Natural disasters are a fact of life.

There's no controlling Mother Nature, and her wrath can, at times, be staggering. Last year, natural disasters—from droughts in Africa and Russia to typhoons and massive flooding in Thailand—caused a record $378 billion worth of damage.

The indications are that the situation will get worse, not better. Climate change is likely to make weather patterns more extreme. There's no ignoring the problem, but there remains a critical question: What protects us better, human engineering or natural landscapes? There's a natural human urge to rely on the things we make, but the lessons of the past decade have led in a different direction.

Often, the great works of civil engineering that we built as insurance against disaster had the opposite effect. Hurricane Katrina is a great example. Over the past century, the levees built to protect low-lying New Orleans choked off the natural wetlands that once served as a buffer between the Big Easy and the Gulf of Mexico. Erosion has wiped out 1,900 square miles of wetlands since the 1930s.

Natural Defenses

Researchers estimate that every 2.7 square miles of wetlands reduces storm surge by a foot. So when the hurricane hit—with the area's natural buffers mostly gone—the resulting flooding overwhelmed the city's elaborate man-made defenses, leading to the worst natural disaster to hit the U.S. in decades.

In Katrina's case, environmental degradation played a direct role in turning a bad storm into a total catastrophe. But in other places, it's the sheer complexity of the human-built environment that makes it more prone to catastrophic failure. Take last year's tsunami on the northern coast of Japan. It was bad enough by itself, but it was made worse when it set off a chain reaction that caused a meltdown at the Fukushima nuclear power plant.

That's why the upcoming United Nations Conference on Sustainable Development (Rio+20) will take a look at disaster preparedness from a different angle. Is it possible to use "green" methods to avert catastrophe?

"The natural infrastructure provided by ecosystems is often more locally accessible and less expensive to maintain than human-made, or 'gray' infrastructure," UN Environmental Program (UNEP) Director Ibrahim Thiaw said recently. "Healthy ecosystems are the best 'insurance cover' for those who depend on natural resources for their livelihoods and ultimately provide multiple social, economic, and environmental benefits regardless of whether a disaster occurs or not."

Blueprint for Action

Combining disaster preparedness with sustainable development may be a hard sell, but successful efforts are already under way. Even the Netherlands—one of the most engineered countries in the world—has instituted a program to make "Room for the River," re-establishing the floodplains of its rivers.