Humanity faces a growing complex of serious, highly interconnected environmental problems, including challenges such as climate change, as well as the equally, or more, serious threat to the survival of organisms that support our lives by providing critical ecosystem services, such as crop pollination and agricultural pest control.
But our guess is that the most serious threat to global sustainability in the next few decades will be one on which there is widespread agreement: the growing difficulty of avoiding large-scale famines. As the 2013 World Economic Forum Report put it: “Global food and nutrition security is a major global concern as the world prepares to feed a growing population on a dwindling resource base, in an era of increased volatility and uncertainty.”
In fact, virtually all such warnings, in our view, underestimate the food problem. For example, micronutrient deficiencies may afflict as many as two billion additional people. And many other sources of vulnerability are underrated: for example, the potential impact of climate disruption on farming and fisheries and how a shift away from fossil-fuel consumption will impair food production.
Perhaps most important, virtually all analyses assume that the human population will grow by 2.5 billion people by 2050, rather than seeking ways to reduce that number. The optimism of many analysts concerning our ability to feed these additional billions is quite disturbing.
Five steps are typically recommended to solve the food problem: stop increasing land for agriculture (to preserve natural ecosystem services); raise yields where possible; increase the efficiency of fertiliser, water, and energy; become more vegetarian; and reduce food wastage. To this one could add, stop wrecking the oceans, greatly enlarge investment in agricultural research and development, and move proper nutrition for all to the very top of the global policy agenda.
All of these steps require long-recommended changes in human behaviour. Most people fail to recognise the growing urgency of adopting them because they do not understand the agricultural system and its complex connections to the mechanisms driving environmental deterioration.
All inputs needed to feed each additional person will, on average, come from scarcer, poorer, and more distant sources, disproportionately more energy will be used, and disproportionately more greenhouse gases will be generated.
More than a millennium of changing temperature and precipitation patterns, all vital to crop production, has put the planet on a path toward increasingly severe storms, droughts, and floods. Thus, maintaining – let alone expanding – food production will be increasingly difficult.
A popular movement is needed to direct cultural awareness toward providing the “foresight intelligence” and the agricultural, environmental, and demographic planning that markets cannot supply. Only then could we begin to address seriously the population disaster.
The best way, in our view, to achieve such population shrinkage is to give full rights and opportunities to women, and to make modern contraception and back-up abortion accessible to all sexually active people.
• Paul Ehrlich is professor of population studies, department of biological sciences, Stanford University.