This mashup from Malcolm Daniel is a great 4-minute summary of the film:

Two things particularly struck me:

Firstly, Gore presents evidence from Antarctic ice cores, showing the atmospheric CO₂ levels over the last 650,000 years. Recently, certain climate-change sceptics have tried to throw doubt on the nature of the human-induced global warming by citing cyclical events through the Pleistocene glaciation. This graph indeed shows such cyclical events with glaciations interspersed with interglacials.

See also 600,000 year graph.

However, look at present-day CO₂ levels, at 380ppm, much higher than the historical maxima of around 280-290ppm. We are not in a cyclical interglacial, but in completely new territory.

The second thing that struck me was the fact that we have the technology, right now, to solve the problem (or at least to mitigate the worst effects). We don’t need mirrors in the sky, we need simple measures, but taken by everyone. These include energy-efficient appliances, industry and transport; renewables; and even carbon sequestration. With these, we can reduce our CO₂ emissions to 1970 levels!