There is an economic number that is giving me nightmares. I stumbled on the number in an article by Bill McKibben in Rolling Stone in July. He got it from a London research organization called Carbon Tracker Initiative. Let's see if I can give you nightmares, too. The number is US$20 trillion. That's about 20 years' worth of U.S. Deficits. It is 30 times the Canadian national debt. It is 150 times the value of all the gold taken out of Northeastern Ontario in the last 100 years. It's the kind of money that people kill for.

Economists believe that people respond to economic incentives. Twenty trillion would provide a pretty powerful economic incentive to lie, bribe, and even to let people die. Twenty trillion would pay for a lot of propaganda, and in the U.S.A. it would buy a lot of congressmen.

It is also the value of just 80 per cent of the value of the proven coal and oil and gas reserves owned by private and public companies and governments.

Why focus on 80 per cent of the value of reserves? Because 80 per cent could disappear.

You probably know that most scientists think we have to limit global warming to two degrees to have a reasonable chance of avoiding catastrophic climate change. Politicians at the Copenhagen climate conference in 2009 agreed with the scientists. Add or subtract half a degree if you don’t trust the science. It won’t affect the story.

The Potsdam Institute for Climate Impact Research figured out that there is a four in five chance that we can avoid crossing that dangerous line if we limit the world's carbon dioxide release between now and 2050 to about 565 gigatons. Again, you can add or subtract a few hundred gigatons – it won’t affect the story. The main thing to notice is that 565 gigatons is a small fraction of proven coal, oil and gas reserves.

If we can only burn 20 per cent of the current reserve, 80 per cent becomes stranded assets. They can’t be sold. The people who own those stranded assets lose $20 trillion.

The owners of all those reserves pay huge salaries to their CEOs to maintain the value of their assets. Their highly competitive CEOs eagerly donate money to anti-carbon-tax politicians and to climate change deniers like our own Mr. Stephen Harper. They fund TV ads promoting tar sands projects for the jobs they create. They pay for two-page spreads showing the beautiful artificial lakes they plan to create.

You can see why $20 trillion is giving me nightmares; $20 trillion is a whopping big incentive to deny a lot of very convincing science.

But the story gets worse. An unjustifiable run-up of prices is called a bubble. Bubbles burst. Bursting bubbles can bring on depressions. When the U.S. housing bubble burst in 2007, it caused the biggest financial crisis since the 1930s. In one day, total U.S. stock market losses exceeded $1 trillion. The world economy has not recovered. The value of sub-prime mortgages in the 2007 crash was only about $1.2 trillion and only part of that was really lost.

So here we are between a rock and a hard place. On one side we have some of the smartest people in the world telling us not to burn $20 trillion worth of carbon. On the other side, we have a potential financial collapse because some of the most powerful people in the world believe that we can burn all that carbon. When and if they realize we can’t, financial markets could collapse.

The financial impacts are the subject of Carbon Tracker's recent research paper called Unburnable Carbon –Are the world’s financial markets carrying a carbon bubble? The paper calls for major reform of the world's financial markets. Unfortunately, reform in the financial markets is like Paul Ryan’s mountain climbing achievements – more aspiration than accomplishment.

But all this leads to one surprising conclusion. The first carbon assets to be stranded will be high-cost, high-carbon reserves like Alberta’s tar sands. It is probably a good idea to sell them off to foreigners as fast as we can. The Nexen sale may be a good way to protect a lot of American investors from a bursting bubble.