> That said, the climate models tell us very little useful information we didn't already know. I don't think they have much policy impact.

You're wrong in thinking so, these models have an enormous impact since they are what are being used as 'scientific evidence' for the current 'climate change' craze. Without these models there would be only those measurements you mention which in no way indicate the type of trends which the models are being used to warn about. All the measurements show is that it sometimes gets really warm, sometimes really cold, sometimes really windy and sometimes really dry. Measurements do not show a steadily and unerringly upward climbing curve of 'sometimes really warm' and - important in this context - they do not show the current period to be the extreme which it is made out to be. Taking the continental USA as an example - an area for which much data has been collected in a standardised fashion for a long time, making such comparisons possible - it is noticeable that most temperature records - high but also low are found in the early 1900's, mostly centred around 1936 [1]. If you look at newspapers from around that time the tone was comparable to what it is now (in more ways than one given the threat of war on the horizon but that is unrelated to this issue). Looking back further it can be seen that the average temperature has been steadily dropping (as "average over many years", not "average of the last 5 years") since about 8000 years ago when the climatic optimum is to be found [2] somewhere. It is also noticeable that this temperature decline does not follow a straight line, sometimes the average temperature was supposedly - these measurements can only show averages over longer time frames, not year by year - higher than the average during the optimum, sometimes they were lower. The trend is clear and is pointing downwards towards the coming glaciation, whenever that may be. Without the models to use as 'evidence' there would be no 'climate deniers' (an astoundingly dishonest term since most people who are called such do not deny anything about climate, they just do not trust these model calculations with good reason) since current phenomena would just be "weather", not "proof of climate change" - just like they were in the early 1900's.

These models are The Science™ for climate alarmists, no more and no less. They are not the oracles of wisdom as they are made out to be since they suffer from the Garbage In, Garbage Out problem like so many other simulations. As such they are not good tools to use to direct policies but more clubs to wield against recalcitrant opponents.

Does this mean the climate does not change? No, it does not, it changes as it always has and may change in the direction the model calculations show, at least for a while - look at the variations in [2] for an indication of such changes - and it makes sense to prepare for the consequences of a warmer - or colder - climate when possible. Does this mean there is no need to cut 'emissions'? No, it does not mean that either, there are other good reasons to reduce those since these emissions do not just consist of CO₂ but encompass other substances which are actually polluting. It does mean that the laser focus on 'cutting emissions' is most likely the wrong approach since there are far more effective ways to prepare for the effects of a changing climate. No amount of emission reduction will stop the next Katrina disaster but raising levies will, no amount of extra carbon taxation will solve the problems caused by drought but investing in desalination plants [3] will, no milestone in electrification of road vehicles will help with dealing with increased precipitation but upgrading storm drain systems will, etc.

There are other reasons to want to reduce the dependence on fossil fuels as can be seen in Europe which had become unhealthily dependent on natural gas from Russia or the many wars fought by the USA to secure the supply of oil from the middle east - these substances often end up being used as tools to achieve some geopolitical end. Reducing these dependencies where economically feasible is a good investment in future stability and security.

Many of the mentioned reasons - and more - speak for a reduction in 'emissions', they just do not focus on CO₂ as being the reason for reducing them. What all these reasons lack is a sense of urgency and that is most likely why these models are used in their stead. It is much easier to get people scared, then tell them what they have to do to feel safe again than it is to try to convince them of the wisdom of reducing pollution and reducing dependencies for a more stable future.

[1] https://en.wikipedia.org/wiki/U.S._state_and_territory_tempe...

[2] https://en.wikipedia.org/wiki/Holocene_climatic_optimum#/med...

[3] ...yes, yes, they produce brine which needs to be handled in some way - this can be solved in many ways so