Interesting Argument About Global Warming - Challenged

I 'stumbledupon' this video which concerns the human contribution towards global warming, and the arguments behind what our actions should or should not be. Despite ultimately agreeing with the conclusion offered in the video, I find the basis for the argument put forward fundamentally flawed.

The proposition offered by the commentator goes something like this:

What should we be doing about the (theoretical) threat of global warming, whether its effects are enhanced or not by human race? At a basic level, our options can be divided up into four groups which can be visualised in a two-by-two grid pattern -

scenario 1 - that human global warming theory is wrong but we act anyway by investing heavily in clean power, reduce CO2, etc. result: the huge costs involved lead us into global economic depression.

scenario 2 - that human global warming theory is correct and we take the appropriate action by investing heavily in clean power, reduce CO2, etc. result: the planet is saved through our actions.

scenario 3 - that human global warming theory is wrong and we take no action. result: life goes on as normal.

scenario 4 - that human global warming theory is correct but we take no action. result: floods, famine, wars, death and destruction.

Where I see a glaring flaw is where scenario 1 leads to economic doom because of the costs involved in the global change in energy production/usage, etc, but scenario 2 doesn't. Surely if scenario 1 is correct then logically scenario 2 should also lead us into a great depression also, with the only difference being that we would have saved the planet in the process.

What the commentator fails to appreciate is the fact that the global economy is going to, if anything, improve due to the new industries and markets created by alternative fuels, recycling patterns, etc. Whatever jobs or revenues are lost due to us dropping fossil fuels, for example, will be easily made up by the shift to solar, wind, wave or bio-fuel technology and production. There will be a worldwide market for environmentally-friendly measures and so the usual supply-and-demand requirements will still exist. They would have just shifted from dirty to clean energy, etc.

Why is it that people have allowed themselves to believe that clean energy, environmental cleanup/protection, alternative raw materials and all the rest is bad for the economy? And even if they were bad for the economy, what use is that economy if human-influenced global warming is going to wreck the planet in the near future?

As the video concludes, regardless of what we currently believe, we have to get on with the change to a green global economy. The effects of pollution and fossil fuel shortages alone should be enough for us to take this path anyway and I'm sure we'd be well on the way down it if it wasn't for big business blocking our journey and feeding us with disinformation, aided by self-interested politicians and lobbyists.