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?
Some say increased solar activity is the real culprit behind global warming. If so, all of the atmosphere should warm. In contrast, if CO2 is the cause, temperatures should rise only in the lower atmosphere. That's because as the Earth emits heat, CO2 intercepts some of what would otherwise go to the upper atmosphere. The stratosphere is cooling. How can high solar activity explain this?
Let us know if you get reasonable answers to these questions.