> I'd be really interested in why climate change is a hysteria and not well-founded fear.
There are different types of criticism re: the claim of Anthropogenic Global Warming (which I'll refer to as APGW) & it's impacts. Mainly b/c APGW is a composition of claims, many of which are criticized to varying degrees.
My perspective is that throughout Earth's history, the climate has always been under a perpetual state of change, sometimes to far more drastic degrees than what we are witnessing today. About 200 years ago, we left a mini ice age (i.e. "the year without a summer"), which means that this point in the natural cycles is one of warming. I'm far more concerned about events coming from outer space & Sun, the current Geomagnetic excursion, & pollution than APGW. Other planets in our solar system are going through intensifying climate change right now.
I'm not confident that the state of climate science accounts for all inputs into the cycle...looking at the Sun's cycles, our changing position within the cosmos, cycles external to our solar system and the impacts on Earth's climate. Climate models have a terrible track record with predicting future trends. This complex system, where all of the inputs are not yet properly modeled, is not modeled in a way which gives predictive value. The media & politicians tend to sensationalize the most extreme "doomsday" models (i.e. Al Gore stating that snow will be a thing of the past & the glaciers will all melt by 2020).
The natural cycles (there are many factors) are also not properly modeled, as we have only had precise measurements & can only date ice core samples, for a period that does not incorporate a single period for each of the cycles.
The oceans are also a large reservoir of CO2 & CO2 escapes a liquid as the temperature rises. Given we have geologically recently left an ice age, CO2 will naturally escape from the oceans. I wonder if a large portion of the rise of CO2 comes from global warming (with CO2 escaping the oceans) and not the other way around.
There have been experiments that show that CO2 does increase the temperature of a system to some extent, but the warming has upper-bound limits & it is not a runaway phenomenon. I confirmed this by doing a PV=nRT & CO2 delta calculation on Venus & found that if CO2 is a runaway phenomenon, the temperature on Venus would be significantly higher than it is now.
That being said, experiments show that an increase of CO2 does increase the temperature of a system, but not in a runaway hockey stick graph sense, but in a logrithmic upper-bound sense.
My experience with many people is that they want to simplify their understanding of complex systems in a lossy manner. I feel like many of the fears around APGW is a lossy simplification that attracts people to make sense of nature's complexities. It is psychologically difficult to admit & consciously regard there is much that we don't yet know & are not accounting for..even more difficult to admit that Earth has had numerous widespread natural catastrophes that we would not be able to control. We want to be able to predict the future with our models, the simpler the model the better. The problem is sometimes the system being modeled is very complex & we have not yet recorded all of the cycles involved or accounted for all of the inputs. It is psychologically attractive & consistent with history for cultures to create a scape goat which must be sacrificed to appease the Gods & forestall impending doom.