By Ian Roberts
LONDON – Mitigating climate change presents unrivaled opportunities for improving human health and well being. Indeed, policies to reduce greenhouse-gas emissions promise to bring about substantial reductions in heart disease, respiratory illness, cancer, obesity, diabetes, depression, and road deaths and injuries.
These health benefits arise because climate policy necessarily affects two of the most important determinants of human health: nutrition and movement. Although medical professionals increasingly recognize the health benefits of policies to address climate change, they are not widely appreciated by policymakers themselves. The existence of these health benefits implies a dramatic reduction in the net cost of taking strong action to mitigate climate change – which means that failure to understand their importance could have serious environmental consequences.
Recent research has documented the multiple health benefits of reducing greenhouse-gas emissions. Meeting emissions targets in the transport sector would require, alongside reductions in car use, modest increases in walking and cycling. Based on the epidemiological evidence linking physical activity and health, the resulting increase in physical activity would dramatically reduce rates of chronic disease, with around 10-20% less heart disease and stroke, 12-18% less breast cancer, and 8% less dementia.
Sustainable transport would also improve our mental health, with an estimated 6% less depression. There would be additional mental-health benefits from more green spaces, less noise pollution, and greater physical fitness.
Reducing livestock production in order to limit cattle-related methane emissions and deforestation – significant factors contributing to climate change – would also improve human health. Fewer livestock would mean fewer animal products in our diet, which would reduce our consum1ption of harmful saturated fats, leading to a 30% decline in heart disease. Reducing meat consumption should reduce rates of colorectal cancer as well – the second most common type in men, after lung cancer.
By improving diet and raising levels of physical activity, policies to mitigate climate change would result in a dramatic cut in rates of diseases that mean premature death and disability for hundreds of millions of people worldwide. They would also reduce population fatness. More than a billion adults are overweight and 300 million are obese, including more than one-third of the US population. And British government scientists predict that the United Kingdom will be “a predominantly obese society” by 2050.
Indeed, if current trends continue, by 2050, nine in ten adults in many developed countries will be overweight or obese. In middle-income countries, too, average body mass index (BMI) is rising steadily. This will have a serious impact on health and well being, increasing the risk of diabetes, heart disease, stroke, and cancer.
But developing countries are also at risk. Mexico, for example, is second only to the US in terms of the prevalence of obesity. The increase in diabetes as a result of population fattening is causing an epidemic of chronic kidney disease in a country where only one in four can expect to receive treatment.
The experience of Cuba in the 1990’s confirms the health effects of reducing fossil-fuel consumption. During the Cuban energy crisis that followed the cut-off of subsidized Soviet supplies, the proportion of adults who were physically active more than doubled. The population’s average BMI fell by 1.5 units, with a halving in the prevalence of obesity, from 14% to 7%. Deaths from diabetes fell by 51%, from heart disease by 35%, and from stroke by 20%.
Moreover, there would be less hunger in a de-carbonized world. In April 2008, Evo Morales, the president of poor and increasingly hungry Bolivia, pleaded for “la vida primero, los autos segundos” (life first, cars second), exhorting the wealthy world to stop burning food every time they drive – a reference to Western governments’ policies on bio-fuels.
But car use and food prices were linked long before bio-fuel policies. Car use drives up food prices, because oil is a key agricultural input. Reducing oil use in the transport sector is essential to preventing starvation in poor countries. Until agriculture unshackles itself from dependence on oil, gas tanks in rich countries and stomachs in poor countries will be competing to be filled. Eating fewer animal products would reduce food prices as well, because cattle are fed on grain.
Other policies aimed at mitigating climate change also have positive effects on health. Insulating homes in high-income countries in order to save energy would prevent cold-related deaths. Likewise, use of fuel-efficient cooking stoves in poor countries would reduce the number of children – currently around one million per year – who die from respiratory infections caused or worsened by the burning of solid fuels.
A de-carbonization programme that cuts across all the major areas of energy use, combined with reduced consumption of animal products, would create substantial benefits for human health and welfare. As negotiators and policymakers debate the costs of mitigating climate change, they cannot afford to overlook these benefits’ immense value.
