globe's gradually rising average temperatures. High school students, who'll live on this warming planet longer than most grown-ups, also make themselves seen and heard. "Climate mobilization" events took place in Seattle, Fort Lauderdale, Fla., Washington, D.C., and other cities this month, organized by about two dozen students. There were rallies, marches and speeches.

In the national capital, three days of activities included a Youth Climate Art Festival and meetings with about 40 members of Congress or their aides. A key message of the Capitol Hill lobbying was a request to refuse political contributions from coal and oil companies. "They're basically paying off public officials with campaign funds to not pass climate change legislation," says 18-year-old Maeve Secor, who came from of Baltimore.

Zero Hour, a year-old environmental justice group behind the events on and around July 21, was created by four teens. It hopes to harness the momentum of other recent youth-led movements, such as March for Our Lives rallies against gun violence. "This is going to affect us. Our futures, our careers, our lives," says Talia Grace. Zero Hour's main founder, 16-year-old Jamie Margolin of Seattle (see video below), says: "I just want to have a world to grow up in where I can live my life and not have to worry about such existential fears."

The young activists, who work with adult advisers at their offices, want to eliminate fossil fuel subsidies and end federal support for oil refineries, pipelines and coal mines. Instead, they want to see the government invest significantly in local solar and wind energy companies. It's "a movement of unstoppable youth . . . [who want] to ensure a livable future," says their website (thisiszerohour.org). They're endorsed by the Sierra Club, Citizens Climate Lobby and other older groups.

Founder says: "It's zero hour to act on climate change. Let's take advantage of this window of time we have left. Let's change everything, because the world literally depends on it." – Jamie Margolin, 16, of Seattle

Foreign student says: "There is no more time. We do this now or we're done." -- Kibiriti Majuto, 20, of the Congo (in Africa), working with the U.S. group

Teen "lobbyist" says: "I'm here because I know this an urgent problem we need to solve and we need to address. I'm really worried about the water levels rising; that's really going to affect Baltimore, especially with the impact climate change has on the low-income population." – Maeve Secor, 18, Baltimore