A couple years ago I spoke to a former Liberal member of parliament who had played a key role in developing Canada’s climate policy in the 1990s. He related to me that one of the key difficulties of his job was tackling the enormous complexity of the projected climate shift, where warming in one region might coincide with cooling somewhere else. “After all,” he said matter-of-factly, “it’s not global warming; it’s climate change.” Since then I’ve heard this distinction elsewhere, particularly in reference to periods of unusually cold weather, like the last two winters in Europe. Far from mere semantics, to me the use of the term “climate change” rather than the more alarming “global warming” seems like a new wrinkle in the attempt to discredit or diminish the reality of a warming climate. It also fundamentally misunderstands the nature of a climatic shift.
I study the social effects of the Little Ice Age, a period of climatic variability and general cooling that lingered from the fourteenth to the nineteenth centuries. As a result I know there’s some truth to the idea that a climatic shift means different things for different regions. Owing to a specific intersection of environmental and social structures there are places that are more or less vulnerable to the weather patterns typical of a prevailing climatic regime. Moreover during the coldest decades of the Little Ice Age some regions experienced more precipitation and some less; some areas were wracked with storms, while others grew more tranquil. Indeed, some years, even decades were warmer than average, not just for isolated regions but for the world as a whole. Finally, different parts of the world can have different climatic chronologies: China and Japan appear to have been warm when Europe was cold after the fall of Rome, then cooled as Europe experienced unusual warmth in the high medieval period.
All this complexity can, in the right hands, deliberately obscure a very simple reality: climate deals with nothing more than generalized weather. For all its complexity the Little Ice Age cooled the world’s climate for several hundred years, just as the world’s climate is rapidly warming now and will continue to warm for at least the century to come. After all, the winters that chilled Europe in 2010 occurred during one of the warmest years in record. It is important for policymakers to avoid the assumption that every region will experience a climatic shift in similar fashion, but it is even more important that we don’t lose sight of the forest for the trees.