I'm a GMO skeptic.

I'm one of those people who believes the science of climate change, but not the science of GMO (genetically modified organism) food safety. According to the Pew Research Center and D.J. Tice ("It's empirical, Americans just don't trust science," Dec. 11), I should trust both.

I'm not a scientist. I don't have enough knowledge of food science or climate science to be able to analyze the claims in each field. So I have to use a form of shorthand to decide whether a scientific claim is likely to be true. Here's how the two stack up.

Is the science consistent? Climate science hasn't changed substantially in more than 50 years. Each new finding and study builds on previous findings. If anything, the biggest difference is that climate scientists underestimated the rate of change because they didn't account for the rapid growth of Chinese manufacturing and the climate changing gases that would come from that country.

The food and agriculture industries have a far less stellar record. The only thing consistent in food safety claims is the running joke that if you don't like the current status of your favorite food, hang on, it will change next week. Recent examples include milk, good for strong bones or a likely cause of early death; calcium supplements, essential to avoiding osteoporosis or stop taking it altogether. Eggs, a sure cause of high cholesterol or not a problem.

We've had the same problem with the safety of agricultural practices. In 1962, Rachel Carson published "Silent Spring" about the dangers of DDT. Since then a long list of pesticides has been declared safe, then unsafe. A very small sampling includes: aldicarb, a farm chemical that caused the worst known outbreak of pesticide poisoning in North America; neonicotinoids, hailed as absolutely safe for humans then suspect of being a prime source of bee die-offs; Roundup, the most widely used herbicide in the world now known to be deadly to human cells.

Is there a bias to the science? When climate scientists first raised the alarm, there was no constituency for their findings. The solar and wind industries were too small to fund additional research, and there was no profit in getting citizens to drive less. Grants came from neutral sources such as the National Science Foundation.

By contrast, university agricultural research and big business have a long history. Ag campuses and scientists claim to be neutral, but they're human and they know that a history of findings that don't support industry sponsors will result in fewer research dollars.

What are the consequences if the science is true? This question is more subjective than the other two, but I consider it a valid qualifier.

• Climate science: Accepting climate change has already meant more diverse and stable energy sources and less dependency on the whims of unstable regions such as the Middle East. People who drive less and walk or bicycle more are healthier. Core cities are being redesigned to accommodate people instead of automobiles. Energy efficient light bulbs and appliances are saving money for consumers.

• GMO foods: GMO foods are patented and Monsanto, the food giant with the most profitable patents, filed 144 patent infringement lawsuits against farmers in a 13-year period. What this means is that you can't save seeds that have GMO properties and use them to plant next year's crops unless you pay a royalty to Monsanto. That concentrates the power to farm into the hands of a few large companies.

The ag industry tells us that GMO foods are essential to feeding a growing world population, an argument it used years ago on the importance of using toxic pesticides. How many more suspect practices will we have to accept if we continue down this road?

Some would say that people like me, who trust one science and not the other, are being inconsistent. I will argue that we are distinguishing between science that has shown consistent results and science that has been unreliable and probably tainted by a profit motive.

Doug Shidell, of Minneapolis, is publisher of Bikeverywhere.