The presidential candidates at the CNN climate forum on Wednesday repeatedly emphasized how climate change is hurting low-income communities and people of color, reflecting a growing awareness among Democrats that many of the problems they seek to address are inextricably tied to racism, poverty and other forms of discrimination and inequality.

Nine of the 10 participating candidates — all except former Vice President Joseph R. Biden Jr. — named or clearly alluded to environmental justice, a framework that calls for environmental policies to explicitly address racial and economic disparities exacerbated by a warming planet.

It was an acknowledgment, as several candidates put it, that decades of racist and classist policies have concentrated people of color and poor people in the most polluted communities, and that those most immediately and severely affected by climate change are often those with the fewest resources to respond.

The environmental justice movement “embraces the principle that all communities and all people have a right to equal protection of our environmental laws,” said Robert Bullard , a professor of urban planning and environmental policy at Texas Southern University who pioneered the movement. “It’s equal access to the good things that make communities healthy, but also making sure that no community is overburdened because of their income or because of their race or their geographic location.”