On 23 June 1988, climate change first hit the headlines when NASA climatologist James Hansen testified before the US Senate: “The greenhouse effect has been detected, and it is changing our climate now,” he warned. That was a year of droughts and heat waves in the US, with severe fires in the Amazon and Yellowstone. The Intergovernmental Panel on Climate Change (IPCC) was created. But despite the long public history of this phenomenon—and its even longer scientific history, going back at least a century—two ideas have been slow to take hold. First, climate change is not an environmental problem, but a global one, threatening the habitability and survival of this planet as we know it. Second, it is not a future prediction; as Hansen warned, it is happening now. These two ideas are embodied in one of the most frightening effects of climate change: the increase in natural disasters, which affect people and which are happening today.
Climate change originates from an increase in the terrestrial greenhouse effect caused by human activity, especially the burning of fossil fuels, which releases large amounts of CO2, the main gas responsible, into the atmosphere. For decades, climate models used by scientists have revealed that this global warming, the primary effects of which are an increase in average temperature, melting ice masses and rising sea levels, causes a disruption in the climate system resulting in an increase in extreme weather events. This was warned about in 1990 by the IPCC, which in its first assessment report mentioned how the combination of climate change and high human population densities, especially in developing countries, “are likely to increase the sensitivity to and potential magnitude of natural disasters.”
From the first IPCC models to current disasters
Even then, the flooding of low-lying coasts due to rising sea levels was among the most worrying effects. In 2005, NASA warned of the threat to populated island regions, including New York City. Even with a certain level of uncertainty due to the limitations of the models and their not always congruent results, the agency suggested, based on previous studies, that a warmer, wetter atmosphere with smaller temperature differences between the equator and the poles was setting the stage for an “increased risk of drought and increased intensity of storms, including tropical cyclones with higher wind speeds, a wetter Asian monsoon, and, possibly, more intense mid-latitude storms.” In addition, it added, “an increase in temperature variability will extend the extremes of temperature, both cold and hot.”
Decades after those first modelled predictions—it is worth clarifying that “prediction” in this context does not necessarily refer to a future event, but also to a past or present one that the model simulates—it is now common to hear talk of an increase in natural disasters due to climate change. And there is no doubt that in recent years humanity has suffered great scourges of nature: massive fires in the US and Australia, violent tropical storms, so many Atlantic hurricanes in a single season (2020) that we ran out of letters in the alphabet to name them, severe floods in Europe, record temperatures of 50 °C in the Canadian Pacific, or a snowstorm in Spain like we haven’t seen in half a century, among many other cases. But beyond the fact that these phenomena may attract more media and public attention today, has there really been an increase in these disasters? And if so, can this be attributed to global warming?
In August 2021, the World Meteorological Organization (WMO) published The Atlas of Mortality and Economic Losses from Weather, Climate and Water Extremes, covering the years 1970 to 2019. The conclusion of this work, the most extensive in its field, is that the number of such disasters has increased fivefold over the past half century. More than 11,000 disasters of the types covered— accounting for half of all natural catastrophes of any kind—occurred in the period studied, with just over two million deaths and global losses of $3.64 trillion. The WMO’s comprehensive work also corroborates previous analyses by the United Nations and other organisations that have also found an increase in natural disasters due to extreme weather events in recent decades.
Worryingly, more than 91% of deaths occurred in developing countries, with droughts, storms, floods and extreme temperatures being the deadliest disasters. And beyond the deaths, it is also the poor nations that are most affected by the large migrations provoked by these catastrophes.
More accurate models to help find a correlation
According to WMO Secretary General Petteri Taalas, “the number of extreme weather, climate and water-related events is increasing and will become more frequent and severe in many parts of the world as a result of climate change.” But far from assuming a blanket, default culpability of climate change for all these catastrophes, since 2004—when the first of these studies was published—there has been a proliferation of research assessing the possible attribution of specific natural disasters to the effects of climate change (to some degree), using improved models that compare outcomes in the presence or absence of climate change. As Scientific American published in 2018, this is one of the most rapidly expanding sub-fields of climate science.
The WMO reviews the scientific studies related to different specific disasters, which are published each year in the bulletin of the American Meteorological Society and which use current scientific tools to assess the impact of climate change on extreme events. Between 2015 and 2017, 62 of the 77 recorded events show a significant human influence. In general, the cause-effect link between climate change and these events is strong for heat waves and extreme temperatures, as well as for some large cyclones and heavy rainfall events, but less so for droughts, which are also affected by variable natural phenomena such as El Niño-Southern Oscillation. However, models have detailed specific cases, such as the influence of anthropogenic warming of the Indian Ocean on the 2016-2017 East African drought.
As if this were not enough, another category must be added to weather- or water-related disasters, namely geological catastrophes. When geophysicist Bill McGuire published a book in 2012 warning that climate change could cause volcanic eruptions, earthquakes and tsunamis, some commentators called his prediction alarmist. However, McGuire’s thesis was supported by scientific studies, which have subsequently been joined by additional research showing how the disappearance of land ice, large rainfall events or even low pressures associated with cyclones can cause small disturbances in areas of the earth’s crust that, if already in a critical state, could be the final trigger for earthquakes or volcanic eruptions. As McGuire quotes another colleague of his, “if a fault is primed and ready to rupture, all that is needed is the pressure of a handshake to set if off.”
Improvement of models and greater cooperation
In the face of all this, how to combat this growing problem? Of course, fighting climate change by tackling the root cause—primarily, but not only, the use of fossil fuels—is an inescapable duty. But the concrete effects in the form of natural disasters have their own approaches. And while it is often not possible to avoid or contain nature’s onslaught, we can at least be better prepared. According to the WMO Atlas, even with natural disasters five times more frequent than half a century ago, deaths have been reduced by almost a third, from more than 50,000 in the 1970s to less than 20,000 in 2010, thanks to improved early warning and disaster management.
But on the flip side of the coin, the same cannot be said for economic losses, which have increased sevenfold from 1970 to 2019. The greatest toll of these losses were caused by the major cyclones; in fact, three hurricanes in the same year—2017—accounted for more than a third of the economic damage inflicted by the 10 largest natural climate disasters of the last half-century.
Thus there is a great need for improvement. But even current models attributing extreme events to climate change are not good at predicting future disasters; some of these catastrophes surprise even scientists. Global climate models do not have sufficient resolution to predict regional or local events, unlike weather models, which operate on a fine scale and in the short term. According to ClimateWire, the idea is circulating among scientists of building climate supermodels capable of predicting extreme events locally and years in advance, which would require the use of supercomputers, but at the moment this is more of a dream than a concrete plan
Therefore, the current room for improvement lies mostly in disaster preparedness and management. According to the WMO, only half of the 193 member countries have early warning systems for multiple natural disasters. Meteorological and hydrological monitoring networks are particularly weak in Africa, parts of Latin America and in island states in the Pacific and the Caribbean. In 2015, the United Nations launched the Sendai Framework for Disaster Risk Reduction (2015-2030), with the objectives of advancing understanding of disaster risk, its management, investment in preparedness and prevention, and the response to its impacts.
However, the director of the UN Office for Disaster Risk Reduction (UNDRR) herself, Mami Mizutori, notes a “failure to reduce disaster losses” in accordance with the Sendai Framework, urging countries to increase international cooperation and investment in adaptation to a climate change that, without question, casts doubt on whether we can continue to talk about entirely “natural” disasters.