As I write this, the sky is pouring cats and dogs on D.C., as it has been for the past several days. In fact, it’s record-setting. Elsewhere in the world, there are people frying eggs on the sidewalk where before they might have prepared a delightful salad. But just a few weeks ago D.C. had unusually dry weather. And last winter we suffered through a bizarrely consistent stretch of cold. In short: we’re living through turbulent times.
Inevitably, news stories ask whether each of these unexpected weather events is “caused by global warming.” The question is poorly formed, and, as a result, so are the answers usually given by meteorologists and other experts. The question is bad because it assumes that we have a standard set of weather (that is, a climate) that just keeps happening unless something unusual, such as a volcanic eruption, “causes” a temporary change. When experts explain these expected climatic patterns, they refer to mid-level causes, such as the interaction of prevailing winds, ocean currents, plant life, and land forms (especially mountains).
But behind the winds and currents (etc.) are more fundamental influences: I’m looking at you, global temperature. This the case always and forever, even in the most average year ever recorded. After all: 1) as we learned in science class, heating air or water changes their movement, 2) air and water are connected throughout the globe in one big system, so 3) local weather is always tied to global temperature. (Plus, changes in temperature affect other influences on the weather, for example the distribution and behavior of organisms that affect climate, such as plants in the Amazon.) Thus, whenever the global temperature has changed throughout the eons, the climate has, too.
This brings me back to the question. It’s more enlightening to ask: would this surprising weather have happened without global warming? And the answer is always no. Maybe the weather would have been more pleasant or even more wretched, but it would be different if the global temperature were different. In sum, all weather, every day, is due to global warming.
Moreover, as long as the global temperature is changing, the weather in any one place will be less repetitive. This is why climate scientists predict more variation in weather patterns unless global temperature levels off. Interestingly, the concept of a climate, which is a generalization based on repeated patterns of weather, will thus be slightly less valid.