The 2015 Lancet Commission on Health and Climate Change was published on 23 June. A previous commission, established jointly by The Lancet and University College London, described climate change as “the biggest global health threat of the 21st century.” While the 2015 report recommends practical steps to be taken by national and international administrations, it also brings into sharper focus two components that cannot be ignored if a sustainable global solution is to be found to a so-far intractable global problem.

The first is the increasing evidence that a reduction in greenhouse gases leads to health benefits, and therefore a reduction in healthcare costs. These co-benefits include reductions in respiratory illness, road accidents, obesity, and stroke. The 2015 commission therefore moves from the familiar reiteration of the damage to health from global warming to framing a solution. It boldly states that “tackling climate change could be the greatest global opportunity of the 21st century.”

Secondly, a new emphasis is given to the connection between climate change and poverty. The poorest, the elderly, young children, and those with disability are more vulnerable to the effects of climate change. These impacts are unevenly distributed, with greater risks in less developed countries. It therefore follows that a growth in affordable renewable energy will bring huge benefits to the economically disadvantaged. The Commission draws attention to the reduction in fuel poverty that such increased energy efficiency delivers, since low-income families have to spend a larger proportion of their income to heat or cool their homes.

Countries with the highest growth in population are more exposed to the ravages of climate change. This brings us to another recent publication—Pope Frances’ Encyclical Letter “Laudato Si.” While the letter asks Catholics to “look for solutions not only in technology but in a change of humanity,” it relies heavily on science to make its case. Health problems caused by atmospheric pollutants, the acidification of soil and water, fertilizers, insecticides, fungicides and herbicides are all cited, as are the “hundreds of millions of tons of waste” from homes, businesses, construction sites, and from clinical, electronic and industrial sources. The earth, says the Pope, “is beginning to look more and more like an immense pile of filth”. He identifies rises in sea level, extreme weather events and the destruction of ecosystems and reduced biodiversity as major consequences.

While the Lancet Commission identifies the poorest in society as especially vulnerable, this economic vulnerability is expressed in the Encyclical as resulting from “their means of subsistence (being) largely dependent on natural reserves and ecosystemic services such as agriculture, fishing and forestry.” The two documents overlap in identifying the potential for technological change to widen the gap between rich and poor. By explicitly raising questions of justice, the Pope calls in aid human rights law, an instrument that to date has received little attention in relation to climate change. Such legislation, which requires countries to provide their citizens with the highest attainable standards of health, has great potential in calling to account those countries that fail to act.

At this point the Pope enters a logical blind alley. For health professionals, the solution to climate change must be securely balanced on the three legs of co-benefits, the social determinants of health, and population control. Without all three being brought into play, the tripod tips over. The Pope declares that “we still have not solved the problem of poverty,” but has to evade and avoid one obvious part of the solution. “Instead of resolving the problems of the poor” he says, “some can only propose a reduction in the birth rate.” He claims, somewhat ineffectually, that “it must .. be recognized that demographic growth is fully compatible with an integral and shared development,” and flatly states that “since everything is interrelated, concern for the protection of nature is also incompatible with the justification of abortion.”

However predictable and inevitable the Catholic church’s position is on population control (one that is ignored by the majority of its adherents), Pope Francis is right to make connections between climate change, poverty, and social inequalities. The fact that he is right to do so is demonstrated by the vacuous response of Jeb Bush (“I don’t get economic policy from my bishops or my cardinals or from my pope.”) and a call from right-wing presidential hopefuls to keep religion out of politics, thereby proving that the Republican Party is an irony-free zone.

We are all understandably disorientated when it comes to seeing our way through the climate change fog. We are encouraged to make small but significant individual changes to our behaviour while watching our governments’ repeated failures to tackle it. While government denial has contributed mightily to a deep sense of drift and helplessness, action at a national and global level is essential if the earth’s temperature is not to be contained. An approach that harnesses our knowledge of health co-benefits, the social determinants of health, and population control can succeed. To date the leadership and vision is sadly absent.

Michael Wilks is a forensic physician and Treasurer of the Climate and Health Council. 

Competing interests: None declared.