Climate change threatens far more than our environment. It’s already led to the spread of infectious diseases and respiratory ailments across the globe and contributed to thousands of deaths through heat waves and other extreme weather events. It’s even fueled recent revolts in the Middle East and North Africa.

That’s according to Dan Ferber and Dr. Paul Epstein, the authors of a new book, Changing Planet, Changing Health: How the Climate Crisis Threatens Our Health and What We Can Do about It (University of California Press, April 2011).

The health of all humans is directly tied to how we, as communities, nations, and a global population, respond to the growing climate threat, says Ferber, a science journalist and Epstein, Associate Director of the Center for Health and the Global Environment at Harvard Medical School.

Ferber and Epstein spoke with Reuters Health Thursday about how malaria, Lyme disease, and cholera, as well as cooking shortages and malnutrition, are all becoming increased risks with steadily rising temperatures. (See the live blog from the discussion here: http://bit.ly/lJnshE)

While getting out of the corner humanity has backed itself into will take a worldwide effort, they say that effort may be led by a surprising player: industry.

"Changing finance is a critical part of … rewriting the rules" on climate management, Epstein said.

For the financial industry, there’s a lot at stake, Epstein continued.

"With the uptake in extreme events — particularly as it’s affecting food security globally and food prices — we’re going to see a renewed interest on the part of the investors and insurers in the stability of society," he said. Already, "the financial industry has at times in the last several decades been acutely aware of the dangers and risks of climate change."

Many threats, one cause

Climate change is hitting human health — and political and social stability — from all sides, Epstein and Ferber said. On a daily basis many of those impacts are hidden from view — until you take a step back.

Even slight increases in temperature — a couple of degrees — can broaden the habitat of pests that cause infectious diseases, from malaria in Kenya to Lyme disease in Maine, they said.

And the claim that regions saturated with infectious disease will just shift, rather than expand, isn’t helpful because it misses other key points, Epstein said.

For example, in parts of Honduras it’s gotten too hot for malaria-carrying mosquitoes to thrive. "But it’s been so dry and hot that the people have moved as well, and they’ve moved into the northern area, into the forest, where there’s plenty of malaria," he explained.

Pests also target wildlife, wiping out forests and increasing the risk of fires, such as in the Rockies and Cascades, where it used to be too cool for those pests to venture to high altitudes.

Another result of a changing climate: heat and carbon dioxide magnify the effects of asthma and allergies, particularly in cities where more and more children are developing respiratory problems.

And a combination of heat waves — such as the one that killed thousands of Russians last summer — and droughts not only causes immediate local health crises but also threatens global public health by destroying crops and driving up food prices, the authors said.

Food availability may be the most pressing issue of all.

"Our food, our air, our water, these are the issues that really underlie our public health," Epstein said. "These are the life support systems. These are the ones that ultimately are most critical and most sensitive to climate instability."

An unstable climate, Epstein explained, is directly linked to social and political unrest. "I think we’re looking at increasing damages and social disruption from the climate instability and extremes," he said. "The earth itself can go to a new equilibrium, but we need to back off. We’re pushing it hard."

A chance for industry

But it’s not all bad news, and Ferber pointed out there is reason to be hopeful that we might be at a turning point in terms of accepting and addressing climate change — a shift that could be driven by economics.

Some companies, he explained, have already figured out ways to profit and grow by switching to climate-friendly policies.

For example, Ferber said, the re-insurance company Swiss Re realized that it could insure wind farms at a lower premium than oil rigs, because entire wind farms aren’t likely to be felled in a disaster.

"That benefited the company, and it also benefited the wind farm developers," Ferber said. "This kind of creative thinking in the financial world can lead to win-win solutions."

He gave Stonyfield Farm as an example of another company that has figured out how to turn environmental protection into a business strategy, such as by using microbes to ferment some of its dairy waste — erasing the costs of shipping it away to be treated elsewhere. Stonyfield’s yogurt revenue now tops Kraft’s, the authors said.

A new direction

As industry players start to realize that coal-fired power plants, for example, might not be a good investment, Ferber said, communities can also take steps to make their streets, businesses, and homes more climate-healthy. Planting trees, installing bike lanes and green roofs, and funding projects to help residents green their homes are all feasible steps that together could make a concrete difference, he suggested.

And the evidence shows that we’re running out of time to start taking these steps.

Epstein said that humans need to dramatically decrease fossil fuel and wood burning "in order to give the climate a chance to re-stabilize at a level that would be viable" for environmental and human health.

"People across this country are realizing that we have a real problem on our hands," Ferber said. "I am actually optimistic that more and more people are starting to deal with that reality and say, ’what solutions can we come up with to deal with this problem?’"