One of America’s largest health care companies is warning that climate change will worsen public health problems and make it more difficult to provide services.

Kaiser Permanente is the biggest non-profit health care company in the U.S., serving more than 9 million people with an operating revenue of $44 billion. Speaking to Andrew Winston of the Harvard Business Review, a Kaiser spokeswoman explained why the health care giant is concerned about a warming planet:

I spoke recently with Kathy Gerwig, KP’s Environmental Stewardship Officer, to find out. I expected a more typical answer about achieving GHG reduction goals or doing the right thing. What I got instead was one of the most straightforward statements about the role of climate change in public health and in corporate strategy.

As Gerwig put it, “there’s credible evidence of significant climate change that will impact our ability to provide quality health care.”

…”What we know so far about the repercussions of climate change isn’t good,” Gerwig says, “such as water shortages and increased wars over resources, and all the health issues that go along with those.”

In February of this year, Kaiser announced it would reduce greenhouse gases 30 percent by 2020 compared to 2008 levels. The company says that the health care industry accounts for 8 percent of America’s greenhouse gas emissions.

As Kaiser’s spokeswoman points out, these greenhouse gas targets aren’t just for public relations — they stem from a corporate recognition that extreme weather will threaten more people directly, while also exacerbating spread of diseases due to flooding, water shortages, and warming temperatures.

These threats are already evolving. Warming temperatures are helping to spread dengue fever in 28 U.S. states; flooding in Australia has increased outbreaks of the deadly Hendra virus in humans; and a changing climate could also influence genetic changes in bacteria like E.Coli, making them more deadly.

In 2009, the University College London Institute for Global Health issued a report concluding that climate change “will have devastating consequences for human health.” The report also warned that the potential global health impacts are “not being grasped by the healthcare community or policymakers.”