There's two key points he misses out on:

1. A lot of models based on climate change are based on worst case scenarios. There are also business as usual models, 10% reduction in gases, 20% reduction etc... all prone to standard error margins. Things may not have been as bad as predicted that they could have been with nothing done, but I'll think you'll find that's because we didn't go down the worst case scenario route.

2. Climate change is not the only incentive for reducing emissions. Sustainability and economic factors play a big role. For instance if your car produces less emissions, it's because it is using less fuel or using it more efficiently making it cheaper for the consumer and wasting less of a limited resource. The population is growing, our resource base not so much for some, critically less for others. In order to create a sustainable environment we need to use our resources much more efficiently - and this generally comes about by using less fuel, producing less waste i.e. the same things that go about preventing climate change. Even if climate change is proven to be a complete hoax, there are still other reasons to implement many of the measures used to combat it.