Until all the evidence is in

Nobody actually waits until all the evidence is in. The simple reason is that all the evidence will never be in. For that to occur one would have to know about everything going on in the universe right now and where those things would lead in the future. For Earth-bound residents, perhaps it would be sufficiently rigorous to know everything that is going on in the solar system and its future.

What do people mean when they say they want to wait until all the evidence is in? Most often they mean they want to wait for more information. But, sometimes they mean nothing of the sort. Sometimes they mean they want you to wait until all the evidence is in before you proceed to do something they don’t like. In other words it’s a stalling technique, one used quite effectively by the fossil fuel industry to prevent meaningful action to control greenhouse gasses.

The implication behind this ruse is that public policy is made based on all the evidence. But this has never been the case and never will be the case. Public policy is made based on incomplete information and perceived probabilities of gains and threats. (It’s also made based on the influence of powerful interest groups; but that would require a discussion all by itself.) This is why modeling has become such an important tool for those involved in climate and energy supply research. If we had all the information, we wouldn’t need models that announce possible outcomes based on incomplete information.

So, if we can’t wait until all the evidence is in, what standards should we use to guide our decision-making, both in public policy and in our daily lives? I would propose two that we already use. First, unlike the standard for criminal court cases which rightly requires jurors to judge someone guilty beyond a reasonable doubt, civil cases require only a preponderance of evidence for a party to prevail. When it comes to the issue of climate change, the preponderance of evidence is clearly on the side of those advocating for a swift and dramatic reduction in greenhouse gas emissions. Are there bits of information which are inconclusive when it comes to the dangers of climate change? Certainly, there are. But the vast bulk of the information, the preponderance of the evidence we now have, points to huge risks ahead.

Energy Bulletin