Judy Curry comments on a new IPCC report: natural variability accounts for a lot of change that is observed; er, possibly all?
I think we're getting closer to an agreement by reasonable people that very little is known about the climate of the entire world.
1. Man-made CO2 has gone up--obviously, but probably it is retained in the atmosphere in a way that can be quantified. This was a discovery that took a lot of work, and I believe it was made before the boomers took over the field.
2. There was probably a medieval warming period over much of the globe, comparable to the 20th century. Again, a pre-boomer discovery. Obviously any such warming period would have nothing to do with man-made CO2.
3. A simple high school experiment can demonstrate that with an attempted simulation of the earth's atmosphere, if you increase CO2, the temp goes up. It is not clear that this has ever happened--even once--in the real world. In other words, even before man-made CO2, did CO2 itself ever directly cause a temperature increase net of other contributing factors? Gore's famous graphic, based on Greenland ice cores, shows the opposite--first temp increase, then CO2 increase.
4. The period since 1850 has been possibly the best period ever for human life on earth--at least in a material sense. We live longer--usually the gold standard for measuring the health of a population. Contrary to predictions when I was in high school, we produce enough food for the population. Classic local pollution from factories and vehicles gets better with increasing wealth. Big, non-local environmental scares have tended to be bullshit: acid rain, widespread species extinction, forest extinction/monoculture, global warming. Maybe CFCs/ozone was not bullshit, I'm not sure.
5. Has anything both significant and bad happened even in co-relation with man-made CO2? If not, of course there is no cause and effect.
6. Environmental initiatives have tended to be a transfer of wealth from the poor to the rich. Biofuels is the worst--converting food-producing land to fuel-producing land, increasing scarcity and starvation among the very poorest people on earth.
7. Anything new that has been added to this field by the boomers is largely bullshit.