This story appears in the December 2018 issue of National Geographic magazine.

The world’s richest countries, such as Luxembourg and the United States, have average incomes per person about 100 times higher than in the poorest countries, such as Burundi and the Democratic Republic of the Congo. That’s a tragedy for poor countries. Is it also a looming tragedy for rich ones?

Until recently all those poor people elsewhere were no threat to rich countries. “They” out there didn’t know much about our lifestyle—and even if they did and became angry, they couldn’t do anything about it.

But today, poor remote countries are able to create problems for rich ones, and the reasons can be summed up in a word: globalization. As a result of the increased connections among all parts of the world, people in developing countries know more about differences in living standards, and many of them can now travel to rich countries.

Globalization has made it untenable for such dramatic inequalities between high and low living standards to persist. I see evidence of that everywhere, but three examples stand out.

G R O S S N A T I O N A L I N C O M E P E R C A P I T A * INCOME IMBALANCE Today over a third of the world’s income is generated by about a tenth of the world’s population in wealthy countries. As incomes rise in poorer nations, consumption will rise also, thus depleting more natural resources to achieve a more affluent lifestyle. Asia South America Africa Oceania All Countries North America Europe Circles sized to population. Hover over each circle for more information. War and social ills keep Liberia poor despite abundant natural resources. Nations to the right of this line account for 38% of the world’s income but only 12% of the world’s population. Romania 20 million $20,049 Equatorial Guinea 1 million $23,324 Croatia 4 million $20,848 Chile 18 million $21,854 Kazakhstan 18 million $23,164 Latvia 2 million $22,889 Turkey 78 million $23,125 Russia 144 million $23,909 Hungary 10 million $23,740 Greece 11 million $24,251 Poland 38 million $24,418 Malaysia 31 million $24,324 Portugal 10 million $25,860 Lithuania 3 million $25,922 The Bahamas 386,838 $27,602 Estonia 1 million $26,985 Slovakia 4 million $27,851 Czechia 11 million $28,567 Slovenia 2 million $28,371 Cyprus 1 million $30,744 Israel 8 million $31,734 Spain 46 million $32,217 New Zealand 5 million $33,643 Malta 445,053 $32,755 South Korea 51 million $34,276 Italy 61 million $34,115 United Kingdom 65 million $38,146 France 67 million $38,367 Oman 4 million $38,980 Japan 127 million $39,322 Finland 5 million $39,248 Belgium 11 million $41,727 Bahrain 1 million $42,178 Iceland 330,815 $42,425 Canada 36 million $42,512 Luxembourg 569,604 $44,155 Australia 23 million $43,138 Austria 8 million $43,984 Germany 82 million $44,766 Netherlands 17 million $46,239 Sweden 10 million $46,380 Denmark 6 million $47,000 Ireland 4 million $48,551 Saudi Arabia 32 million $51,885 United States 321 million $53,741 Hong Kong, China 7 million $54,608 Switzerland 8 million $58,280 United Arab Emirates 9 million $66,923 Norway 5 million $67,028 Kuwait 4 million $73,657 Singapore 5 million $78,742 Brunei 417,542 $78,611 Marshall Islands 52,994 $4,983 Bangladesh 161 million $3,334 Cambodia 15 million $3,086 Mauritania 4 million $3,505 Kenya 47 million $2,806 Malawi 17 million $1,052 Côte d’Ivoire 23 million $3,142 Niger 20 million $889 Afghanistan 34 million $1,824 Uganda 40 million $1,635 Zimbabwe 16 million $1,678 Ethiopia 100 million $1,527 Central African Republic 4 million $624 Burundi 10 million $748 Togo 7 million $1,374 Burkina Faso 18 million $1,527 Sierra Leone 7 million $1,297 Madagascar 24 million $1,323 Haiti 11 million $1,658 Guinea-Bissau 2 million $1,485 The Gambia 2 million $1,518 Mozambique 28 million $1,093 Tanzania 54 million $2,449 Nepal 29 million $2,353 Cameroon 23 million $3,243 Guinea 12 million $1,664 Democratic Republic of the Congo 76 million $750 Yemen 27 million $2,229 Chad 14 million $2,014 Lesotho 2 million $3,039 Mali 17 million $1,865 Sudan 39 million $3,938 Rwanda 12 million $1,688 Liberia 4 million $694 Senegal 15 million $2,230 Benin 11 million $1,980 Ghana 28 million $3,861 Honduras 9 million $4,023 Kyrgyzstan 6 million $3,086 Republic of the Congo 5 million $7,418 Pakistan 189 million $4,978 Nicaragua 6 million $5,010 Moldova 4 million $5,084 Cabo Verde 532,913 $5,692 Uzbekistan 31 million $5,811 Nigeria 181 million $5,527 Vietnam 94 million $5,263 India 1.3 billion $5,691 Laos 7 million $5,523 Angola 28 million $6,251 Bolivia 10 million $6,345 Guatemala 16 million $7,108 Morocco 35 million $7,154 El Salvador 6 million $7,563 Timor-Leste 1 million $8,003 Ukraine 45 million $7,375 Bosnia & Herzegovina 4 million $11,004 Bhutan 787,386 $7,066 Paraguay 7 million $8,192 Jamaica 3 million $7,841 Belize 359,288 $7,666 Eswatini 1 million $7,836 Philippines 102 million $8,323 Armenia 3 million $8,517 Georgia 4 million $8,766 Jordan 9 million $8,392 Indonesia 258 million $10,037 Mongolia 3 million $10,511 Dominican Republic 10 million $12,655 Kosovo 2 million $9,307 Egypt 94 million $9,923 Sri Lanka 21 million $10,791 Namibia 2 million $9,929 Albania 3 million $11,083 Ecuador 16 million $10,567 South Africa 55 million $12,073 Macedonia 2 million $12,336 Peru 31 million $11,420 Colombia 48 million $12,772 Serbia 7 million $12,601 Algeria 40 million $13,338 Lebanon 6 million $13,174 China 1.4 billion $13,519 Costa Rica 5 million $14,086 Palau 21,288 $13,400 Montenegro 622,159 $15,702 Botswana 2 million $15,109 Thailand 69 million $14,455 Iran 79 million $16,537 Belarus 9 million $16,228 Mexico 126 million $16,569 Bulgaria 7 million $16,663 Gabon 2 million $16,482 Panama 4 million $18,167 Argentina 43 million $18,437 Mauritius 1 million $18,733 Uruguay 3 million $19,278 Qatar 2.5 million $117,896 Per capita oil-consumption rates in the U.S. are about double those in western Europe. Prosperous Qatar’s natural gas reserves represent almost one-sixth of the world’s total. 60K 10K 20K 0 30K 40K 50K 70K 90K 110K 120K 80K 100K GROSS NATIONAL INCOME PER CAPITA* Taylor Maggiacomo, NGM staff. Source: world bank; world factbook *2015, adjusted for purchasing power parity (constant 2011 international $) INCOME IMBALANCE Today over a third of the world’s income is generated by about a tenth of the world’s population in wealthy countries. As incomes rise in poorer nations, consumption will rise also, thus depleting more natural resources to achieve a more affluent lifestyle. REGION N. America S. America Europe Africa Asia Oceania Circles sized to population Gross National Income per capita* (There is no x-axis.) 120K Qatar, 2.5 million people 110K 100K 90K Singapore 80K Brunei 70K 60K United States, 321 million 50K Australia 40K U.K. Nations above this line account for 38% of the world’s income but only 12% of the world’s population. 30K Russia 20K India Colombia 10K China 1.4 billion Liberia 0 D.R. Congo Burundi *2015, adjusted for purchasing power parity (constant 2011 international $) Taylor Maggiacomo, NGM staff. Source: world bank INCOME IMBALANCE Today over a third of the world’s income is generated by about a tenth of the world’s population in wealthy countries. As incomes rise in poorer nations, consumption will rise also, thus depleting more natural resources to achieve a more affluent lifestyle. N. America S. America Europe Africa Asia Oceania REGION Circles sized to population. Nations to the right of this line account for 38% of the world’s income but only 12% of the world’s population. Liberia Colombia United States 321 million Qatar 2.5 million Russia U.K. Brunei India Australia Singapore China 1.4 bil. 60K 20K 0 10K 30K 40K 50K 70K 80K 90K 100K 110K 120K Gross National Income per capita* *2015, adjusted for purchasing power parity (constant 2011 international $) Taylor Maggiacomo, NGM staff. Source: world bank

The first is health. The spread of disease is an unintended result of globalization. Feared diseases now get carried to rich countries by travelers from poor countries where the diseases are endemic and public health measures are weak. The diseases include old ones like cholera and flu, plus new ones like AIDS, Ebola, and Marburg. For instance, in 1992, when an Argentine airliner picked up cholera-infected food in Peru and flew nonstop to Los Angeles, some passengers then flew on to Seattle, Alaska, and Tokyo, resulting in a trail of cholera cases from California to Japan.

Second: terrorism. Global inequality itself isn’t the direct cause of terrorist acts. Religious fundamentalism and individual psychopathology play essential roles. Every country has its crazy, angry individuals driven to kill; poor countries have no monopoly on them. But in poor countries today, people are barraged with media visions of lifestyles that are available elsewhere in the world and unavailable to them. In anger and desperation, some become terrorists themselves; others tolerate or support terrorists.

Since the September 11, 2001, attacks on the Pentagon and New York City’s World Trade Center towers, it’s been clear that the oceans that formerly protected the United States no longer do. Americans now live under constant threat of global terrorism. I predict that there will be more terrorist attacks against the United States, Europe, Japan, and Australia—as long as big differences in living standards persist.

The third result when inequality and globalization collide is that people with spartan lifestyles want affluent ones. In most developing countries, increasing living standards is a top policy goal. But millions of people in those countries won’t wait to see whether their government can deliver higher living standards within their lifetime.

Instead they seek more affluent lifestyles now by immigrating to developed countries, with or without visas: especially to western Europe, the United States, and Australia; and especially from Africa, Asia, and Latin America. Whether immigrants are seeking economic opportunity, a haven from violence, or political asylum, it’s proving impossible to control recent waves of migration around the world.

But it won’t be possible for everyone to achieve the dream of the developed-world lifestyle. Just do the math.

An average consumption rate per person means the amount of oils and other resources that the average person consumes a year. In rich countries those rates are up to 30 times as high as they are in poor countries.

Multiply each country’s current population by its average per-person consumption rate for a resource—say, oil—and add up those amounts over the whole world. The resulting sum is the world’s current consumption rate of that resource.

Now repeat that calculation, but with all developing countries achieving consumption rates up to 30 times as high as their current ones.

The result: World consumption rates increase by about 10-fold. That’s equivalent to a world population of nearly 80 billion people with the current distribution of consumption rates. Some optimists claim that Earth can support 9.5 billion people. But no optimist is crazy enough to claim that the world can support the equivalent of 80 billion people.

We promise developing countries that if they just adopt good policies such as honest government, they too can enjoy affluence—but that promise is a cruel hoax. The world doesn’t contain enough resources. We’re already having difficulty supporting a developed-world lifestyle now, when only about one billion people of the world’s 7.5 billion enjoy it.

Americans often refer to growing consumption in China and other developing countries as “a problem” and wish that the “problem” didn’t exist. Of course it will persist: People of other countries want to enjoy the consumption rates that Americans enjoy. They wouldn’t listen if told not to do what Americans are already doing. The only sustainable outcome for our globalized world is one in which consumption rates are more nearly equal around the planet. But we can’t sustainably support today’s developed world at its current level, let alone raise the developing world to that level.

Does that guarantee that we will end up in disaster? No! We could have a stable outcome in which all countries converged on consumption rates below what developed nations enjoy now. Americans may object: We won’t sacrifice our living standards for the benefit of those other people out there! As former U.S. Vice President Dick Cheney once said, “The American way of life is nonnegotiable.” But cruel realities of world resource levels guarantee that the American way of life will change, like it or not. Those realities can’t be negotiated.

As alarming as that may sound, I believe it wouldn’t be a significant sacrifice. Why? Because consumption rates and well-being, although related, aren’t tightly coupled. Much U.S. consumption is wasteful and doesn’t contribute to quality of life. For example, per capita oil-consumption rates in western Europe are about half those in the United States—and yet the average western European’s well-being is higher than that of the average American by any meaningful criterion, such as financial security after retirement, health, infant mortality, life expectancy, and vacation time. When you finish reading this page, go out into any U.S. street, look at the cars driving by, estimate their gas mileages, and ask yourself whether those wasteful mileages contribute positively to any meaningful measure of quality of life.

Here’s the bottom line: It’s certain that within our lifetimes, per capita consumption rates in the developed world will be lower than they are now. The only question is whether we’ll reach that outcome by methods of our choice or by unpleasant methods not of our choice. It’s also certain that within our lifetimes, per capita consumption rates in developing countries will no longer be one-thirtieth of developed countries’ rates but will be more nearly equal to them. Those trends are desirable goals, rather than horrible prospects to be resisted. We already know enough to make progress toward achieving them; what’s lacking is the necessary political will.

Should we be depressed by the consequences of inequality? Again, no! While problems are getting worse, potentials for solutions are getting better. Multinational or world agreements have already succeeded in solving some big problems. Hence I view our world as being engaged in a horse race between a horse of destruction and a horse of hope. The race isn’t a normal one, in which both horses run at a constant speed. Instead it’s an exponentially accelerating race in which each horse is running faster and faster. Within a few decades we shall know which of those two horses has won the race.