We should welcome Sierra Club Hawaii’s call for serious planning in relation to the state’s food system ("Robert Harris: The leader of Sierra Club Hawaii … " Star-Advertiser, Oct. 22). However, like some others, Sierra Club Hawaii equates food security with food self-sufficiency. It is not clear whether, and how, increasing food self-sufficiency would achieve increased food security.

According to the Food and Agriculture Organization of the United Nations, "Food security exists when all people, at all times, have access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life."

If Hawaii produced all its own food, it would face risks of failure of local crops, just as other Pacific islands faced the taro blight a few years ago. Real food security would come from diversifying our food sources, so that we could jump to alternative sources as needed. Overdoing the push for self-sufficiency would mean exchanging one set of vulnerabilities for another.

How should food self-sufficiency be measured? There is no doubt that a huge proportion of Hawaii’s food is imported, but so far there has been no good way to actually calculate that proportion. The data required are not available to the public.

If we decide to pursue, say, 50 percent self-sufficiency, does that mean the amount of food produced on Hawaii’s farms should be roughly equal to the amount of fresh food imported from outside Hawaii? Should they be of equal weight, or equal value, or what?

Fresh food is produced on farms, but the finished products have "value added" in factories, restaurants and markets. Only a small fraction of the total cash value of our food goes to pay farmers. Are we saying half the retail value of all our food products, fresh and processed, should go to local producers and processors’ foods?

Many foods now available in our markets cannot be produced locally at reasonable costs. Increasing food self-sufficiency probably would reduce the variety of foods available to us.

We import because we can obtain many foods from elsewhere at lower cost. With Hawaii’s high land and labor costs, we cannot assume that increasing self-sufficiency would result in lower food prices. Higher food prices would be especially harmful to people with low incomes.

It makes sense to go for some reduction in Hawaii’s food imports, but we haven’t yet figured out what would be the optimal level. Benefits and costs, including risks, need to be estimated in a systematic way. Attention should be given to the likely impacts on different groups of people. Health, protection of the environment, and preparation for contingencies of different kinds should be among the many considerations taken into account.

Rather than focus on self-sufficiency, the core objective for Hawaii’s food system should be achieving good nutrition for all under all conditions.