This may surprise you.

King County Metro is buying a fuel that is significantly more expensive than diesel, may be worse for the environment, may increase local food prices, may lead to global hunger and potentially cost King County more as a member of the Chicago Climate Exchange.

That fuel is canola-based biodiesel.

Not so long ago, biofuels were all the rage. The promise of a clean-burning, non-fossil fuel was compelling.

In 2006, the King County executive initiated an executive order that would require King County Metro’s bus fleet to start using a 20 percent blend of biofuel. This requirement was included as a demonstration project in the 2007 Climate Action Plan.

But today, the scientific evidence against certain biofuels is mounting.

Numerous stories in peer-reviewed journals are reporting that biofuels may be leading to rising worldwide food prices. Indeed, the International Monetary Fund, World Bank and the United Nations have claimed that the use of food as a fuel has increased primary demand for corn, sugarcane and palm oil — and secondary demand as people switch to wheat and rice in their diets.

Worse, research from leading universities and institutions has shown that certain kinds of biofuels may actually increase greenhouse gas emissions.

When land is cleared for biofuel crops, trapped carbon is released into the atmosphere. When land is chemically fertilized, the soil microbe interactions produce nitrous oxide (N2O) — a potent greenhouse gas that is 296 times more damaging to the environment than carbon dioxide.

But biofuels are also having an impact right here in King County. The average cost of a gallon of canola biodiesel is $1.50 more expensive than standard diesel. Even with a federal subsidy of about $1 per gallon, we are still paying 50 cents more per gallon of biodiesel — and we purchase about 2 million gallons per year, which means about a million dollars annually may be going into fuel that isn’t providing the desired benefit.

As the chairman of the Regional Transit Committee, I recently called for a full life-cycle analysis of the biofuel from land-clearing, planting, harvesting, transporting, biodiesel conversion, production and usage. We must understand all of the impacts — not rush into something that makes us feel more green.

King County Metro now has the opportunity to re-examine all of the alternatives including diesel, plug-in electric, solar, renewable natural gas and non-food based biofuels. But this time, we must also consider the cost to King County taxpayers, economic impacts on food (locally and abroad) and the whole life-cycle impact on the environment.

Global warming is a serious issue that needs to be addressed. However, we can’t afford to make bad decisions that don’t actually deliver a cleaner environment. The motion I have put forward will make sure that our decisions are accountable for the environment and to taxpayers.

Reagan Dunn of Maple Valley represents the Ninth District on the King County Council.