Hypothetically, switching off the lights for an hour would cut CO2 emissions from power plants around the world. But, even if everyone in the entire world cut all residential lighting, and this translated entirely into CO2 reduction, it would be the equivalent of China pausing its CO2 emissions for less than four minutes. In fact, Earth Hour will cause emissions to increase.
As the United Kingdom’s National Grid operators have found, a small decline in electricity consumption does not translate into less energy being pumped into the grid, and therefore will not reduce emissions. Moreover, during Earth Hour, any significant drop in electricity demand will entail a reduction in CO2 emissions during the hour, but it will be offset by the surge from firing up coal or gas stations to restore electricity supplies afterward.
And the cozy candles that many participants will light, which seem so natural and environmentally friendly, are still fossil fuels—and almost 100 times less efficient than incandescent light bulbs. Using one candle for each switched-off bulb cancels out even the theoretical CO2 reduction; using two candles means that you emit more CO2.
What I could get behind is a “Night Sky Hour” or something similar in which people would shut off outdoor lighting for a specified period of each night or of one night a week to cut light pollution during that time. Night pollution is a huge negative externality and many sources of it do little other than create such pollution (since the impact of home and street lamps on safety are very much overrated).
Here is what I said last year on light pollution:
Light pollution which brightens the beautiful dark sky with an ugly muted glow is one of the most underrated negative externalities around. I talked a little bit about this earlier. Unfortunately, it is a really difficult problem to solve.
On the one hand, Coasian bargaining can’t solve the problem given the huge transaction costs of dealing with the millions of people who cause the natural dark sky to disappear (not to mention that a property right in the skies relevant to this issue can’t really be defined or allocated easily unless you gave someone a near monopoly grant).
On the other hand, even government solutions would be resisted by the “cult of light” that has formed around the notion that we need artificial lighting outdoors in order to be safe and secure (or to properly advertise business activity). I can’t imagine a tax on improperly shielded outdoor lights large enough to change behavior and decreasing light pollution would be very popular with the electorate. And light fixture and bulb companies would almost certainly use their vast lobbying power to help kill such a tax even if it had an electoral chance. That leaves regulation – which might suffer from the same political barriers – and education.
Of course, someone might argue that the harm done is so small in the aggregate that it isn’t even worth a political decision costly to the preferences of many more people. Maybe so, even though I generally reject utilitarian defenses of any particular act or policy.
So I think we are stuck for the immediate future with the ugly sky we’ve created through the millions of innocent and often well-intentioned decisions of market participants that harm others without compensation.
Perhaps “Night Sky Hour” would be some compensation for those of us harmed by this externality?