People opposed to action on global warming use three arguments most often: global warming is not caused by human activities, reducing CO2 will slow economic growth and really it's just an excuse for eco-liberals to create a neo-fascist nanny state to run everyone's life in an irritating and politically correct fashion.

There isn't much I can add to the debate on the first issue, but let's talk about the other two, with the help of the graph above which I found at the Canadian Green Party website.

We'll see that reducing CO2 by increasing energy efficiency improves the economy and that 'nanny' laws work when the free market doesn't.

That blue line going down shows the dramatic improvement in the energy efficiency of refrigerators in the US since 1973. That pinkish line rising tells an opposite story -- of the dramatic rise in standby power over the same period.

Together they tell a couple stories: one about vampires, the other about nannies.

We have come to a point in the election season where the courage of the candidates and the intelligence of the voters are being severely tested. So far, the candidates are flunking. The public’s grade is pending.

The test is about oil and national security.

An old friend of mine used to say that at a certain stage in political campaigns, dead cats start flying through the air.  I’ve never understood what he meant by that, but I think the cat-flinging has begun.

Both candidates are doing their share, but one exchange deserves special analysis: John McCain’s attack against Barack Obama’s comment about tire gauges. In one of his recent energy speeches, Obama made the point that acts of conservation by individual Americans can have an impact on rising oil prices. He used tire pressure maintenance as an example.

Cement is at the heart of increasing global warming emissions. It's production releases large amounts of CO2 -- both from the chemical process that creates it and the energy consumed in manufacturing. China alone makes 45% of the world's cement, and globally the industry is booming.

That's why two promising new developments related to the production of cement - an ancient and mundane material -- are drawing attention. Reducing CO2 from making cement isn't as sexy as electric cars, but it's the third largest US CO2 producer so there’s an opportunity to make a real contribution.

You've heard about Al Gore's challenge to remodel the U.S. electrical industry in 10 years to eliminate all CO2 emissions. Some commentators say the job is too big, some say it isn't, but everyone, including Al, agrees it's a big, big job.

But exactly how big? What are we up against here? How much new wind, solar, geothermal power do we need to replace the CO2 producing plants? What else might be needed to make such a system work?