Next year could see markets start to wake up to a proper carbon bubble: the inflated value of hydrocarbon-heavy corporates.
Fossil fuel companies may already have found more coal, oil and gas than can safely be burnt without prompting damaging climate shocks. A 2011 report by Carbon Tracker, an environmental think-tank, found 745 giga-tonnes of carbon embedded in the proved reserves of the world's biggest listed coal and petroleum companies.
That was almost a third more than the 565 giga-tonnes that some of the best available science suggests can be burned before 2050 without running significant climate risks. Add in reserves held by unlisted companies and governments and the embedded carbon figure hits 2,800 giga-tonnes. And that's just known, recoverable deposits. Prospectors make new finds all the time.
It presents a conundrum for investors, who tend to value energy companies based on the expected cash flows from their reserves. If the fossil fuel has to stay in the ground to save the planet, so does the cash.
So far there's been little reason to worry about the disconnect. But three things may prompt a rethink.
First, it's no longer just environmental campaigners sounding the alarm. In its November world outlook, the International Energy Agency threw its weight behind the carbon bubble math. That can only embolden activists pushing for more aggressive accounting for carbon risks in company reports.
Second, high food prices from the summer's severe drought and the after-effects of Hurricane Sandy are likely to persist well into the New Year, offering a reminder about the kinds of disruption scientists expect to become more common on warming planet.
Finally political attitudes in the United States, a long-time climate-change laggard, are shifting. Nearly two-thirds of U.S. voters in a November poll said the government should address the issue. Three years ago, only a small minority were concerned. It's not inconceivable that President Barack Obama might embrace carbon pricing, as a tool to combat emissions, in his second term.
A final decision on TransCanada's Keystone-XL pipeline, expected in early 2013, will test the new mood. If the Obama administration kills the controversial oil sands conduit, investors should start applying a steeper discount to expected cash flows from carbon-intensive fossil fuel deposits.