I've gotten myself caught up (as well as a non-expert can be) on the science of global climate change and the history of public sentiment. Here are the facts, as I see them.

* Global climate is very likely the most complex system we've ever attempted to understand. Literally every scientific discipline-- physics, chemistry, biology, geology, astronomy/cosmology, you name it-- plays a crucial role in understanding the small processes that accumulate and interact to drive local and global climate.

* Many of those disciplines have worked extremely diligently to understand the science behind all of the elements that come into play: carbon release and absorption, the effect of greenhouse gases and particulates on solar radiation and global water/air currents, the CO2 aborption rates of biomass, CO2 sequestration in the ground and especially the oceans, effect of tiny orbital perurbuations and solar cycles on atmospheric temperatures, the use of surrogate measures such as ice cores and tree rings to stand in for historical temperature records . . . it goes on and on. The science for all of these has gotten better and better and this work is worthy of the very highest respect. Intelligent and well-meaning scientists have dedicated their lives to this and they should be praised for it.

* This science points to a convincing picture that shows that man can influence global climate. I'm fully convinced that we can, and we are, affecting climate both locally and globally with our actions. The volume of our activity is large enough to affect CO2 levels in the atmosphere-- I think that has been demonstrated. I'm convinced that we should act to reduce emissions on the basis of the links that have been established.

* HOWEVER . . . the alarmism is not based on good science. The models that show catastrophic temperature change have, to date, made lousy predictions of actual future temperatures. Climate has proven to be far too complex to model with much precision, even if all of the inputs are well understood (and I'd argue here that some are and some aren't, and most are unpredictable on top of that). The CNN opening line-- "Flooded rail lines. Bigger, more frequent droughts. A rash of wildfires"-- those are predictions that are based on flawed models. Those things could happen and may happen if climate changes as the models predict-- but so far climate has not changed as the models predict.

Unfortunately that last bullet qualifies someone as a "denier." I am all for change, but the balance between economic considerations, the ability to feed the world's citizens, and environmental policy is a delicate one, and should be discussed honestly and without raised voices and insults. Unfortunately the hysteria no longer allows this.