So it seems a number of my ideas just aren't going to work out.
The melting of the north pole did not occur as fast as was predicted. It was predicted to have completely melted by September of this year. It is now October, and there is still ice on the pole. Less than there was before, and it's still decreasing in an alarming way, but ice remains.
The Radioisotope car would work if most people drove it for what it was, a dangerous and powerful machine. Unfortunately, a look into urban traffic quickly shows that people make excessively risky maneuvers with their car all the time. When their car is powered by hydrocarbons, the way it is now, the absolute worse case error involves their car exploding, potentially killing everyone inside it. Sad, certainaly, which is why they tell you to drive carefully, but not risky to anyone not directly in the car's path.
Radioisotope cars would have a small amount of nuclear waste in them. This waste could be contained so that it would survive a collision with another car without damage, say by using a tough metal alloy. Nuclear waste is currently transported in containers that could survive a direct hit with a minor explosive. Unfortunately, I imagine that if I actually made and sold radioisotope cars, that some fool would attempt to "race the train" by slipping through the safety bars that urge you not to do that and try to make it through the intersection before the train goes through. Trains often go as fast as 90 MPH and weigh hundreds of times more than any car. When a very large, very fast moving, very heavy object collides with a lighter object, simple physics can tell you that the lighter object is going to be pretty much destroyed. So now we have a hazmat emergency, because I can't think of any material offhand that could survive being hit at 90MPH by a train. Raw plutonium on the road would be a horrific emergency for the entire city.
Also, due to power-to-weight ratios, large trucks and large SUVs would be far more practical to isotope-power than station wagons. This style of vehicle is going out of style.
So Radioisotope power should be more restricted to home applications, where it is less likely to be rammed with trains, thrown off cliffs, or run into a wall because somebody decided to go faster than they could readily perceive and interpret.
Although the two could combine again with better batteries, with radioisotopes providing your home power which you use to charge up your electric car's battery.
On the plus side, two of my ideas were used successfully by other people.