The scale of carnage that the Great Hurricane of 1900 wreaked upon Galveston was by no means anomalous in the late nineteenth and early twentieth centuries. Immigration, westward expansion, and urbanization brought large populations into floodplains and coastal regions across the United States. These growing agglomerations of poorly planned, densely populated communities had little hardened infrastructure to speak of, and brought large numbers of people into regular contact with extreme climatic events.
Indeed, the list of the worst climate-related disasters in U.S. history, those that claimed a thousand or more American lives, is dominated by events that occurred before 1940. There were hurricanes in 1893, 1893 again, 1899, 1900, and 1928; heat waves in 1896 and 1936; floods in 1862 and 1889; and wildfires in 1871 and 1918. By contrast, since 1940 only three climate disasters have claimed a thousand or more lives: a heat wave in 1980, Hurricane Katrina in 2005, and Hurricane Maria in 2017.
The story is much the same globally. Two climate disasters have claimed a million or more lives, both of them floods in China, in 1887 and 1931. Tropical storms in South Asia claimed multiple hundreds of thousands of lives in 1737, 1839, and 1876. The more recent climate catastrophes with comparable death tolls, such as the cyclone that killed up to half a million people in what is now Bangladesh in 1970, and the typhoon and resulting dam failure that took a similar toll in China in 1975 amid the chaos of the Cultural Revolution, have reliably occurred at the intersection of poverty, dense population, inadequate infrastructure, and failing political institutions. We tend to think of natural disasters as natural. But the thing that determines how disastrous they are is mainly what humans do, not what nature does.
Discussions of weather-related natural disasters in recent years have largely focused on one particular human factor: the consequences of an anthropogenically warming planet. But the heavy concentration of catastrophic disasters prior to the period when climate change began to significantly warm the planet should remind us that the earth’s climate has always been highly variable, extreme, and dangerous. What determines whether hurricanes, floods, heat waves, and wildfires amount to natural disasters or minor nuisances, though, is mostly not the relative intensity or frequency of the natural hazard but rather how many people are in harm’s way and how well protected they are against the climate’s extremes.