Earth's delicate climate balance is affected by greenhouse gases released into the atmosphere. Credit: NASA

Myth #4: A hydrogen-based economy could have an unforeseen impact on the Earth's climate.

There may be rancorous political debate about global warming, but little scientific debate remains. The planet's overall temperature rose about 1 degree Fahrenheit during the last century. The phenomenon is well known as the greenhouse effect and it is the direct result of burning fossil fuels. One degree may not sound like a lot, but researchers have already documented significant impacts on agriculture, wildlife, diseases and weather patterns. And as long as we keep releasing greenhouse gases into the atmosphere, the warming trend will continue.

One reason transitioning to hydrogen fuel is so attractive is that pure water is its only waste product. What could be more harmless than pure water? As it turns out, water vapor is known to have an impact on regional temperatures. As Scientific American Frontiers has previously reported, "As soon as officials recognized that terrorists had hijacked at least four planes on the morning of September 11, 2001, all commercial air traffic was grounded in the U.S. for three days. The situation provided atmospheric scientists with the unique opportunity to study how the exhaust from all those airplanes affects the weather."

Airplane contrails are made of water vapor -- and can affect local temperatures.

By looking at the average daily temperature range for September 11- 13, 2001, and comparing that to the average daily temperature range for the same days in September over the last 30 years, climatologists found that the temperature range was about 2 degrees Fahrenheit greater while the planes were grounded. The scientists hypothesized that the jet exhaust — or contrails — act like artificial clouds, simultaneously blocking incoming solar energy and trapping the heat radiating off the planet's surface. In this way, jet contrails keep the Earth cooler during the day and warmer during the nights. Although the jet contrails' effect was regional and not global, this study shows how small changes can make measurable differences in the atmosphere.

	Clouds of water vapor help determine the amount of solar radiation reaching earth. How would wide use of hydrogen fuel affect this system? Credit: Warren Gretz

Because of the complexity involved in climate modeling, no one can say exactly how transitioning to hydrogen would affect the planet. While that topic certainly merits further study, we do know that our continued dependence on carbon-emitting fuels will continue the warming trend so thoroughly documented over the last century.

"A poorly designed hydrogen transition could cause environmental problems," Lovins concedes in "Twenty Hydrogen Myths." "But a well-designed one can resolve most of the environmental problems...without making new ones."

In his State of the Union address in 2003, President George Bush — not exactly a darling of the environmental lobby — announced his Hydrogen Fuel Initiative, funding that could ensure that "the first car driven by a child born today could be powered by hydrogen, and pollution-free."

President Bush talks on a fuel cell-powered cell phone. Credit: Paul Morse

In 2004, the Department of Energy awarded $75 million in research grants for hydrogen research projects. Yet Lovins says some of the myths he works to dispel are still propagated on the DOE's own Web site. Lovins maintains that economics above all else makes the transition to the hydrogen economy an inevitability. The sooner these myths are dispelled, the sooner we can all realize our hydrogen hopes.

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