Reducing our use of fossil fuels will lead to a healthier society, says Jonathan A Patz
If we continue to burn fossil fuels at the current rate, the earth will be 1.5°C hotter than pre-industrial levels in 12-34 years, the latest report of the United Nations Intergovernmental Panel on Climate Change says.  This extent of warming would kill 70-90% of our coral reefs and damage terrestrial crops and ecosystems. Climate change also threatens to disrupt public health through exposure to more intense heat waves and storms, air pollution, malnutrition, climate sensitive infectious diseases, and social dislocation. 
The report found that limiting global warming to under 1.5°C—a preferred goal set in the 2015 Paris climate agreement—would require a 45% drop in global net emissions of CO2 by 2030, and “net zero” emissions would need to be achieved by 2050.  So, are we doomed or can we find reasons for optimism?
Though it might seem paradoxical, the global climate crisis gives us an incredible opportunity, particularly regarding our health. Consider the following: the World Health Organization estimates that 7 million people die prematurely every year from air pollution, rates of obesity and chronic diseases are rising dramatically across almost all regions of the world, and physical inactivity from sedentary lifestyles causes an estimated five million deaths a year. [3,4]
The common link to these health challenges is burning fossil fuels, which releases dangerous pollutants such as fine particulates (PM2.5) alongside the greenhouse gases that are heating the planet. So using clean sources of energy (such as wind or the sun) could both reduce climate change and save lives. Recent studies even show health benefits outweighing investment costs of clean energy technology. In the United States, for example, monetised health benefits associated with improved air quality can offset between 26% and 1050% of the cost of low carbon policies5; in other words, health dividends could be up to 10 times greater than the costs of clean energy technology. Of course, health benefits from clean air will be even larger in many highly polluted cities across the globe. [6,7]
What’s the link between fossil fuels and upward trends in obesity and chronic diseases, such as diabetes and heart disease? Many cities, especially in the US, prioritise and set metrics for how fast street networks can move cars instead of focusing on people (California is a notable exception). Herein lie even more opportunities for public health by adopting other modes of transportation, especially those that promote “active transport” by foot or by bicycle. A growing body of evidence shows substantial health benefits from active transport.  In the US, cities with the highest levels of active transport have obesity rates that are 20% lower and diabetes rates that are 23% lower than cities with the lowest levels. Bicycling commuters in Copenhagen have a 39% lower mortality rate than non-cycling commuters, and in Shanghai, China, active travel could reduce colon cancer risk by over 40%. In short, exercise and fitness, along with improved air quality, can enhance health in the urban population.
The urgency of curbing fossil fuel consumption is abundantly clear if we hope to avoid catastrophic disruption of the earth’s climate system. At the same time, accelerating rates of chronic disease are inextricably linked to our use of fossil fuels to generate power and for transportation. Reducing our use of fossil fuels will lead to a healthier, flourishing society. And this change just might be the greatest health advance in our lifetimes.
Jonathan A Patz is professor and John P Holton chair in health and the environment at the University of Wisconsin-Madison, where he also directs the Global Health Institute. Patz co-chaired the health expert panel of the first congressionally mandated US National Assessment on Climate Change and for 15 years served as a lead author for the United Nations Intergovernmental Panel on Climate Change.
Competing interests: None declared.
1 UN Intergovernmental Panel on Climate Change (IPCC). Global Warming of 1.5 °C, an IPCC special report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. Cambridge University Press, 2018, (forthcoming).
2 Patz JA, Frumkin H, Holloway T, Vimont DJ, Haines A. Climate change: challenges and opportunities for global health. JAMA 2014;312:1565–80. PubMed doi:10.1001/jama.2014.13186
3 NCD Risk Factor Collaboration (NCD-RisC). Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19·2 million participants. Lancet 2016;387:1377–96. PubMed doi:10.1016/S0140-6736(16)30054-X
4 Lee IM, Shirona EJ, Lobelo F, Pusha P, Blair SN, Katzmarzyk PT; Lancet Physical Activity Series Working Group. Impact of physical inactivity on the world’s major non-communicable diseases. Lancet 2012;380:219–29. doi:10.1016/S0140-6736(12)61031-9. PubMed
5 Thompson TM, Rausch S, Saari RK, Selin NE. A systems approach to evaluating the air quality co-benefits of US carbon policies. Nat Clim Chang 2014;4:917–23 doi:10.1038/nclimate2342.
6 UK Health Alliance on Climate Change. Moving beyond the air quality crisis. http://www.ukhealthalliance.org/wp-content/uploads/2018/10/Moving-beyond-the-Air-Quality-Crisis-4WEB-29_10-2018-final-1.pdf
7 WHO. Air pollution and child health: prescribing clean air. http://www.who.int/ceh/publications/Advance-copy-Oct24_18150_Air-Pollution-and-Child-Health-merged-compressed.pdf?ua=1