Earth Hour: The Friend and Foe of Climate Change...

Last March, the inaugural worldwide adoption of Earth Hour took place, as millions throughout the world turned off their lights for one hour to create awareness about global climate change. While much awareness was created, there was also a significant reduction in electricity consumption, as high as 8.7% in Toronto.

However, as Benjamin Dachis indicated in his 2008 special piece to The Globe & Mail, there was an unexpected and counter-productive side effect of Earth Hour, in Ontario at least. While logical thought would provide a correlation between electricity reduction and a reduction in greenhouse gas emissions, it was actually the opposite that occurred. Earth Hour actually produced more greenhouse gas emissions than during non-Earth hour times.

Wait. What? How?

It has everything to do with the way the Ontario electricity grid works. Ontario relies predominantly on a mix of nuclear, coal and hydroelectric power. Nuclear and hydroelectricity produce roughly no carbon emissions, while coal is one of the dirtier villains (Premier Dalton McGuinty has promised--many times--to shut down the province's coal plants).

Nuclear and coal plants generally run quite consistently and changing the amount of output from these plants can be expensive. Shutting down a nuclear plant for a day (and subsequently starting the thing up) could cost millions of dollars. Hydroelectricity, on the other hand, is much more cost-effective to change output. All you need to do is turn off the turbines and the water will keep flowing anyways.

So when demand on the grid changes (like when hundreds of thousands of people turn off their lights for an hour), it isn't the dirtier, carbon-emitting coal plants that get turned down, but the emissions-free hydroelectricity. As a result, the proportion of power coming from coal increases and often the absolute levels of coal-sourced power actually increase as well (as high as 18% in Ontario during Earth hour, primarily as a result of exports to the U.S. that night).

March 28th is the date of this year's Earth Hour. So when all the lights go out, just remember that there is a small price for the wonderful awareness campaign that is Earth Hour.