Did climate change cause these hurricanes?

Tropical cyclones, climatology, and capitalism

In the past few weeks, the damage resulting from Hurricane Harvey and Hurricane Irma have been dominating headlines.

Harvey was the first, moving along the south Caribbean before taking a turn by the Yucatan Peninsula and then becoming a Category 4 before making landfall in southern Texas. It was the first hurricane to do so since Wilma in 2005. What came after was the absolute decimation compounded by what is best described as solidarity interlaced with a deep lack of empathy. As record-breaking levels of hurricane rains flooded Houston, local residents and helpers from around the country and other nations came by to mobilize whatever assistance they could. At the same time, some of the ugliest parts of an intensely individualistic, colonialist, and capitalist society reared its head, as basic goods like water and non-perishable foods were heavily marked-up in price to generate a profit from this disaster. Poor and racialized people were largely left to fend for themselves; the government intentionally took action to keep undocumented people from escaping the area, large churches refused to open their doors as shelter, and survivors—especially people of colour—who were attempting to gather supplies were branded as “looters” by people who had comfortably escaped. Harvey’s overall damage is thought to be somewhere between $70 to $200 billion, with around $35 billion alone in flooding damages. To top it all off, the Associated Press reports that the majority of these ghastly prices are to be footed by uninsured homeowners who have no actual ways to pay.

Irma came next, a powerful Category 5 hurricane that formed through tropical waves by Cape Verde, a type of hurricane known to be particularly damaging if it doesn’t prematurely die out. While Florida was spared from the same level of damage that Houston and southern Texas faced with Harvey, Irma’s destruction came with its effects on the Caribbean nations and colonies, Antigua and Barbuda. Barbuda was essentially almost wiped off the map, with 95% of its buildings and infrastructure completely destroyed. The islands of Saint Martin and Saint Barthelemy experienced a similar level of extreme destruction, and the British and U.S. Virgin Islands were decimated. Waves by Puerto Rico reached about 9 meters in height. Irma hit Cuba as a Category 5 storm and even with the quick mobilization against the hurricane a week prior, about $2 billion in damages have been reported. The Florida Keys and south Florida were hit heavily, with massive infrastructure damages, but by the time the storm reached Tampa it had been downgraded to a Category 1 storm. At 929 millibars of landfall pressure, Irma quickly gained a reputation as one of the strongest hurricanes in this part of the Atlantic.

Two powerful hurricanes essentially a week apart—this seems unprecedented. This is— notwithstanding the wildfires blazing across parts of the west, and the far more brutally destructive South Asian floods happening concurrently that have killed upwards of 1200 people. What is going on here? The quickest logical conclusion would be to connect this with climate change. So, how far does the causal relationship between climate change and these destructive events go?

To attempt to forge a connection between climate change and hurricanes, we need to first understand how exactly hurricanes develop and work. Hurricanes are a subset of the generalized term “tropical cyclones,” which also includes typhoons, and the word “hurricane” explicitly refers to a type of tropical cycle that is formed around the Caribbean Sea and the Pacific just directly west of Central America. The name gives a hint about their origins; these cyclones form around the warm tropical water by the equator. These parts of the ocean produce warm, humid air; westerly winds from Africa help evaporate warm ocean surface water, and let the resulting hot air rise until it cools down into colder water droplets, producing large cumulonimbus “storm clouds.” Large groups of these typically give rise to the well-known rainy activity at the tropics.

From here, climate scientists classify a 4-step cyclone progression. A “tropical disturbance” is just an especially large patch of sustained thunderstorm activity over the ocean that keeps itself intact over a day. These disturbances typically begin to move westward, forming “tropical waves.” Next is a “tropical depression” where we see the first signs of cyclonic activity; if the water is warm enough and the winds are just right, the rising-falling air cycles can give rise to low-pressure centers in the cumulonimbus cloud column, causing strong winds and the mass to start rotating. A “tropical storm” is when the climatologists start ringing their alarm bells for possible hurricane activity. They describe these as cases when the central air pressure drops enough to allow well-defined cyclic activity with very fast wind speeds within the storm. Finally, if this tropical storm passes over a nice patch of warm water, things really get intense as the central pressure drops even further, forming the characteristic “eye” and rounded shape of a hurricane. As we can see, warmth plays a particularly important part in this cascade.

So then what can conclusively be said about hurricanes and climate change? Did climate change cause these hurricanes, or merely intensify them? Can we blame climate change as the principal causal action? Firstly, climate change “causing” any particular effect is a misnomer. At best, it can influence existing disasters. However, climate scientist Michael Mann explains how climate change has intensified the destruction caused by these hurricanes. The rise in sea levels by about 15cm notably made storm surges—and subsequent flooding—much worse. Warmer sea temperatures caused by climate change directly influenced the greater moisture content of the air, thus intensifying rainfall and the overall ferocity of the hurricane. Finally, based on Mann’s personal speculations, Houston faced a particularly terrible onslaught because Harvey “stalled” by the coast for a bit. This was due to generally weak prevailing winds, which is an occurrence known to be influenced by anthropogenic climate change. But will climate change actually increase the frequency of these hurricanes? Unfortunately the research on this is mixed, so the jury is still out on this particular question. However, what we do know is that any future hurricanes we get will be very destructive.

The reality is that climate change is part of a bigger causal picture, a lumbering beast behind the scenes that prods at these events and intensifies them. But, by squarely placing the blame on climate change, we can’t forget the agency that we as humans have in making our own protection and adaptation decisions. Mitigation of the effects of hurricanes, of natural disasters in general, and of climate change rest on safeguarded policy and collective action, particularly against an unsustainable capitalist system. Some of the worst-hit victims of climate change influenced disasters will be the poorest, most colonized, and racialized populations that are also heavily exploited by capitalism. The ultimate desire for profit and an abstract sense of growth at the expense of the environment and collective solidarity is precisely the same mentality that has led to policy decisions in the most powerful nation on the planet that deliberately gut climate research and lead astray public opinion for the purposes of personal gain. Our responses to hurricanes are dependent on the need to move beyond this. While Cuba’s local committees quickly and successfully mobilized evacuations and shelters and later had enough medical personnel on hand to tend to other island nations destroyed by Irma, undocumented people in Houston were uncertain of whether or not shelters would even accept them without asking to look at their papers.

It’s time to understand that our responses to hurricanes must be hand-in-hand with our responses to climate change, and these must be responses that ultimately re-center the environment and the people who live in it.