–by Mark Shields
I think we may need more choices than cause = CO2, cause = natural variability, and cause = unclear, for those who think there is warming; I don’t feel these options exhaust the interesting set of “causes”. I personally think, whether at any given moment the temperature trend is up or down, that the absolute level is higher than it would have been without mankind liberating large amounts of stored (chemical and nuclear) energy via Fossil Fuel, Fission and Fusion (FFFF). This concern is completely different than the concern about CO2 levels, and I think is an easier way to frame the pertinent question about what we should be doing about our use of energy.
These “FFFF” energy sources borrow from ancient reserves of potential energy and release this energy in the present timeframe at much higher rates than would have been the case otherwise (without human participation in the cycle). In contrast, rapidly cycled solar energy flux captured in the form of wind, solar, hydro-electric power (and even wood heating), is solar energy temporarily forced to do human directed work before being largely transformed back into heat within timeframes comparable to those in which mother nature would have done the same.