Little Evidence for Link between Natural Disasters and Global Warming

A new report on extreme weather in 2020 shows how socio-economic studies of natural disasters have been used to buttress the popular but mistaken belief that global warming causes weather extremes. Two international agencies, UNDRR (the UN Office for Disaster Risk Reduction) – in conjunction with CRED (the Centre for Research on the Epidemiology of Disasters) – and IFRC (the International Red Cross), both issued reports in 2020 claiming that climate-related disasters are currently escalating.

However, as the two reports themselves reveal, such claims are manifestly wrong. This can be seen in the following figure, originally included in the UNDRR-CRED’s report but since withdrawn, showing the annual number of climate-related disasters from 2000 through 2020. The disasters are those in the yellow climatological (droughts, glacial lake outbursts and wildfires), green meteorological (storms, extreme temperatures and fog), and blue hydrological (floods, landslides and wave action) categories.

The UNDRR-CRED report draws a strong link between global warming and extreme weather events, citing a “staggering rise in climate-related disasters over the last twenty years.” But, as shown in the figure above, the total number of climate-related disasters in fact exhibits a distinctly declining trend (in red) since 2000, falling by 11% over the last 21 years. This completely contradicts the claims in two different sections of the report that the annual number of disasters since 2000 has either risen significantly from before or been “relatively stable.”

Another blatant inconsistency in the UNDRR-CRED report, an inconsistency that bolsters its false claim of a rising disaster rate, is a comparison between the period from 2000 to 2019 and the preceding 20 years from 1980 to 1999. The report contends that the earlier 20 years saw only 4,212 disasters, compared with 7,348 during the later period.       

However, the University of Colorado’s Roger Pielke Jr., who studies natural disasters, says that the report’s numbers are flawed. As CRED has repeatedly acknowledged, data from 20th-century disasters are unreliable because disasters were reported differently before the Internet existed. Climate writer Paul Homewood has noted a sudden jump in the annual number of disasters listed in CRED’s EM-DAT (Emergency Events Database) after 1998, which the agency itself attributes to increased disaster reporting in the Internet era. So its claim that the number of disasters over 20 years jumped from 4,212 to 7,348 is meaningless.

The IFRC report reaches the same erroneous conclusions as the CRED-UNDRR report – not surprisingly, since they are both based on CRED’s EM-DAT. As seen in the next figure, which is the same as the Red Cross report’s Figure 1.1, climate- and weather-related disasters since 2000 have declined by approximately the same 11% noted above. The report’s misleading assertion that such disasters have risen almost 35% since the 1990s relies on the same failure to account for a major increase in disaster reporting since 1998 due to the arrival of the Internet.

That natural disasters are in fact diminishing over time is reinforced by data on the associated loss of life. The figure below illustrates the annual global number of deaths from natural disasters, including weather extremes, corrected for population increase over time and averaged by decade from 1900 to 2015.

Because the data is compiled from the same EM-DAT database, the annual number of deaths shows an uptick from the 1990s to the 2000s. Yet it’s abundantly clear that disaster-related deaths have been dwindling since the 1920s. However, this is due as much to improvements in planning and engineering to safeguard structures, and to early warning systems that allow evacuation of threatened communities, as it is to diminishing numbers of natural disasters.

Economic loss studies of natural disasters have been quick to blame human-caused climate change for the apparently increasing frequency and intensity of weather-related events. But once the losses are corrected for population gain and the ever-increasing value of property in harm’s way, there’s very little evidence to support any connection between natural disasters and global warming.

According to numerous analyses by Pielke, the frequency and intensity of the phenomena causing financial losses show no detectable trend to date. Climate-related losses themselves are actually declining as a percentage of global gross domestic product. Another research study, based on the NatCatSERVICE database of reinsurance giant Munich Re, has concluded that both human and economic vulnerability to climate-related disasters exhibit a decreasing trend, and that average disaster mortality has dropped by a sizable 6.5 times from 1980–1989 to 2007–2016.

The IPCC (Intergovernmental Panel on Climate Change), whose assessment reports serve as the voice of authority for climate science, endorsed these findings in a 2014 report on the impacts of climate change. But most of the political world and the mainstream media cling to the erroneous notion that extreme weather is triggered by global warming and becoming more frequent, despite a lack of scientific evidence for either assertion.

Next: Is Recent Record Cold Just La Niña, or the Onset of Global Cooling?