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Homo sapiens, like every other organism on our planet, has its own niche. A comfortable temperature for humans ranges from 17°C to 24°C (62.6 to 75.2 °F). Within that temperature span, the ideal, especially for young and older people, is 22 to 23 °C (72 to 73°F), but it could be some degrees lower with high humidity and some degrees higher with low humidity. Mild heat strain starts at about 23°C (73.4°F) with high humidity or about 27°C (80.6°F) with low humidity. At medium humidity, heat strain is considered to be severe at 32°C (89.6°F), very severe at 36°C (96.8°F), and extreme at temperatures higher than 40°C (104°F), which can be lethal. Of course, people bear much hotter or colder weather, but there is a limit. Almost everybody finds city temperatures above 30 °C (86 °F) unacceptably hot. And people feel that days which don’t get above 17 °C (63 °F) are unpleasantly cold, at least for a leisure that’s not focussed on winter sports. Both cold and hot temperatures may have short-term effects on heart rate and blood pressure. Some studies even show that people who grew up in regions with more mild temperatures closer to 22 °C (71.6°F) scored higher on personality factors linked to socialization and stability (agreeableness, emotional stability, conscientiousness) and personal growth and plasticity (extraversion and openness to experience).

Regarding the climatic zones, the most significant number of days with comfortable temperatures for human life is found mainly in the subtropics. But climatic conditions comfortable for the human body are not the only condition for the progress of human societies. Historically, the emergence of progressive societies is confined to areas with climatic conditions that are comfortable not only for human habitation but also for the growth and habitat of economically important plants and animals. Therefore, I would say that the article below refers not only to the niche of Homo sapiens alone but rather to the niche of a community of humans, domesticated animals, and plants as a kind of “super-organism,” which, for example, can be called Homo agricultures.

Dutch research ecologist Marten Scheffer and his colleagues at the Santa Fe Institute and Wageningen University researched the history of global temperature, human population, and land-use estimates from the mid-Holocene period, starting about 6 thousand years ago to current times.

Researchers discovered that people, crops, and livestock had concentrated heavily in a narrow range of comparatively restricted climate conditions. This range referred to in the analysis as the “human climate niche,” has remained primarily unchanging since 6,000 years ago.

These 6,000 years of human history reveal how society thrives when we remain within it and the instability that occurs when it is moved out of these climatic zones.

According to the research, the optimum conditions for human civilization to flourish have a mean annual temperature of 11 to 15° C (51.8 to 59 °F). The ideal average temperature for national economic success is 13°C (55.4°F). Overall economic productivity is non-linear in temperature for all nations, with productivity culminating at an annual average temperature of 13 °C and decreasing strongly at higher temperatures.

The contemporary production of crops and livestock is mainly limited to the same climatic conditions, and the exact optimum has been seen for agricultural and nonagricultural economic output of nations through analyses of year-to-year variation.

The Optimum conditions for human society to flourish

For mapping territories with mean annual temperature from 11°C to 15°C (51.8 to 59 °F), I used the raster image of the bioclimatic variable of Annual Mean Temperature (BIO1). According to the map globally, the Earth’s surface area with optimal conditions for human society to flourish is about 7.7 million square kilometers or 3,0 million square miles.

Countries by area of land with optimal conditions for human society to flourish

The wealthiest country in the world with the highest GDP, the United States, has the largest area with the optimum conditions for human society to flourish. Second place in the ranking of countries with optimal climatic conditions for flourishing humanity is the world’s second economy–China.

The top 10 countries with the most significant area with the optimum conditions for human society to flourish

Rank	Country	Area in sq km	Area in sq mi
1	United States	1,602,350	618,671
2	China	1,390,310	536,802
3	Argentina	512,823	198,002
4	Iran	350,084	135,168
5	Australia	308,044	118,936
6	Uzbekistan	276,460	106,742
7	Spain	268,074	103,504
8	Turkey	247,142	95,422
9	France	238,614	92,129
10	Kazakhstan	231,363	89,330

Below is the map of the percentage of land areas with optimal conditions for humanity to flourish by country, according to the research of Marten Scheffer and his colleagues.

Percentage of land areas with optimal conditions for human society to flourish by country

Uzbekistan, the birthplace of one of the world’s ancient civilizations, has the highest percentage of land areas with the optimum conditions for human society to flourish.

The top 10 countries with the highest percentage of land areas with the optimum conditions for human society to flourish

Rank	Country	Percentage
1	Uzbekistan	65
2	Azerbaijan	64
3	South Korea	59
4	Italy	55
5	Monaco	55
6	Spain	54
7	Bulgaria	50
8	Greece	49
9	Lesotho	48
10	France	43

Land area with optimal conditions for human society to flourish per capita by country

Below is the map of a land area with optimal conditions for human society to flourish per capita and the map of countries by the number of people per square kilometer of land area with optimal climatic conditions for human society to flourish.

Full-size maps you can find here and here.

The top 10 countries with the largest land areas with the optimum conditions for human society to flourish per capita

Rank	Country	Area in hectares per person
1	Croatia	5.3
2	Monaco	3.4
3	Turkmenistan	2.9
4	Italy	2.8
5	New Zealand	2.6
6	Kazakhstan	1.5
7	Australia	1.5
8	Argentina	1.3
9	Uzbekistan	1.0
10	Chile	1.0

Even nowadays, despite the many technological advances that have helped us create comfortable conditions even in the earth’s most inhospitable regions, the climate continues to influence the development of civilization, as it did thousands of years ago. But as the climate changes, the territories that fit within the human climate niche will also change.

Further warming will harm the economies of many countries, especially those that are densely populated. Such countries as India, Indonesia, Brazil, and Nigeria are already much warmer, representing the impact of climate change on their economic growth will be even greater. Nowadays, about 0.8% of the planet’s surface experiences mean annual temperatures above 29° Celsius (84.2°F), especially in the Sahara region of Africa. However, with forecasted rises in global average surface temperatures, this area is expected to enlarge significantly to cover almost 19% of the global land. According to some research, a result of climate change that shifts climatic zones would leave 1 – 3 billion people outside the climate conditions that have nurtured human society to date. This would not be a massive problem if few people lived in that part of the world, but it is one of the world’s fastest-growing areas.

According to the researchers, the human climate niche is projected to shift remarkably to higher latitudes. So at present, the United Kingdom and Germany are cooler than 13°C, meaning their economies may improve slightly as temperatures increase.

The maps below show how the optimum conditions for human society to flourish will change by the end of the 21st century

The Optimum conditions for human society to flourish in 2100

By 2100, Europe’s climate, except for the southern part, will be even more comfortable. The zone with the most comfortable climate in North America will be mainly located along the border between the United States and Canada.

For creating the map below, I used future climate data from the Coupled Model Intercomparison Project Phase 6 (CMIP6) for the general circulation model MIROC6 and climate projection ssp585.

Globally, the Earth’s surface area with optimal conditions for human society to flourish will increase by 32% from 7,738,067 to 11,390,271 square kilometers (from 2,987,684 to 4,397,808 sq mi).

Countries by area of land with optimal conditions for human society to flourish in 2100

By the end of the 21st century, the United States, China, Russia, and Kazakhstan will have the most expansive territories with a comfortable climate for life and economic development.

The top 10 countries with the most significant area with the optimum conditions for human society to flourish in 2100

Rank	Country	Area in sq km	Area in sq mi
1	United States	2,421,176	934,821
2	China	1,639,005	632,823
3	Russia	1,151,595	444,633
4	Kazakhstan	1,018,858	393,383
5	Argentina	453,201	174,982
6	Canada	447,391	172,739
7	Ukraine	414,358	159,985
8	Germany	346,801	133,902
9	Poland	308,660	119,174
10	Mongolia	252,961	97,669

Percentage of land areas with optimal conditions for human society to flourish by country in 2100

Climatic changes will also benefit northern, central, and eastern Europe. The territories of some European countries will be almost entirely in the zone with optimal climatic conditions for human society to flourish.

The top 10 countries with the highest percentage of land areas with the optimum conditions for human society to flourish in 2100

Rank	Country	Percentage
1	Netherlands	100
2	Estonia	99
3	Lithuania	98
4	Poland	96
5	Belarus	95
6	Germany	94
7	Denmark	93
8	Ireland	91
9	Latvia	91
10	Czech Republic	90

Land area with optimal conditions for human society to flourish per capita by country in 2100

The UN forecasts that world population growth will slow considerably for the 21st century, coming near to its peak at 10.9 billion by 2100. The most populous countries in 2100 will still be China and India. There will be 1.4 billion people in each of these countries.

Unfortunately, the climate of the most densely populated countries in Asia and Africa will become less comfortable for living and economic development.

Below is the map of a land area with optimal conditions for human society to flourish per capita and the map of countries by the number of people per square kilometer of land area with optimal conditions for human society to flourish by the end of the 21st century created using UN data on the projected population in 2100.

Full-size maps you can find here and here.

The sparsely populated countries of northern and eastern Europe will benefit from the increase in the average annual temperature.

The top 10 countries with the largest land areas with the optimum conditions for human society to flourish per capita in 2100

Rank	Countries	Area in hectares per person
1	Latvia	6.2
2	Greenland	5.7
3	Estonia	5.3
4	Mongolia	4.8
5	Lithuania	4.3
6	Belarus	3.2
7	Kazakhstan	3.0
8	New Zealand	2.1
9	Ukraine	2.0
10	Montenegro	1.6

Expected Net Area Change of Land with Optimal Conditions for Human Society to Flourish per capita to 2100

In absolute numbers, Russia, the U.S., and Kazakhstan will benefit most from climate change, while Iran, Uzbekistan, Spain, and Australia will lose the most.

If we consider the change in the area of territories with the most comfortable climatic conditions per capita, the European countries will primarily benefit.

Below are the maps that show the expected net area change of land with optimal conditions for human society to flourish in total (map on the left) and per capita (map on the right) by 2100.

Full-size maps: 1, 2

Top 10 countries with the highest and lowest growth of an area of land with optimal conditions for human society in hectares by 2100

Rank	Country	Change in an area in hectares by 2100	Rank	Country	Change in an area in hectares by 2100
1	Russia	+108 964 000	1	Iran	-28 917 900
2	United States	+81 882 600	2	Uzbekistan	-26 883 600
3	Kazakhstan	+78 749 500	3	Spain	-23 903 100
4	Canada	+44 739 100	4	Australia	-20 661 700
5	Ukraine	+40 049 300	5	South Africa	-16 861 100
6	Germany	+34 677 100	6	Mexico	-16 004 600
7	Poland	+30 866 000	7	Turkmenistan	-14 018 300
8	Mongolia	+25 296 100	8	Italy	-13 912 400
9	China	+24 869 500	9	Algeria	-7 454 600
10	Belarus	+20 771 800	10	Morocco	-6 434 800

Top 10 countries with the highest and lowest growth of an area of land with optimal conditions for human society in hectares per person by 2100

Rank	Country	Change in an area in hectares per person by 2100	Rank	Country	Change in an area in hectares per person by 2100
1	Latvia	+6.2	1	Croatia	-5.0
2	Greenland	+5.7	2	Monaco	-3.4
3	Estonia	+5.3	3	Turkmenistan	-2.9
4	Mongolia	+4.8	4	Italy	-2.7
5	Lithuania	+4.3	5	Australia	-1.3
6	Belarus	+3.2	6	Uzbekistan	-1.0
7	Ukraine	+1.9	7	Colombia	-0.9
8	Kazakhstan	+1.5	8	Lebanon	-0.6
9	Poland	+1.3	9	Spain	-0.5
10	Montenegro	+1.2	10	Azerbaijan	-0.5

According to the researchers, business-as-usual climate change scenario, the geographical position of this temperature niche is forecasted to shift more over the coming 50 years than it has shifted since 6000 BP. As a result, climate change’s effect will massively increase global income inequality and reshape the global economy by decreasing average global incomes by roughly 23% by 2100. Populations will not simply track the shifting climate; adaptation in situ may address some challenges, and many other factors affect migration decisions.