A Valeriepieris circle (// VAL-ə-ree-PY-rəs) is a figure drawn on the Earth's surface such that the majority of the human population lives within its interior. The concept was originally popularized by a map posted on Reddit in 2013, made by an American ESL teacher named Ken Myers, whose username on the site gave the figure its name.[better source needed] Myers's original circle covers only about 10% of the Earth's total surface area, with a radius of around 4,000 kilometers (2,500 miles), centered in the South China Sea and covers more than half of Asia, including some of the world's most populous countries. The map became a popular meme, and was featured in numerous internet media outlets.
Myers's original map uses the Winkel tripel projection, which means that his circle, not having been adjusted to the projection, does not correspond to a circle on the surface of a sphere.
In 2015, Singaporean professor Danny Quah verified Myers's original claim, as well as presenting a new, considerably smaller circle centered on the township of Mong Khet in Myanmar, with a radius of 3,300 kilometers (2,050 mi). In fact, Quah claimed this circle to be the smallest one possible, having been produced from more rigorous calculations and updated data, as well as being a proper circle on the Earth's surface.
In 2022, Myers's original circle was again tested by Riaz Shah, a professor at Hult International Business School. Shah used recently published data from the United Nations' World Population Prospects to estimate that 4.2 billion people lived inside the circle as of 2022, out of a total human population of 8 billion. Mapmaker Alasdair Rae proposed The Yuxi Circle, after reviewing 1,500 circles (148 of which had 4 billion or more inhabitants), claiming that the city of Yuxi in Yunnan province, China has the largest population living within a 4,000 km radius: 4.32 billion (55% of the world population at the moment).
The smaller Valeriepieris circle is densely populated, containing almost all of China, India, Borneo and the Philippines; large parts of Indonesia, Pakistan and Korea; and the entirety of Taiwan, Nepal, Bangladesh, Sri Lanka and Mainland Southeast Asia.
Myers's idea has been formalized and a Valeriepieris circle can be defined for any spatial area, like a single country. These generalized circles can be used for studying population changes over time, dimensional reduction and measuring population centralization.
The small radius of the Valeriepieris circle results from the geographical proximity of several of the world's largest population concentrations. Arthur attributes its unusually small size specifically to the very large populations of northern India, southern China and Southeast Asia, which lie close enough together to comprise half of the world's population. The circle's center consequently lies approximately between the major population concentrations of India and China.
The concentration has deep historical roots and substantially predates modern population growth. The development of agriculture was associated with major population growth in Asia, whose population probably exceeded 100 million by the beginning of the Common Era. Historical estimates indicate that Asia accounted for approximately 66% of the world's population in 1000, 62% in 1500 and 65% in 1820. China and India alone accounted for about half of the world's population in both 1000 and 1500. Thus, much of the modern concentration represented by the circle developed from population centers that had already been exceptionally large for centuries.
The physical geography of monsoon Asia helped support these populations. The Asian monsoon supplies much of the moisture used by agriculture across the region, while major rivers originating in and around the Tibetan Plateau carry water to extensive fertile floodplains. Monsoon rainfall, temperature and river systems have consequently shaped the distribution of rice, millet and wheat cultivation across Asia. These environmental conditions supported some of the world's oldest and historically most productive agricultural systems.
Rice agriculture was particularly important in many of the regions within the circle, although it was not the only basis of their agricultural systems. Archaeological research describes rice as having supported dense populations and state societies across eastern, southern and southeastern Asia for much of recorded history and later prehistory. Archaeological evidence places important early centers of cultivated rice in the middle and lower Yangtze valleys, from which rice agriculture subsequently spread more widely through East, South and Southeast Asia. Other parts of the region relied heavily on crops such as wheat and millet, making the broader combination of monsoon rainfall, river valleys, fertile plains and intensive agriculture more significant than rice cultivation alone.
Modern demographic change increased the size of these already-established populations. During the twentieth century, the Indian subcontinent and Southeast Asia experienced prolonged demographic transitions accompanied by substantial population growth, while China subsequently underwent a more rapid transition that limited later growth. The present-day Valeriepieris circle therefore reflects both modern demographic expansion and a much older geographical concentration of population in the agricultural regions of South, East and Southeast Asia.
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- Media related to Valeriepieris circle at Wikimedia Commons