If you believe the doomsday merchants, the scariest thing about this Halloween is the fact that the world's population will pass seven billion on or near October 31.
Population growth, however, is not the biggest skeleton in the closet when it comes to our planet's ability to absorb human impact. Far more damaging than the booming birth rate in low income countries are the resource-intensive lifestyles of the global rich and middle class. Contrary to popular belief, reducing the global birth rate would not make a big dent in the amount of fossil fuels, minerals, and timber we use up. For example, if the 1.3 billion people who lack electricity today were all able to tap basic lighting and heating services by 2030, world energy demand would rise by a mere 1%, according to the International Energy Agency (IEA).
Contrast that with the destructive impact of middle class lifestyles on natural resources. In 2008, the United States consumed 39 times as much energy per person than Bangladesh, while citizens across all high income countries consumed 14 times more energy than those of low income countries.
What's more, population growth is slowly leveling off (and will be concentrated in Africa) while the global middle class is expanding exponentially. According to Goldman Sachs, 70 million more men and women enter the middle income bracket every year. By 2020, The Economist recently predicted, China's economy is likely to outgrow that of the United States. And India is only a few decades behind. Meanwhile, 60% of the Earth's ecosystem services - the very resources that underpin our modern lifestyles - are already deteriorating under our over-exploitation.
Population growth is not a negligible issue. But on a planetary scale, high-consuming lifestyles are a bigger problem.
All this is not to suggest that hard-earned middle class lifestyles must be curbed or that Africans and Asians should be denied the chance to own laptops and iPods. Far from it. Instead, as the middle class grows, business and governments need to find ways to shrink natural resource use, and ultimately decouple it from lifestyle and economic growth. This may sound a tall order, but there are several vitally important areas, including food supply and water use, where we can make a good start today.
Population change between 2010 and 2100 by major region (millions). Source: United Nations, Department of Economic and Social Affairs, Population Division (2011). World Population Prospects, The 2010 Revision. (Click to enlarge)
First, food. Worldwide, at least 30% of all food grown is lost between field and fork. In developing countries, this waste typically occurs post harvest when poorly secured crops are degraded or eaten by pests. In the developed world, consumers and the food services sector are the main culprits, throwing out mountains of uneaten perishables. How do we fix this? For consumers, education and awareness campaigns that help change wasteful habits can make a big difference on a national scale. In developing countries, simple and relatively inexpensive approaches, such as improving grain storage by building local construction skills can pay dividends. In Afghanistan, for example, such measures cut post-harvest crop losses from 20% to 2%.
Second, water. Rising water demand is outstripping supply, driven in part by the land and water-intensive needs of meat-heavy middle class diets. By 2025, 1.8 billion people will be living in water-scarce countries or regions, with alarming implications for human wellbeing and global security. With agriculture responsible for 70 percent of all freshwater use, we urgently need to find ways to produce more crop per drop.
Drip irrigation is one proven solution, increasing water use efficiency by as much as 40 percent compared with flooding fields indiscriminately with water. Other efficiency measures such as modest shifts in cropping patterns and smart irrigation scheduling also reduce the amount of water pumped for farming, and save energy and related GHG emissions in the process.
Population growth is not a negligible issue. In many local communities, it will undoubtedly cause resource crunches, human hardship and policy challenges. In the Sahel and parts of South Asia, for example, birth rates are soaring while ecosystems services such as water, wood and healthy soil are increasingly scarce. But on a planetary scale, high consuming lifestyles are a bigger problem.
Taking the kinds of corrective actions suggested above, on a global scale, is practically possible and would not cost the Earth. But not taking them might. Now that really is a scary thought.