I am confused about the climate change debate, and most readers have greater aptitude in science than I do. So this is a sincere request for input.
All of the debates I have heard about global warming involve the data. Are historical measures accurate? Are computer models complete enough to accurately forecast trends? UAH’s Christy has attained considerable notoriety by challenging the data. “Climate-gate” suggested there were efforts to manipulate the data to buttress claims of anthropogenic (man-made) warming.
My confusion has to do with the relevance of the data. Obviously, many factors affect climate. No matter how significant human-caused greenhouse emissions are, natural factors could still cause a downward trend in temperatures. The issue is therefore, I would think, not whether there is an upward trend in temperatures, but whether human activities affect the temperature that would exist absent those activities.
That is not an issue that we can resolve with data, unless we understand every factor that impacts atmospheric temperature. We don’t.
So we have to look at what knowledge we have. We know, I thought, that carbon dioxide allows passage of sunlight. We know that some solar radiation, when it hits the Earth’s surface, converts to infrared radiation. We know that carbon dioxide tends to block the escape of the infrared heat energy from the atmosphere. We know that human activity increases the amount of carbon dioxide, relative to the amount that would exist without human activity.
Given that knowledge, haven’t we proved the existence of anthropogenic climate change, regardless of the data?