Sharp changes are afoot throughout the globe. Demographics are shifting, technology is advancing at unprecedented rates, and these changes are being felt everywhere. How should we develop strategies to deal with this emerging new world? We can begin by understanding it. First, there is the changing composition of the world population, which will have a profound impact on societies. Developed countries are experiencing falling fertility and increasing life expectancy. As working-age populations shrink and pensions and care costs for the elderly rise, it becomes harder for governments to afford other productive investments.
Human societies have generally made great progress over the course of history in the mastery of their surrounding environments, climates, and biomes. And the experience of the United States is emblematic of this, across a variety of measures—with significant reductions in air and water pollution, in weather-related mortality, in malnutrition, and in the burden of disease. Progress has been driven by a combination of technology, markets, and governance. Oftentimes difficult social and regulatory choices over the past half century, enabled by technological innovation and ongoing incentives for investments, have allowed this country to stay one step ahead of the variety of environmental and health risks it faces.
Infectious disease has been a formidable force in shaping human history. In the times past, most people died from two causes: violence and infectious disease, with deaths from infectious disease being many times more common. Bubonic plague killed between a third and a half of the population of Europe in the Middle Ages, thus changing the course of Europe and the world forever. Smallpox killed half a billion people in the 20th century alone before being finally eradicated in 1982.
We are intimately connected to the world around us—to the air, water, and soil that envelop us. The average adult constantly replenishes the oxygen within them by taking 12 to 20 breaths per minute; we regularly consume water, which constitutes over 50% of our body weight; we obtain most of our vital nutrients from the soil through the foods we consume. A healthy vibrant biosphere is vital for our wellbeing.
The familiar photo of the Earth spinning in the blackness of space that was taken 50 years ago by William Anders, an astronaut on the Apollo 8 lunar mission, starkly illustrated our isolation on this planet. Now we face a crisis as the climate and environmental conditions that support life as we know it become ever more fragile owing to CO2-induced global warming. The evidence suggests there is significant risk that areas of the Earth in tropical zones may become uninhabitable and that significant food chains will collapse in this century.
As you have heard from the other speakers today, there are numerous health risks associated with global climate change. The Union of Concerned Scientists has analyzed this question and concluded that: “Rising temperatures will likely lead to increased air pollution, a longer and more intense allergy season, the spread of insect-borne diseases, more frequent and dangerous heat waves, and heavier rainstorms and flooding. All of these changes pose serious, and costly, risks to public health.”