“Over your lifetime, your individual greenhouse gas contribution will only increase the temperature of the planet by about a half a billionth of a degree Celsius. That, you might think, is such a small difference as to be negligible, so you shouldn't bother trying to reduce your personal emissions. This reasoning, however, doesn't consider expected value. It's true that increasing the planet's temperature by half a billionth of a degree probably won't make a difference to anyone, but sometimes it will make a difference, and when it does, the difference will be very large. Occasionally , that increase of half a billionth of a degree will cause a flood or a heatwave that wouldn't have happened otherwise. In which case the expected harm of raising global temperatures by half a billionth of a degree would be fairly great. We know that something like this has to be the case because we know that, if millions of people emit greenhouse gases, the bad effects are very large, and millions of people emitting greenhouse gases is just the sum of millions of individual actions.” Climate ChangeGlobal WarmingTragedy Of The CommonsGlobal Catastrophic RiskExpected HarmExpected Value Book:Doing Good Better: How Effective Altruism Can Help You Make a Difference Source: Doing Good Better: How Effective Altruism Can Help You Make a Difference