A Drought in Confidence

This past Sunday, a New York Times opinion piece entitled “Global Warming? Not Always” made the claim that “the scientific evidence does not support an argument that human-induced climate change has played any appreciable role in the current California drought.” To support his argument, NOAA climate scientist Martin P. Hoerling writes that droughts of this magnitude are nothing new to Californians — similar, or even more severe, droughts have occurred in California in the 1930s and 1970s, suggesting that the recent dearth of rainfall in California might fit in perfectly with the observed historical precipitation and climate patterns. In turn, Hoerling concludes that we can’t lay claim to the knowledge that the draught is the product of an anthropogenically changed climate; my concern, however, is whether or not the claim to such knowledge should be all that important to us.

In contemporary philosophy, the standard account of knowledge — that is, the criteria that must be met in order to claim we “know” something — is tripartite, consisting in “justified true belief.” In short, we can say we know something if it is a belief about the world that we actually hold, when that belief accurately represents what is the case out there in the world, and that belief is held appropriately or with good reason. So while it might seem that I’ve just said the same thing twice in a row, there are actually important delineations that can be drawn between these three criteria that I won’t go into here. What’s important to us here is that we might take the claim Hoerling makes in his article to assert that in terms of empirical evidence, our claim to knowledge about whether the droughts in California were caused by anthropogenic climate change in some way fails the tripartite test. I’m now going to propose that we shouldn’t care whether or not it does; or, in a somewhat milder sense, that it doesn’t make much difference.

A recent joint publication produced by the National Academy of Sciences and British Royal Society outlines what, according to climate scientists, is our best evidence supporting the notion that humans are in fact changing the climate. The executive summary: we now, maybe more than ever, know we are. Our understanding of physics, climate models, and fingerprinting of climate change patterns has shown us that there is no realistic way that global temperatures and carbon levels could have increased the way they have without human involvement as it’s played out since we’ve industrialized.

The natural processes that have helped bring about the 0.8 degree (C) warming of the atmosphere are complex and multifaceted, such that I think it would be hard for us to deny that they are the same processes aggravating the conditions in California. Warmer weather means a longer growing season, which leads to increased water usage in commercial food production, as well as in the residential sector. While recent research might propose that “recent long-term droughts in western North America cannot definitively be shown to lie outside the very large envelope of natural precipitation variability in this region,” we might be able to make a claim to other important pieces of knowledge: that if global warming trends continue, human life as we know it will have to change dramatically and struggle more and more to respond to droughts like this one, we won’t be able to bring carbon levels back to pre-industrialized levels in any time-scale smaller than that of millennia, and countless species of plants and animals will go extinct. Fortunately, the NAS and Royal Society agree.

We might also make a different kind of claim — that it would, for one reason or another, be morally wrong for all of the above mentioned things to take place, if we can prevent their doing so. There’s also a funny thing about moral propositions: our criteria for saying that we know something to be true morally often differ from those things we claim to know empirically. Moral knowledge, at least in ordinary cases, seems not to request from us the same standards for empirical truth or justification. We might simply say that it would be a grave injustice for people to be marginalized by water shortages or biological diversity to be sacrificed for economic profit because we believe it to be so.

This article was not intended to lay out any kind of formal argument about the conditions we deem necessary to make claims for knowledge, or whether or not moral knowledge is the same kind of knowledge as empirical scientific knowledge. I think it’s obvious that the two should inform one another. “Knowing” whether or not one catastrophic drought was connected to anthropogenic climate change shouldn’t affect our decision to take the actions necessary to move towards a sustainable, resilient future.