We humans have certainly met—and exceeded—the Biblical injunction to “go forth and multiply.”

Since reliable figures have been available in the early 1800s, the world’s population was at less than one billion people. By the 1950s, it had risen tonearly 2½ billion and then exploded—due mainly to an incredible increase in global food productivity, let’s not forget—to the more than 6.5 billion where we currently stand.

That’s a doubling of the world’s population in less than 50 years.

How much more of an increase can the planet’s already strained resources and ecosystems take? Are we destined as a species to simply overpopulate our habitat?

Hopefully not.

For all the organizations that make long-term projections of population growth, the most common assumption is that the global population will peaks ataround 9.22 billion in 2075, give or take a several hundred million people. However, after reaching itsmaximum, the world’s population will then decline slightly to reach a levelof 8.97 billion by 2300.

At least that’s the (somewhat) hopeful prediction contained in a special report, “World Population to 2300,” compiled by the United Nations’ Department of Economic and Social Affairs of the United Nations Secretariat.Although this report is several years old now, it’s one of the few that, considering the challenge of feeding a burgeoning population, contains somewhat optimistic forecasting.

And that’s saying something for an organization that specializes in doomsday predictions.

Why is there optimism in projections about another 3 to 4 billion mouths to feed? Because global fertility rates, which has been astronomically high, are projected to decline sharply in the next century. Although it varies from country to country, global fertility will fallbelow replacement level—though in some casesnot for decades—and eventually return to replacement levels, meaning that the world’s population will eventually stabilize.

Sobering numbers

In terms of numbers, the average annualpopulation growth rate over the next half-century willbe 0.77%, substantially lower than the 1.76% average growth rate from 1950 to 2000; by 2045-2050, it will be only 0.33%.

The report offers a few other interesting projections about how the world’s population will be distributed:

  • From 2000 to 2100, Europe’s shareof world population will be cut in half, from 12% to 5.9%, while Africa’s share almost doubles, from 13.1% to24.9%.
  • Asia will grow fastest in the west but with growthrates (through 2100)Africa; by 2100, Asiawill be only 2.2 times as populous as Africa.
  • North America is the only regionthat will not experience negative growth rates,mainly due to projected migration, up to 2050.
  • The world medianage now stands at about 26 years; by 2100 it will be 44years; by 2300, 48 years.

Of course, no matter where the world’s population levels off, whether it’s 9 billion or 9.75 billion, we collectively face enormous challenges in providing adequate food and nutrition to so many more mouths. We know that economic forecasting is probably even less accurate than demographic projections, but as global gross domestic product per capita has increased substantially in virtuallyarea of the world, that has created added demand for meat, poultry and dairy. That’s in addition to a worldwide 43% increase in cropland and a nearly 10% increase in grazingland.

Although populations could surpass even the UN’s relatively bold projections, we know for a fact that cropland and grazing acreage cannot.

Perhaps the most important short-term change that could help meet the feeding the world challenge, according to the report, is termination—or at least substitution—of the consumption of food crops for biofuel. In the 1970s, there was relentless pressure from activists to switch from eating meat to eating grains, the assumption being that the world couldn’t grow enough to feed both people and livestock.

That proved wrong, as significant agricultural productivity gains wiped that theory off the map. Such an exponential increase is far less likely in the next 50 years, so the food-for-fuel controversy is likely to be one that only increases in urgency the remainder of this century.

There is one silver lining in the report, and that’s on the subject of life expectancy. Between 2100 and 2300, the proportion of world’s population 65 years and older will increase from 24 to 32%, while the proportion of the population 80 years and older will double from 8.5 to 17%.

Thus, averagelife expectancy is expected to reach 74.8 years by2050; by 2225 it will be at 92.8 years.

Although we won’t be around to witness it, that means in another 200 years, 90 will be the new 80.

You gotta love that trend.

Dan Murphy is a veteran food-industry journalist and commentator