The History of Pandemics
Pan·dem·ic /panˈdemik/ (of a disease) prevalent over a whole country or the world.
As humans have spread across the world, so have infectious diseases. Even in this modern era, outbreaks are nearly constant, though not every outbreak reaches pandemic level as COVID-19 has.
Today’s visualization outlines some of history’s most deadly pandemics, from the Antonine Plague to the current COVID-19 event.
A Timeline of Historical Pandemics
Disease and illnesses have plagued humanity since the earliest days, our mortal flaw. However, it was not until the marked shift to agrarian communities that the scale and spread of these diseases increased dramatically.
Widespread trade created new opportunities for human and animal interactions that sped up such epidemics. Malaria, tuberculosis, leprosy, influenza, smallpox, and others first appeared during these early years.
The more civilized humans became – with larger cities, more exotic trade routes, and increased contact with different populations of people, animals, and ecosystems – the more likely pandemics would occur.
Here are some of the major pandemics that have occurred over time:
|Name||Time period||Type / Pre-human host||Death toll|
|Antonine Plague||165-180||Believed to be either smallpox or measles||5M|
|Japanese smallpox epidemic||735-737||Variola major virus||1M|
|Plague of Justinian||541-542||Yersinia pestis bacteria / Rats, fleas||30-50M|
|Black Death||1347-1351||Yersinia pestis bacteria / Rats, fleas||200M|
|New World Smallpox Outbreak||1520 – onwards||Variola major virus||56M|
|Great Plague of London||1665||Yersinia pestis bacteria / Rats, fleas||100,000|
|Italian plague||1629-1631||Yersinia pestis bacteria / Rats, fleas||1M|
|Cholera Pandemics 1-6||1817-1923||V. cholerae bacteria||1M+|
|Third Plague||1885||Yersinia pestis bacteria / Rats, fleas||12M (China and India)|
|Yellow Fever||Late 1800s||Virus / Mosquitoes||100,000-150,000 (U.S.)|
|Russian Flu||1889-1890||Believed to be H2N2 (avian origin)||1M|
|Spanish Flu||1918-1919||H1N1 virus / Pigs||40-50M|
|Asian Flu||1957-1958||H2N2 virus||1.1M|
|Hong Kong Flu||1968-1970||H3N2 virus||1M|
|HIV/AIDS||1981-present||Virus / Chimpanzees||25-35M|
|Swine Flu||2009-2010||H1N1 virus / Pigs||200,000|
|SARS||2002-2003||Coronavirus / Bats, Civets||770|
|Ebola||2014-2016||Ebolavirus / Wild animals||11,000|
|MERS||2015-Present||Coronavirus / Bats, camels||850|
|COVID-19||2019-Present||Coronavirus – Unknown (possibly pangolins)||848K (Johns Hopkins University estimate as of 10:28am PT, Aug 31, 2020)|
Despite the persistence of disease and pandemics throughout history, there’s one consistent trend over time – a gradual reduction in the death rate. Healthcare improvements and understanding the factors that incubate pandemics have been powerful tools in mitigating their impact.
Wrath of the Gods
In many ancient societies, people believed that spirits and gods inflicted disease and destruction upon those that deserved their wrath. This unscientific perception often led to disastrous responses that resulted in the deaths of thousands, if not millions.
In the case of Justinian’s plague, the Byzantine historian Procopius of Caesarea traced the origins of the plague (the Yersinia pestis bacteria) to China and northeast India, via land and sea trade routes to Egypt where it entered the Byzantine Empire through Mediterranean ports.
Despite his apparent knowledge of the role geography and trade played in this spread, Procopius laid blame for the outbreak on the Emperor Justinian, declaring him to be either a devil, or invoking God’s punishment for his evil ways. Some historians found that this event could have dashed Emperor Justinian’s efforts to reunite the Western and Eastern remnants of the Roman Empire, and marked the beginning of the Dark Ages.
Luckily, humanity’s understanding of the causes of disease has improved, and this is resulting in a drastic improvement in the response to modern pandemics, albeit slow and incomplete.
The practice of quarantine began during the 14th century, in an effort to protect coastal cities from plague epidemics. Cautious port authorities required ships arriving in Venice from infected ports to sit at anchor for 40 days before landing — the origin of the word quarantine from the Italian “quaranta giorni”, or 40 days.
One of the first instances of relying on geography and statistical analysis was in mid-19th century London, during a cholera outbreak. In 1854, Dr. John Snow came to the conclusion that cholera was spreading via tainted water and decided to display neighborhood mortality data directly on a map. This method revealed a cluster of cases around a specific pump from which people were drawing their water from.
While the interactions created through trade and urban life play a pivotal role, it is also the virulent nature of particular diseases that indicate the trajectory of a pandemic.
Scientists use a basic measure to track the infectiousness of a disease called the reproduction number — also known as R0 or “R naught.” This number tells us how many susceptible people, on average, each sick person will in turn infect.
Measles tops the list, being the most contagious with a R0 range of 12-18. This means a single person can infect, on average, 12 to 18 people in an unvaccinated population.
While measles may be the most virulent, vaccination efforts and herd immunity can curb its spread. The more people are immune to a disease, the less likely it is to proliferate, making vaccinations critical to prevent the resurgence of known and treatable diseases.
It’s hard to calculate and forecast the true impact of COVID-19, as the outbreak is still ongoing and researchers are still learning about this new form of coronavirus.
Urbanization and the Spread of Disease
We arrive at where we began, with rising global connections and interactions as a driving force behind pandemics. From small hunting and gathering tribes to the metropolis, humanity’s reliance on one another has also sparked opportunities for disease to spread.
Urbanization in the developing world is bringing more and more rural residents into denser neighborhoods, while population increases are putting greater pressure on the environment. At the same time, passenger air traffic nearly doubled in the past decade. These macro trends are having a profound impact on the spread of infectious disease.
As organizations and governments around the world ask for citizens to practice social distancing to help reduce the rate of infection, the digital world is allowing people to maintain connections and commerce like never before.
Editor’s Note: The COVID-19 pandemic is in its early stages and it is obviously impossible to predict its future impact. This post and infographic are meant to provide historical context, and we will continue to update it as time goes on to maintain its accuracy.
Update (March 15, 2020): We’ve adjusted the death toll for COVID-19, and will continue to update on a regular basis.
Visualized: A Global Risk Assessment of 2021 And Beyond
Which risks are top of mind in 2021? We visualize the World Economic Forum’s risk assessment for top global risks by impact and livelihood.
Visualized: A Global Risk Assessment of 2021 And Beyond
Risk is all around us. After the events of 2020, it’s not surprising that the level and variety of risks we face have become more pronounced than ever.
Every year, the World Economic Forum analyzes the top risks in the world in its Global Risks Report. Risks were identified based on 800+ responses of surveyed leaders across various levels of expertise, organizations, and regional distribution.
Which risks are top of mind in 2021?
The World’s Top Risks by Likelihood and Impact
According to WEF’s risk assessment methodology, all the global risks in 2021 fall into the following broad categories:
- 🔵 Economic
- 🟢 Environmental
- 🟠 Geopolitical
- 🔴 Societal
- 🟣 Technological
It goes without saying that infectious diseases have now become one of the top societal risks on both metrics of likelihood and impact.
That said, environmental risks continue to dominate the leaderboard, accounting for five of the top 10 risks by impact, especially when it comes to climate action failure.
Several countries are off-track in meeting emissions goals set by the Paris Climate Agreement in 2015, while the pandemic has also delayed progress in the shift towards a carbon-neutral economy. Meanwhile, biodiversity loss is occurring at unprecedented rates.
|Rank||Top Risks by Likelihood||Top Risks by Impact|
|#1||🟢Extreme weather||🔴Infectious diseases|
|#2||🟢Climate action failure||🟢Climate action failure|
|#3||🟢Human environmental damage||🟠Weapons of mass destruction|
|#4||🔴Infectious diseases||🟢Biodiversity loss|
|#5||🟢Biodiversity loss||🟢Natural resource crises|
|#6||🟣Digital power concentration||🟢Human environmental damage|
|#7||🟣Digital inequality||🔴Livelihood crises|
|#8||🟠Interstate relations fracture||🟢Extreme weather|
|#9||🟣Cybersecurity failure||🔵Debt crises|
|#10||🔴Livelihood crises||🟣IT Infrastructure breakdown|
As for other risks, the prospect of weapons of mass destruction ranks in third place for potential impact. In the global arms race, a single misstep would trigger severe consequences on civil and political stability.
New Risks in 2021
While many of the risks included in the Global Risks Report 2021 are familiar to those who have read the editions of years past, there are a flurry of new entries to the list this year.
Here are some of the most interesting ones in the risk assessment, sorted by category:
COVID-19 has resulted in a myriad of knock-on societal risks, from youth disillusionment and mental health deterioration to livelihood crises. The first two risks in particular go hand-in-hand, as “pandemials” (youth aged 15-24) are staring down a turbulent future. This generation is more likely to report high distress from disrupted educational and economic prospects.
At the same time, as countries prepare for widespread immunization against COVID-19, another related societal risk is the backlash against science. The WEF identifies vaccines and immunization as subjects susceptible to disinformation and denial of scientific evidence.
As monetary stimulus was kicked into high gear to prop up markets and support many closed businesses and quarantined families, the economic outlook seems more fragile than ever. Debt-to-GDP ratios continue to rise across advanced economies—if GDP growth stagnates for too long, a potential debt crisis could see many businesses and major nations default on their debt.
With greater stress accumulating on a range of major industries such as travel and hospitality, the economy risks a build-up of “zombie” firms that drag down overall productivity. Despite this, market valuations and asset prices continue to rise, with equity markets rewarding investors betting on a swift recovery so far.
Last but not least, COVID-19 has raised the alert on various technological risks. Despite the accelerated shift towards remote work and digitalization of entire industries, the reality is that digital inequality leaves those with lower digital literacy behind—worsening existing inequalities.
Big Tech is also bloating even further, growing its digital power concentration. The market share some companies hold in their respective sectors, such as Amazon in online retail, threatens to erode the agency of other players.
Assessing the Top 10 Risks On the Horizon
Back in mid-2020, the WEF attempted to quantify the biggest risks over an 18-month period, with a prolonged economic recession emerging on top.
In this report’s risk assessment, global risks are further classified by how soon their resulting threats are expected to occur. Weapons of mass destruction remain the top risk, though on a much longer scale of up to 10 years in the future.
|#1||🟠Weapons of mass destruction||62.7||Long-term (5-10 years)|
|#2||🔴Infectious diseases||58||Short-term risks (0-2 years)|
|#3||🔴Livelihood crises||55.1||Short-term risks (0-2 years)|
|#4||🔵Asset bubble burst||53.3||Medium-term risks (3-5 years)|
|#5||🟣 IT infrastructure breakdown||53.3||Medium-term risks (3-5 years)|
|#6||🔵Price instability||52.9||Medium-term risks (3-5 years)|
|#7||🟢Extreme weather events||52.7||Short-term risks (0-2 years)|
|#8||🔵Commodity shocks||52.7||Medium-term risks (3-5 years)|
|#9||🔵Debt crises||52.3||Medium-term risks (3-5 years)|
|#10||🟠State collapse||51.8||Long-term (5-10 years)|
Through this perspective, COVID-19 (and its variants) remains high in the next two years as the world scrambles to return to normal.
It’s also clear that more economic risks are taking center stage, from an asset bubble burst to price instability that could have a profound effect over the next five years.
Visualizing Countries by Share of Earth’s Surface
There are 510 million km² of area on the Earth, but less than 30% of this is land. Here’s the share countries make up of the Earth’s surface.
Visualizing Countries by Share of Earth’s Surface
There are over 510 million square kilometers of area on the surface of Earth, but less than 30% of this is covered by land. The rest is water, in the form of vast oceans.
Today’s visualization uses data primarily from the United Nations Statistics Division (UNSD) to rank the world’s countries by their share of Earth’s surface.
Breakdown of Countries Share of Earth’s Surface
The largest countries by surface area are Russia (3.35%), Canada (1.96%), and China (1.88%).
Together they occupy roughly 7.2% of Earth’s surface. Russia is so big that even if we divided the country between its Asian and European sections, those new regions would still be the largest in their respective continents.
|Country / Dependency||Total in km² (mi²)||Percentage of Earth's Surface|
|United States||9,525,067 (3,677,649)||1.867%|
|D.R. Congo||2,344,858 (905,355)||0.460%|
|Greenland (Denmark)||2,166,086 (836,330)||0.425%|
|Saudi Arabia||2,149,690 (830,000)||0.421%|
|South Africa||1,221,037 (471,445)||0.239%|
|South Sudan||644,329 (248,777)||0.126%|
|Central African Republic||622,984 (240,535)||0.122%|
|Papua New Guinea||462,840 (178,700)||0.091%|
|Republic of the Congo||342,000 (132,000)||0.067%|
|Ivory Coast||322,463 (124,504)||0.063%|
|Burkina Faso||274,222 (105,878)||0.054%|
|New Zealand||270,467 (104,428)||0.053%|
|United Kingdom||242,495 (93,628)||0.048%|
|North Korea||120,540 (46,540)||0.024%|
|South Korea||100,210 (38,690)||0.020%|
|United Arab Emirates||83,600 (32,300)||0.016%|
|Czech Republic||78,865 (30,450)||0.015%|
|Sierra Leone||71,740 (27,700)||0.014%|
|Sri Lanka||65,610 (25,330)||0.013%|
|Bosnia and Herzegovina||51,209 (19,772)||0.010%|
|Costa Rica||51,100 (19,700)||0.010%|
|Dominican Republic||48,671 (18,792)||0.010%|
|Solomon Islands||28,896 (11,157)||0.006%|
|Equatorial Guinea||28,051 (10,831)||0.005%|
|North Macedonia||25,713 (9,928)||0.005%|
|El Salvador||21,041 (8,124)||0.004%|
|East Timor||14,919 (5,760)||0.003%|
|The Bahamas||13,943 (5,383)||0.003%|
|The Gambia||11,295 (4,361)||0.002%|
|State of Palestine||6,020 (2,320)||0.001%|
|Trinidad and Tobago||5,130 (1,980)||0.001%|
|Cape Verde||4,033 (1,557)||0.001%|
|São Tomé and Príncipe||964 (372)||0.000%|
|Federated States of Micronesia||702 (271)||0.000%|
|Saint Lucia||616 (238)||0.000%|
|Antigua and Barbuda||442 (171)||0.000%|
|Saint Vincent and the Grenadines||389 (150)||0.000%|
|Saint Kitts and Nevis||261 (101)||0.000%|
|Marshall Islands||181 (70)||0.000%|
|San Marino||61 (24)||0.000%|
|Vatican City||0.49 (0.19)||0.000%|
Antarctica, although not a country, covers the second largest amount of land overall at 2.75%. Meanwhile, the other nations that surpass the 1% mark for surface area include the United States (1.87%), Brazil (1.67%), and Australia (1.51%).
The remaining 195 countries and regions below 1%, combined, account for the other half of Earth’s land surface. Among the world’s smallest countries are the island nations of the Caribbean and the South Pacific Ocean. However, the tiniest of the tiny are Vatican City and Monaco, which combine for a total area of just 2.51 km².
The remaining 70% of Earth’s surface is water: 27% territorial waters and 43% international waters or areas beyond national jurisdiction.
Areas Beyond National Jurisdiction
In the past, nations adhered to the freedom-of-the-seas doctrine, a 17th century principle that limited jurisdiction over the oceans to a narrow area along a nation’s coastline. The rest of the seas did not belong to any nation and were free for countries to travel and exploit.
This situation lasted into the 20th century, but by mid-century there was an effort to extend national claims as competition for offshore resources became increasingly fierce and ocean pollution became an issue.
In 1982, the United Nations adopted the Law of the Sea Convention which extended international law over the extra-territorial waters. The convention established freedom-of-navigation rights and set territorial sea boundaries 12 miles (19 km) offshore with exclusive economic zones up to 200 miles (322 km) offshore, extending a country’s influence over maritime resources.
Does Size Matter?
The size of countries is the outcome of politics, economics, history, and geography. Put simply, borders can change over time.
In 1946, there were 76 independent countries in the world, and today there are 195. There are forces that push together or pull apart landscapes over time. While physical geography plays a role in the identity of nations, Sheikh Zayed bin Sultan Al Nahyan, the former ruler of UAE, a tiny Gulf nation, put it best:
“A country is not measured by the size of its area on the map. A country is truly measured by its heritage and culture.”
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