Sir David King’s Take on Climate Change

The incredible successes of science and technology in improving human existence and extending human life spans in the 20th century have spawned many of the challenges facing us in the early decades of the 21st century, Sir David King told attendees at the SACI/FACS meeting in Johannesburg in his plenary address opening the conference. Life expectancy has increased in the developed world from 45 years in 1900 to greater than 80 years today, which has resulted in a population explosion that is straining the Earth’s resources and environment. Although the population explosion will end in this century, King said, because of the education and empowerment of women and the availability of safe and effective birth control, Earth’s population will continue to increase over the next several decades. “We need 50% more crop production in the next 15 years alone, and that has to be produced on less land and available water,” King said. “We need more crop/drop and more crop/hectare.” On climate change, King said, “We hear enough from the climate change skeptics that I have to repeat some fundamentals that you’ve probably heard before.” Fifty-five million years ago, atmospheric CO2 concentrations stood at about 1,000 ppm and global temperatures were much higher and ocean levels were about 110 m higher than they are today. Large mammals developed on Antarctica because the climatic conditions on all of the other continents were inhospitable to such development. In the past 500,000 years, every ice age was characterized by atmospheric CO2 concentrations around 200 ppm; every short interglacial period by concentrations around 285 ppm, which was also the preindustrial atmospheric concentration of CO2. Today, the atmospheric CO2 concentration stands at 389 ppm and is rising by 2 ppm per year. “Could we get back to 1,000 ppm CO2 by burning all of the fossil fuel on Earth?” King asked. “Yes.” Currently, we are adding 36 billion tons of CO2 per year to the atmosphere, King said, “and that makes a difference to the atmosphere.” By 2050, we need to reduce emissions to 18 billion tons per year. With a projected population of nine billion, that translates into about 2 tons per person per year. Policies should be adopted to move us to a situation where every person on Earth emits 2 tons per year, King said, with “no exceptions.” King made many important points in his talk. One that was new to me was that we currently consume 475 exajoules (1018 joules) of primary energy resources per year to obtain just 55 exajoules of useful energy. This represents an enormous potential for energy savings through increases in the efficiency of energy conversion. King also pointed out that biofuel from algae has “massive advantages” in terms of energy production per unit of land over all other biofuels. Using open ponds and bioreactors, he said, all of the oil needs of the U.S. could be met using 200 km2 of land area. And moving toward a defossilized-fuel world need not mean that developing countries are deprived of the improvements in their living standards they have every reason to expect to enjoy, King said. We can develop national strategies for limiting climate change through low carbon economic growth in developing countries, King insisted. King concluded his talk by observing that the prospect of climate change can either leave one very depressed, believing that “this is going to be a terrible century,” or optimistic, believing that “this is just what we needed to change the path we are on.” King chooses the optimistic view of what we can accomplish in the 21st century.

Author: Rudy Baum

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