Natural Disasters from 1991 to 2021

To investigate the evolution of natural disasters and their impact over the past century, our analysis includes several visualizations that explore the changes in the frequency of natural disasters and death tolls over time. We hypothesize that the frequency of natural disasters and death tolls has increased throughout the years, and that the relative frequency of natural disasters has increased more sharply in the Southern hemisphere than in the Northern hemisphere.

The dataset used in this analysis (titled “All Natural Disasters 1900-2021/EOSDIS”) was obtained from Kaggle, a publicly available data repository. The dataset has 16126 rows and 45 columns, and provides information about natural disasters that occurred worldwide from the year 1900 through 2021. Our analysis focuses on the following variables: Year, Disaster Type, Country, Location (coordinates using Longitude and Latitude)  and Total Deaths. The original dataset only contained geographical coordinates for earthquakes; so to classify the rest of the disasters by hemisphere (i.e., by latitude sign), we joined the Kaggle dataset with a dataset containing the country coordinates from the public data repository on Google Developers. 

Figure 1: Frequency of natural disasters increased throughout the years

In the introduction, we hypothesized that the frequency of natural disasters has increased over the past hundred years. In Figure 1, we corroborated this hypothesis as we see that the annual count of natural disasters follows a positive linear pattern from 1900 to about 1950, after which it increases exponentially before peaking in the early 2000s. The frequency of natural disasters declined significantly after 2005; this suggests the presence of environmental disturbance(s) that began either during or shortly prior to the 1950s, and whose impact began to lessen from 2005-2021, possibly due to mitigating factors like recycling and the widespread adoption of solar power. After conducting some preliminary research, we discovered that ocean temperatures began rising due to global warming by the 1950s, leading to increased flooding around the same time (EPA, 2023).

Understanding the impact of natural disasters on human lives and societies is crucial, as these events can have devastating consequences. To investigate the trends in human fatalities resulting from natural disasters, we analyzed death counts from 1900 to 2021. Figure 2 displays a clear decline in the number of deaths attributed to natural disasters from 1960-2020, despite the corresponding increase in disaster frequency we observed in Figure 1. 

Figure 2: Death tolls decreased over time despite the increase of natural disasters.

To investigate the reason behind the drop in death counts, we must first determine how trends in disaster type have changed over time. Figure 3 displays this distribution from 1900 to 2021. 

Figure 3: Major Natural Disaster Types Consists of Earthquakes, Floods and Storms

Here, we see that about half of all natural disasters from 1900-1950 were earthquakes, which usually have high initial death tolls; but epidemics became more common after 1950, perhaps due to the spread of commercial international air travel. Flooding also became more common after 1950 (which is consistent with the timeline of global warming), but flood-related deaths might have been limited due to modern developments in infrastructure. It is also important to note that any factors leading to more frequent epidemics have coincided with improvements in sanitation and healthcare. This may be why the uptick in epidemics has not led to higher death tolls, but further analysis is required to draw a definite conclusion. 

In the next section, we aim to determine whether disaster counts in the Northern and Southern hemispheres have changed at different rates since ocean temperatures began to rise in the 1950s. Due to differences in land and ocean mass, the two hemispheres exhibit varying climates and weather patterns as well as different geographical characteristics, and therefore, it is possible that they have been differently affected by climate change. 

Figure 4: Frequency of Natural Disasters in the Northern and Southern hemispheres from 1950-60 and from 2010-20

In Figure 4, we see that the frequency of natural disasters in the Northern hemisphere increased by about ten times between 1950-60 and 2010-20. However, the frequency of natural disasters in the Southern hemisphere increased by about twenty times in the same period; from this, we can conclude that climate change has not affected both hemispheres equally. One possible explanation for this is that extreme weather events were already more common in the Southern hemisphere because more of its area is covered by ocean, leading to a sharper increase in climate-related disasters after ocean temperatures began to rise. Other potential contributing factors include differing policy and infrastructure between countries in the two hemispheres.

Nevertheless, the countries with the highest disaster rate are the United States, China, India and the Philippines in no particular order, which are all located in the Northern hemisphere (Figure 5). The high natural disaster frequency found in China, India, and the U.S. may be due to their large mass, comprising a wider variety of climate zones than most other nations. Canada and Russia are much further north, so it is possible that natural disasters common to temperate and tropical regions are not frequent there in spite of their large land mass. The Philippines on the other hand sits within the Pacific Ring of Fire and Pacific Typhoon Belt, which are areas along the Pacific Ocean that have been identified to contain active volcanoes, frequent earthquakes and typhoons. 

In summary, our analysis reveals a complex landscape of evolving disaster patterns. While the frequency of natural disasters has surged since 1950, our society has shown remarkable progress in reducing death counts, particularly during epidemics, floods, and storms. It is also important to note that the Southern hemisphere appears to have been disproportionately affected by climate change in recent years, which suggests the need for tailored strategies in disaster prevention and relief moving forward.