We are delighted to introduce you to

We are delighted to introduce you to the inaugural issue of , a journal that will join and to provide a third pillar in an open-access programme covering the interplay between health and the determinants of health in our living and physical world. What is planetary health? And what kind of science will this new journal be seeking? In The Rockefeller Foundation– Commission on Planetary Health, planetary health was defined as the health of human civilisations and the natural systems on which they depend. To explain this idea in simpler terms we need to think of human beings as a powerful and growing force behind the environmental change that we are witnessing today. Alterations to climate, water, land and ecosystems are challenging all life on our planet, with serious implications for human health. The way we think about the planet needs to be revised, as does the approach we take in interacting with it.
The Paris Agreement was a major political step towards reducing the risks of climate change; however, even if the agreed reductions in greenhouse gas emissions are fully implemented, the global average temperature will still have increased by about 3°C above preindustrial levels by the end of the century. Deeper cuts are needed for the achievement of the long-term goal of keeping the increase to well below 2°C. An obvious rationale for action is the imperative to reduce the risks to health from climate change, but in an era when powerful interests seek to d-amphetamine doubt on climate change science, major ancillary near-term benefits (co-benefits) of climate action provide added justification for policies to cut greenhouse gas emissions. Health co-benefits can arise through several pathways, including through reduced air pollution, increased physical activity, and dietary change. The International Energy Agency suggested that a 7% increase in investment to achieve a “Clean Air Scenario” could result in saving 3 million premature deaths worldwide in 2040, provide energy access for all, and lead to a peak in carbon dioxide emissions in 2020. The shows the sources of major primary air pollutants. In China, under the same scenario, mean life expectancy is increased by 15 months in 2040, relative to today. Although the benefits are larger in more highly polluted countries, they can be substantial even in developed nations. For example, in the USA, clean energy policies consistent with warming of 2°C could prevent 175 000 premature deaths by 2030, and subsequently 22 000 (95% CI 11 000–96 000) annually after 2030, with clean transportation contributing additional benefits. Global average marginal co-benefits of avoided mortality have been valued between US$50–380 per tonne of carbon dioxide, which exceed marginal abatement costs in 2030 and 2050. Global fossil fuel subsidies are estimated to total around $5·3 trillion annually, largely as a result of a failure to account for the costs of air pollution and climate change. Removing these subsidies and implementing carbon taxes could, if properly designed, improve health, reduce greenhouse gas emissions, redistribute wealth, and stimulate employment. Policies to reduce short-lived climate pollutants, particularly black carbon, a component of fine particulate air pollution arising from incomplete combustion, could result in 0·7–4·7 million avoided premature deaths annually from reduced ambient air pollution alone. Reductions in methane, another short-lived climate pollutant and a precursor of tropospheric ozone, which damages crop growth, could increase annual crop yields by 30–135 million tonnes due to ozone reductions in 2030 and beyond. A 2016 systematic review has shown the potential to reduce greenhouse gas emissions, together with land and water use, by shifting present dietary intakes to environmentally more sustainable healthy diets, suggesting that median reductions of 20–30% across these indicators are possible in high-income settings, with modest reductions in all-cause mortality risk. Reductions in environmental footprints were generally proportional to the magnitude of animal-based food restriction. The greatest per-calorie environmental impacts were for ruminant meat, followed by other animal products, and lowest for many plant-based foods. Additional evidence from low-income settings is needed.