EVEN by the standards of recent periods of extreme weather, this summer has been a doozy. High temperature records have been broken around the globe. Arctic sea ice is tracking record low levels. America has been battered by wildfires and freakishly strong storm systems. And an ongoing American drought is sending commodity prices soaring and threatens to match the Dust Bowl in intensity. No single weather event is "caused" by global warming. But warming raises mean temperature and increases the incidence of extreme temperatures and weather events. Warming bears some responsibility for this year's dramatic weather, and there is worse to come. The New Yorker's Elizabeth Kolbert writes:
One of the most salient—but also, unfortunately, most counterintuitive—aspects of global warming is that it operates on what amounts to a time delay. Behind this summer’s heat are greenhouse gases emitted decades ago. Before many effects of today’s emissions are felt, it will be time for the Summer Olympics of 2048. (Scientists refer to this as the “commitment to warming.”) What’s at stake is where things go from there. It is quite possible that by the end of the century we could, without even really trying, engineer the return of the sort of climate that hasn’t been seen on earth since the Eocene, some fifty million years ago.
There is much more warming already baked into the cake based on the carbon that has been released into the atmosphere. Bill McKibben writes that so far, the global temperature has risen 0.8 degrees Celsius, and that the carbon already emitted into the atmosphere will probably generate another 0.8 degree increase—distressingly close to the 2-degree threshold governments have agreed would be too risky to cross. To keep the world below that threshold, Mr McKibben says, would require humanity to limit future emissions to an estimated 565 gigatonnes of CO2. But if you estimate the emissions that would be generated by burning all the fossil fuels in the known reserves of private energy companies and sovereign governments—just the known reserves—that adds up to 2,795 gigatonnes of CO2.
It's hard to know what the world would look like under that emissions scenario. It would be an alien place. Conceivably, a sufficiently technologically sophisticated human race could adapt and avoid extinction. To imagine that adaptation could be accomplished without staggering human and economic cost is all but impossible.
So to avoid probable disaster, humanity must find a way not to burn some 80% of proven fossil fuel reserves (or to suck the resulting carbon out of the air and put it somewhere it won't do damage). How to do that?
Five years ago, I would have said that the most promising route forward was to develop a global carbon price while increasing investment in basic energy research. I still think a carbon price, set by tax or cap-and-trade plan, is a no-brainer of a policy. It would raise revenue more efficiently than other taxes while ensuring that the lowest hanging emission-reduction fruit was plucked. But I no longer think it is remotely adequate as a solution to global warming. For a carbon price to work on a very short timescale it would have to be very high, which may or may not be economically problematic but would surely be politically inoperative. For a carbon price to work while starting from a low level would take a long time, and time is in short supply. In 20 years the geese may already be cooked (and the bears and crops and coral with them).
Behavioural change isn't going to work fast enough. What's necessary are new technologies that can make a difference right now. Cheap, reliable, zero- or low-emission energy sources that can be plugged into the grid at rates that make fossil-fuel power look like a boondoggle. Zero- or low-emission vehicles that can be put on existing transport infrastructure. And innovative new technology that can pull carbon out of the air and put it back safely in the ground.
Easy, right? The temptation upon considering needs like those above is to call for a "Manhattan project" approach, throwi