Since the 19th century, and more intensively since the 1960s, demographers like Paul Ehrlich, who was interviewed in this magazine last week, have been telling us that the world is a ticking bomb because of the population explosion. When we think about the “population explosion” we conjure up street crossings in New York or, alternatively, refugee camps in the Gaza Strip. But the truth is that the world is quite empty of people. If every person in the world were to stand at touching distance from one another, they would occupy the whole territory of Israel, not including Judea, Samaria, Gaza, the Golan Heights and East Jerusalem.

That’s all. The rest of the world would be devoid of humans.

And if 7 billion people still strikes you as too many to live together peacefully, take into account that world population density stands at 45.3 people for every square kilometer of land. By comparison, the population density in Tel Aviv is, according to the Central Bureau of Statistics, 7,995 people per square kilometer. In other words, if all human beings lived in one big Tel Aviv, that world city would occupy an area equivalent to that of Egypt. All the rest of the world would be one big happy nature reserve.

In fact, if there is a “demographic problem,” it is the very opposite. “For decades, people took dynamism and economic growth for granted and saw population growth as a problem,” David Brooks wrote last March in The New York Times. “Now we’ve gone to the other extreme, and it’s clear that young people are the scarce resource.” So scarce are young people that most Western countries are bribing their citizens to be fruitful and multiply. The town of Yamatsuri, in Japan, for example, offers $4,600 for every newborn baby, plus $460 a year for the first 10 years of the child’s life.

Cause for optimism

But population ageing is not only a Western problem. On the contrary: despite the masses of frenzied young people we see on TV all the time, the Arab states are actually ageing more rapidly than anywhere else, and their populations are shrinking at the fastest rate in history.

According to the report of the UN Population Fund for 2011, the all-time record was broken in Oman, where every woman gives birth to an average of 5.6 fewer children than her mother did. The other shrinkage records also belong to our Arab neighbors. Within one generation, the fertility rate in Syria, Saudi Arabia and Morocco diminished by 60 percent, and Iran registered a steeper decrease, of 70 percent. In fact, Iran’s birth rate is similar to that of New England, which has the lowest fertility rate in the United States, while Turkey is on a par with Alabama, Tunisia with Illinois, and the Lebanese birthrate is lower than that of New York.

Still worried by 7 billion people? Have no fear: most people live in countries with a negative natural population increase, and the UN estimates that in 2050 the world’s population will be 9.2 billion − and that will be that. In 2050 the global rate of natural increase will be zero. For the first time since the plague in the 14th century, the world’s population will shrink.

Population ageing, and finally, population shrinkage will generate immense economic, social and cultural challenges to a world based on constant growth and renewal.

But here in Israel, those challenges can present a genuine opportunity. True, Israel’s population is also getting older. According to the report of a committee established to plan a national geriatric infrastructure, which was submitted last year to the director general of the Health Ministry, by 2030 there will be 1.3 million Israelis above the age of 65, representing a rise of 84 percent in the elderly population. However, population ageing in Israel is a special case − compared with both the West and the Arab states − since it combines a rise in life expectancy with an increase in the fertility rate.

Yes, that rate has gone up in Israel in recent years: every Jewish mother now has an average of three children − more than her sisters in Iran, Syria or Egypt.

What about our brothers the Palestinians? In contrast to the Arab states, statistics about their fertility rate are the object of constant debate. The figures issued by the Palestinian Central Bureau of Statistics are frequently inflated for political and economic reasons. The Begin-Sadat Center for Strategic Studies at Bar-Ilan University found a disparity of 40 percent − representing one million Palestinians − between the fertility rate according to the Palestinian CBS and actual births as recorded by the Palestinian Health Ministry.

Both Palestinian agencies agree on one thing: Palestinians are giving birth to far fewer children. Until the 1990s, a Palestinian woman gave birth to an average of six to eight children. That rate has now decreased to three to five children, and if we can trust the Palestinian Health Ministry’s registration of births, the rate is decreasing and has already reached the same level as that of the Jewish population, which is on the upswing.

That is good reason for optimism, even beyond the Jews’ desire to preserve a Jewish majority between the Jordan and the Mediterranean. It’s reason for optimism because the number one reason for the unprecedented fall in the fertility rate in the Arab world is optimism without a reason − which is itself a reason for optimism.

In an article titled “The Islamic World’s Quiet Revolution” ‏(Foreign Policy, March 2012‏), Nicholas Eberstadt, from the American Enterprise Institute, writes that the decreasing fertility rates constitute a development that “flies in the face of the conventional views of population policy specialists, in which ‏– to exaggerate only slightly – women mechanistically respond to changes in the socioeconomic environment ... But at the end of the day, current fertility levels ‏(in both Muslim and non-Muslim societies‏) seem to be a product of intangible factors ‏(culture, values, personal hopes and expectations‏), not just material and economic forces.” In other words, Arab men and Arab women are hoping for a better future in the Middle East, even if they have no reason to believe in such a future.

Of course, low birthrates go hand in hand with secularization processes, economic growth and modernization, but it’s not clear which is the reason and which the cause. “In particular,” Eberstadt notes, “proponents of purely material models of development are confronted by the awkward fact that the fertility decline over the past generation has been more rapid in the Arab states than virtually anywhere else on Earth. Yet few people disagree that those same countries have exceptionally poor development records over the same period.”

Just ask

The models to which Eberstadt refers were used to explain the decrease in the birthrate in Europe at the end of the 19th century, and − at least in the perception of public opinion − have remained unchanged ever since. According to demographic transition theory, societies develop in three stages. In the first stage, the birth and mortality rates are very high and thus “eliminate” each other, leaving no demographic or economic growth. In the second stage, processes of industrialization and urbanization reduce the mortality rate without affecting the birthrate, generating demographic and economic growth. And finally, natural increase stabilizes as more and more families adjust the fertility rate to a long, thriving life.

But not only does this 19th-century European model fail to work for the 21st century; it doesn’t even work for 19th-century Europe. “For instance, in half the districts of Germany, parents had fewer babies before their prospects for survival improved,” Matthew Connelly, from Columbia University, notes in “Fatal Misconception: The Struggle to Control World Population” ‏(paperback edition, Belknap Press, 2010‏). “England and Belgium showed the same, seemingly inverse, relationship, while analyses of local data and infant mortality in many other countries revealed no correlation at all ... In fact, in most of Europe changes in reproductive behavior came nearly simultaneously in urban and rural areas, such that farmers had families more similar to those of their cousins in the city than to those in a different region.”

What, then, if not economic growth and a longer lifespan, accounts for the transition from a society of large families to an ageing one with small families? In 1994, the economist Lant Pritchett found that the best way to predict how many children a woman will bear is simply to ask her. “Women mean what they say,” Pritchett wrote, and proved that women’s expectations for the continuation of their lives is the number-one factor in family planning − not the availability of condoms or a rise in GNP.

Indeed, the Middle East is ageing because the Middle East hopes to age honorably. By 2040, the stone-throwing children of the first intifada will be men of retirement age, and they wish for a better life for them and for their children. By 2040, the slogan “We have no children for unnecessary wars” will be more apt than ever.