“If usage of air-conditioning continues to grow, it could singlehandedly undermine all of humanity’s efforts to curb the release of greenhouse gases and prevent climate disruption,” says, Stan Cox, senior scientist at The Land Institute in Salina, Kansas, USA. He is the author of ‘Losing Our Cool: Uncomfortable Truths about Our Air-Conditioned World’ and ‘Any Way You Slice It: The Past, Present and Future of Rationing’.
I estimate that residential, commercial, and industrial air-conditioning worldwide is currently consuming more than one trillion kilowatt-hours of electricity annually. That’s a lot. But with demand growing fast in the earth’s warmer regions, experts project that worldwide consumption could explode tenfold by 2050.
I hope it is appropriate for me to sum up the global situation and ask, “Supposing we in the West do achieve large reductions in our greenhouse emissions from indoor climate control (along with other sources), can India and other countries with huge potential demand for air-conditioning do the same?
– Stan Cox
Having developed increasingly efficient air-conditioning technology over the past half-century, we have at the same time designed homes, businesses, and transportation systems that are completely dependent on refrigerative cooling. And as global temperatures rise, we are forced to use even more cooling. The resulting increase in greenhouse emissions, in turn, accelerates the warming and triggers even greater demand for air-conditioning.
That vicious circle must be broken. But when it comes to urging restraint in the nations of South and Southeast Asia, where much of the increase in cooling demand is expected, an American like me has the poorest of credentials. Until recently, half of all energy used worldwide for air-conditioning was consumed in the United States, while we make up only five percent of the Earth’s population. We use more energy for air-conditioning of buildings than the billion people on the continent of Africa consume for all purposes. The amount of extra petrol that U.S. vehicles consume to run their air conditioners exceeds India’s total petrol consumption. So there’s little that Americans, with a straight face, can offer the rest of the world by way of advice on energy conservation, until we end our own society’s dependence on lavish cooling.
Currently, the biggest increase in energy consumption for cooling is happening in China. The warmer urban areas of China are already becoming thoroughly air-conditioned and sales are brisk in towns and villages. China could surpass the United States as the world’s biggest user of electricity for air-conditioning by 2020.
Consider this: the number of U.S. homes equipped with air conditioning rose from 64 million to 100 million between 1993 and 2009, whereas 50 million air-conditioning units were sold in China in 2010 alone. And it is projected that the number of air-conditioned vehicles in China will reach 100 million in 2015, having more than doubled in just five years.
As urban China, Japan, and the Republic of Korea approach the air-conditioning saturation point, the greatest demand growth in the post-2020 world is expected to occur mostly in South and Southeast Asia. India’s growth will predominate. If we add up the total amount of hot weather experienced by India’s population in an average year (the country’s “person-cooling-degree-days,” or PCDD), it comes to fourteen times the United States’ annual PCDD (and for comparison, China’s PCDD is five times the United States’.) With incomes rising in China and India between now and 2050, more of that demand will be fulfilled year by year – assuming that both countries resolve already-chronic shortfalls in electricity supply.
You can have a tightly sealed building with optimum energy efficiency for air-conditioning, or you can have a highly efficient naturally cooled building, but they wouldn’t be the same building. Although the green-construction industries in the United States, India, and other countries have come up with compromise designs that can shift between natural and artificial cooling, they are optimum for neither.
The greenhouse impact of air-conditioning comes mostly from the emissions from electricity generation to power it. But refrigerants that escape from air-conditioning systems are powerful greenhouse gases themselves. The accumulated climate impact of both the fossil carbon and refrigerants released annually to run building and vehicle air-conditioners in the United States is equivalent to 600 million tons of carbon dioxide –exceeding the impact of our entire construction industry, including the production of building materials. Similarly, the predicted global expansion of air-conditioning would mean several billion tons’ worth of warming per year in coming decades.
According to a recent forecast by Guus Velders of the Netherlands’ National Institute for Public Health and the Environment and his colleagues, refrigerants that accumulate in the atmosphere between now and 2050 will add another 14 to 27 percent to the increased warming caused by carbon dioxide emissions from all sources. Recent years, therefore, have seen a research stampede to find refrigerants with lighter greenhouse potential. Several promising candidates have been discovered only to be discarded on the basis of flammability, toxicity, ozone depletion, or other problems. None of the remaining prospects is ideal in all respects. One important consideration is efficiency. A refrigerant that has lower direct greenhouse potential than those currently used but that exchanges heat less efficiently causing an air-conditioner to consume more electricity for the same amount of cooling could have a larger total climate impact.