Small temperature change having a large effect: consider two blocks of ice, both starting at the same temperature and other conditions, say, -0.1 C.

Block one - maintain the same temperature.

Block 2 - raise the temperature by 0.2 C.

What is going to happen over time?

Another example: consider a large, enclosed room filled with flammable material, like paper.

Raise the temperature of 0.1% of the room by 250 C, an average increase of 0.25 C.

Mountain pine beetles: this devastation (283 million cubic meters of timber have been killed so far in BC alone) is happening because for many years there have not been any stretches of two or three weeks or more with temperatures below -30C or -40C, something which happened regularly in the past. The low temperature penetrates the trees to where the beetle larvae are overwintering and kills them.

There are many, many other examples of such changes, but I get the feeling that you would attribute all of them to natural cycles.

You mised my point about car fuel economy - car companies in the past complained that they would go broke trying to meet newer standards of fuel economy, just like all the complaints today about the economy tanking if Kyoto or similar reductions were to be attained. The car companies - at least the smart ones - are thriving, and so would many areas of the economy should CO2 and other emissions be reduced effectively.

(I agree that nuclear power would go a long ways to reducing CO2 emissions)