As a climate scientist, I hear my share of myths about what is causing climate change or why it is a “hoax.” I call them “zombie theories” because they just will not die. They persist in blogs, certain networks, and social media like zombies long after scientists have killed them off. I debunked 20 of them in a previous article in Forbes. The “sun and its variability” is one that makes the rounds. I am pretty sure I’ve had to spray “climate science repellent” on that nagging “mosquito” numerous times. This week I heard of a variation of this myth involving cosmic rays. Here is a science-based debunking of the solar-cosmic ray myth.
I won’t spend time highlighting any particular zombie theory about the Sun or cosmic rays. It is more useful to “cut to the chase” on why the Sun doesn’t explain climate warming. The graphic below from a NASA climate website is the basis for the discussion. Solar energy is a very important part of our weather-climate system, but I find that some people don’t have a clear understanding of its role.
There is misconception that because we feel heat from the Sun and see it in the sky it represents how Earth’s surface is warmed at all times. It is actually far more complicated. The Earth has an atmosphere with relatively small amounts of greenhouse gases like carbon dioxide, methane, and water vapor. However, don’t be filled by “relatively small” because they are important. Colorado State University professor Scott Denning often says, “We survive every night because of the Greenhouse Effect.” His point is that without the system of gases absorbing and re-emitting longwave radiation (heat) it would be too cold to survive. The energy from the Sun varies, and the 11-year sunspot cycle is a primary driver.