In "Be cautious on climate change" (Opinion, April 13), Rep. Chris Stewart has lots of concerns about whether man is causing the Earth to warm. I am concerned he only questions one side. Here are a few questions he might ask the skeptics:
There has been a 40 percent increase in CO2 levels in our atmosphere. I've never heard a scientist challenge the idea that Earth would be colder without CO2. If the rise of CO2 is not a concern, at what level did it stop affecting our climate?
An oft-heard theory is that volcanoes, not humans, are to blame for the rise in CO2. Why didn't CO2 levels jump with Mt. Pinatubo's enormous 1991 eruption?