Don't tell Jonathan Franzen. The population of the world, rather than stabilizing around nine billion in the middle of the century as previously expected, is now projected by the United Nations to hit 10.1 billion by century's end. The world population is expected to pass seven billion in late October of this year, just a dozen years after passing six billion. The high projection is due partly to the fact that fertility isn't declining as fast as expected in some poor countries, and has increased slightly in many wealthier ones, like the United States, Britain, and Denmark. The director of the U.N. Population division, Hania Zlotnik, said the world's fastest-growing countries and the wealthy Western nations that finance their development face a choice about whether to renew their emphasis on family planning programs. The projection assumes that food and water will be available for the billions of future people, and that climate change or epidemics won't slow growth. That assumption might not be accurate in all cases—Yemen, whose population has quintupled since 1950 and is expected to quadruple again to 100 million by 2100, already depends on food imports and faces critical water shortages. “It is quite possible for several of these countries that are smallish and have fewer resources, these numbers are just not sustainable,” says Zlotnik.