The climate crisis lingers in the back of Gemma Gutierrez’s mind, a gnawing anxiety that blossoms fully when she reads about wildfires, flooding or other climate-related disasters. It’s a nagging concern that clouds how the 16-year-old sees her future.

“I have a sense of dread,” says Gutierrez, who lives with her parents in Milwaukee. “I dread that in my lifetime the clean water I have now or the parks I’m lucky enough to be able to go to won’t be there any more. It weighs on my mind.”

Like a growing number of young people in the US, Gutierrez sees climate change casting a long shadow over her adult years. She has been inspired by Greta Thunberg, the teenage climate activist, and has contacted her local elected representatives to raise her concerns.

The looming US presidential election has only sharpened her fears, as well as underlining a generational rift in her family. In a scenario playing out in many American families, a sense of despair and outrage among young people over global heating is being met with indifference and even dismissal among some of their older relatives.

While polling shows a clear majority of Americans accept that the climate is changing and want the federal government to respond to the myriad threats this poses, the issue has been polarized in the US to extremes not seen in other leading democracies.

An ideological aversion among Republicans to accept climate science and act against fossil fuel interests has led to two starkly different visions laid out by the 2020 presidential candidates. While Trump has rolled back dozens of pollution regulations, dismissed and sidelined climate science and pulled the US from the Paris climate accords, Joe Biden is pushing a $2tn plan to create a 100% clean energy grid within 15 years, and has called the climate crisis “an existential threat” to the US.

But a generational divide is also opening up, with younger people – even young conservatives – increasingly alarmed over the impact of global heating. An overwhelming 80% of voters aged between 18 and 29 consider the climate crisis “a major threat to life on Earth”, according to a poll taken earlier this year. Levels of concern among older people, particularly Republican voters, lag significantly.