Climate change is disproportionately affecting the poor and minorities in the United States - a "climate gap" that will grow in coming decades unless policymakers intervene, according to a University of California study.

Everyone, the researchers say, is already starting to feel the effects of a warming planet, via heat waves, increased air pollution, drought, or more intense storms. But the impacts - on health, economics, and overall quality of life - are far more acute on society's disadvantaged, the researchers found.

"Climate change does not affect everyone equally in the United States," said Rachel Morello-Frosch, associate professor at the School of Public Health at the University of California, Berkeley and lead author of The Climate Gap. "People of color and the poor will be hurt the most - unless elected officials and other policymakers intervene."

Watching this unfold is akin to watching a movie where disparate and seemingly unrelated storylines converge to denouement that is "decidedly tragic," the researchers wrote.

For instance, the report finds that African Americans living in Los Angeles are almost twice as likely to die as other Los Angelenos during a heat wave. Segregated in the inner city, they're more susceptible to the "heat island" effect, where temperatures are magnified by concrete and asphalt. Yet they're less likely to have access to air conditioning or cars.

Similarly, Latinos make up 77 percent of California's agricultural workforce and will likely see economic hardship as climate change reworks the state's highest-value farm products. The dairy industry brings in $3.8 billion of California's $30 billion agriculture income; grapes account for $3.2 billion. Yet climatic troubles are expected to decrease dairy production between 7 percent and 22 percent by century's end, while grapes will have trouble ripening, substantially reducing their value.

Other impacts, according to the researchers: Households in the lowest income bracket spend twice the proportion of their income on electricity than those in the highest income bracket. Any policy that increases the cost of energy will hurt the poor the most.

California industries considered heavy emitters of greenhouse gases have a workforce that is 60 percent minority. Any climate plan that fails to transition those workers to new "green energy" jobs threatens to widen the racial economic divide.

Minorities and the poor already breathe dirtier air than other Americans and are more likely to lack health insurance. As higher temperatures hasten the chemical interactions that produce smog, they're going to feel the most impact.

The findings, the researchers say, underscore the need for policymakers to consider environmental justice when addressing climate. Ignoring the climate gap, they warn, could reinforce and amplify current and future socioeconomic and racial disparities.

"As America takes steps to prevent climate change, closing the climate gap must also be a top priority," said Manuel Pastor, a co-author and director of the Program for Environmental and Regional Equity at the University of Southern California's Center for Sustainable Cities. "If we protect those who are most vulnerable, we will protect all of us."

Current debate on Capitol Hill and in many statehouses favors programs that cap emissions and lower the cap over time, using permits to ensure compliance. But many of those programs propose to allocate all or some permits for free, depriving public coffers of revenue to help families living in poverty absorb the higher costs for food, water and electricity.

The researchers also found most emissions trading and fee programs are blind to the location of the source: It makes no difference to climate change to reduce greenhouse gas emissions in a dense urban neighborhood or an unpopulated rural area. But it can make a huge difference in public health, they noted, particularly as many urban greenhouse gas emitters also pollute the air and are  located in poor neighborhoods.

"By choosing policies that shield against the very real dangers facing low-income neighborhoods and people of color," Pastor said, "we will insure that climate policy will be effective for all of us."

This article originally appeared at The Daily Climate, the climate change news source published by Environmental Health Sciences, a nonprofit media company.