The Lancet Countdown: tracking progress on health and climate change was established to provide an independent, global monitoring system dedicated to tracking the health dimensions of the impacts of, and the response to, climate change. The Lancet Countdown tracks 41 indicators across five domains: climate change impacts, exposures, and vulnerability; adaptation, planning, and resilience for health; mitigation actions and health co-benefits; finance and economics; and public and political engagement. This report is the product of a collaboration of 27 leading academic institutions, the UN, and intergovernmental agencies from every continent. The report draws on world-class expertise from climate scientists, ecologists, mathematicians, geographers, engineers, energy, food, livestock, and transport experts, economists, social and political scientists, public health professionals, and doctors. The Lancet Countdown’s work builds on decades of research in this field, and was first proposed in the 2015 Lancet Commission on health and climate change, which documented the human impacts of climate change and provided ten global recommendations to respond to this public health emergency and secure the public health benefits available (panel 1). 1.. Present day changes in heat waves, labour capacity, vector-borne disease, and food security provide early warning of the compounded and overwhelming impact on public health that are expected if temperatures continue to rise. Trends in climate change impacts, exposures, and vulnerabilities show an unacceptably high level of risk for the current and future health of populations across the world. 2.. A lack of progress in reducing emissions and building adaptive capacity threatens both human lives and the viability of the national health systems they depend on, with the potential to disrupt core public health infrastructure and overwhelm health services. 3.. Despite these delays, a number of sectors have seen the beginning of a low-carbon transition, and it is clear that the nature and scale of the response to climate change will be the determining factor in shaping the health of nations for centuries to come. 4.. Ensuring a widespread understanding of climate change as a central public health issue will be crucial in delivering an accelerated response, with the health profession beginning to rise to this challenge. Vulnerability to extremes of heat has steadily risen since 1990 in every region, with 157 million more people exposed to heatwave events in 2017, compared with 2000, and with the average person experiencing an additional 1·4 days of heatwaves per year over the same period (indicators 1.1 and 1.3). For national economies and household budgets, 153 billion hours of labour were lost in 2017 because of heat, an increase of more than 62 billion hours (3·2 billion weeks of work) since 2000 (indicator 1.4). The direct effects of climate change extend beyond heat to include extremes of weather. In 2017, a total of 712 extreme weather events resulted in US$326 billion in economic losses, almost triple the total losses of 2016 (indicator 4.1). Small changes in temperature and precipitation can result in large changes in the suitability for transmission of important vector-borne and water-borne diseases. In 2016, global vectorial capacity for the transmission of the dengue fever virus was the highest on record, rising to 9·1% for Aedes aegypti and 11·1% for Aedes albopictus above the 1950s baseline. Focusing on high-risk areas and diseases, the Baltic region has had a 24% increase in the coastline area suitable for epidemics of Vibrio cholerae, and in 2016, the highlands of sub-Saharan Africa saw a 27·6% rise in the vectorial capacity for the transmission of malaria from the 1950 baseline (indicator 1.8). A proxy of agricultural yield potential shows declines in every region, with 30 countries having downward trends in yields, reversing a decades-long trend of improvement (indicator 1.9.1). Decreasing labour productivity, increased capacity for the transmission of diseases such as dengue fever, malaria, and cholera, and threats to food security provide early warning of compounding negative health and nutrition effects if temperatures continue to rise. Global inertia in adapting to climate change persists, with a mixed response from national governments since the signing of the Paris Agreement in 2015. More than half of global cities surveyed expect climate change to seriously compromise public health infrastructure, either directly, with extremes of weather disrupting crucial services, or indirectly, through the overwhelming of existing services with increased burdens of disease (indicator 2.2). Globally, spending for climate change adaptation remains well below the $100 billion per year commitment made under the Paris Agreement. Within this annual spending, only 3·8% of total development spending committed through formal UN Framework Convention on Climate Change (UNFCCC) mechanisms is dedicated to human health (indicator 2.8). This low investment in adaptive capacity is magnified in specific regions around the world, with only 55% of African countries meeting International Health Regulation core requirements for preparedness for a multihazard public health emergency (indicator 2.3). Multiple examples of stagnated mitigation efforts exist, with a crucial marker of decarbonisation—the carbon intensity of total primary energy supply—remaining unchanged since 1990 (indicator 3.1). A third of the global population, 2·8 billion people, live without access to healthy, clean, and sustainable cooking fuel or technologies, which is the same number of people as in 2000 (indicator 3.4). In the transport sector, per-capita global road-transport fuel use increased by 2% from 2013 to 2015, and cycling comprises less than 10% of total journeys taken in three quarters of a global sample of cities (indicators 3.6 and 3.7). The health burden of such inaction has been immense, with people in more than 90% of cities breathing polluted air that is toxic to their cardiovascular and respiratory health. Indeed, between 2010, and 2016, air pollution concentrations worsened in almost 70% of cities around the globe, particularly in low-income and middle-income countries (LMICs; indicator 3.5.1). In 2015 alone, fine particulate matter (ie, atmospheric particulate matter with a diameter of less than 2·5 μm [PM_2·5]) was responsible for 2·9 million premature deaths, with coal being responsible for more than 460 000 (16%) of these deaths, and with the total death toll (from other causes including particulates and emissions such as nitrogen oxide) being substantially higher (indicator 3.5.2). Of concern, global employment in fossil-fuel extractive industries actually increased by 8% between 2016, and 2017, reversing the strong decline seen since 2011 (indicator 4.4). At a time when national health budgets and health services face a growing epidemic of lifestyle diseases, continued delay in unlocking the potential health co-benefits of climate change mitigation is short-sighted and damaging for human health. Despite this stagnation, progress in the power generation and transport sectors provide some cause for optimism, with many positive trends being observed in the 2017 report, and which continue in the present 2018 report. Notably, coal use continues to decline (indicator 3.2) and more renewable energy was installed in 2017 than energy from fossil fuels (indicator 3.3). However, maintaining the global average temperature rise to well below 2°C necessitates wide-reaching transformations across all sectors of society, including power generation, transport, spatial infrastructure, food and agriculture, and the design of health systems. These transformations, in turn, offer levers to help tackle the root causes of the world’s greatest public health challenges. About 712 climate-related extreme events were responsible for US$326 billion of losses in 2017, almost triple the losses of 2016 (indicator 4.1). Crucially, 99% of the losses in low-income countries remained uninsured. Indicators of investment in the low-carbon economy show that the transition is already underway, with continued growth in investment in zero-carbon energy, and growing numbers of people employed in renewable energy sectors (indicators 4.2 and 4.4). Furthermore, investment in new coal capacity in 2017, was at its lowest in at least 10 years, with 2015 potentially marking a peak in coal investment. Correspondingly, global subsidies for fossil fuels continued to decrease, and carbon pricing only covers 13·1% of global greenhouse-gas emissions, a number that is expected to increase to more than 20% when planned legislation in China is implemented in late 2018 (indicators 4.6 and 4.7). However, the rise of employment in fossil fuel industries in 2017 reversed a 5 year downward trend, and will be a key indicator to follow closely. A better understanding of the health dimensions of climate change allows for advanced preparedness, increased resilience and adaptation, and a prioritisation of mitigation interventions that protect and promote human wellbeing. To this end, coverage of health and climate change in the media has increased substantially between 2007, and 2017 (indicator 5.1). Following this trend, the number of academic journal articles published on health and climate change has almost tripled over the same period (indicator 5.2). These figures often follow internationally important events, such as the UNFCCC’s Conference of the Parties (COP), along with temporary rises in mentions of health and climate change within the UN General Debate (UNGD; indicator 5.3). The extended heatwaves across the northern hemisphere in the summer of 2018, might prove to be a turning point in public awareness of the seriousness of climate change. 2017 saw a substantial rise in the number of medical and health professional associations actively responding to climate change. In the USA, the US Medical Society Consortium on Health and Climate represents 500 000 physicians. This organisation follows the formation of the UK Health Alliance on Climate Change, which brings together many of the UK’s royal medical and nursing colleges and major health institutions. Organisations like the European Renal Association–European Dialysis and Transplant Association and the UK’s National Health Service (NHS) are committing to reducing the contributions of their clinical practice emissions. The NHS achieved an 11% reduction in emissions between 2007, and 2015. Several health organisations have divested, or are committing to divest, their holdings in fossil fuel companies, including the Royal Australasian College of Physicians, the Canadian Medical Association, the American Public Health Association, and the World Medical Association (indicator 4.5). Given that climate change is the biggest global health threat of the 21st century, responding to this threat, and ensuring this response delivers the health benefits available, is the responsibility of the health profession; indeed, such a transformation will not be possible without it. The 2015 Lancet Commission made ten global recommendations to accelerate the response to climate change and deliver the health benefits this response could offer. A summary of the progress made against these recommendations using the 2018 Lancet Countdown’s indicators is presented in panel 1. Here, global leadership is increasingly provided by China, the EU, and many of the countries that are most vulnerable to climate change.

The Lancet Countdown: tracking progress on health and climate change is an international, multidisciplinary research collaboration between academic institutions and practitioners across the world. It follows on from the work of the 2015 Lancet Commission, which concluded that the response to climate change could be "the greatest global health opportunity of the 21st century". The Lancet Countdown aims to track the health impacts of climate hazards; health resilience and adaptation; health co-benefits of climate change mitigation; economics and finance; and political and broader engagement. These focus areas form the five thematic working groups of the Lancet Countdown and represent different aspects of the complex association between health and climate change. These thematic groups will provide indicators for a global overview of health and climate change; national case studies highlighting countries leading the way or going against the trend; and engagement with a range of stakeholders. The Lancet Countdown ultimately aims to report annually on a series of indicators across these five working groups. This paper outlines the potential indicators and indicator domains to be tracked by the collaboration, with suggestions on the methodologies and datasets available to achieve this end. The proposed indicator domains require further refinement, and mark the beginning of an ongoing consultation process-from November, 2016 to early 2017-to develop these domains, identify key areas not currently covered, and change indicators where necessary. This collaboration will actively seek to engage with existing monitoring processes, such as the UN Sustainable Development Goals and WHO's climate and health country profiles. The indicators will also evolve over time through ongoing collaboration with experts and a range of stakeholders, and be dependent on the emergence of new evidence and knowledge. During the course of its work, the Lancet Countdown will adopt a collaborative and iterative process, which aims to complement existing initiatives, welcome engagement with new partners, and be open to developing new research projects on health and climate change.

In this review of reviews, we overview the current global body of available evidence from structured reviews of epidemiological studies that explore human health outcomes associated with exposure to phthalates (chemical plasticisers commonly found in plastics). We found robust evidence for an association with lower semen quality, neurodevelopment and risk of childhood asthma, and moderate to robust evidence for impact on anogenital distance in boys. We identified moderate evidence for an association between phthalates/metabolites and low birthweight, endometriosis, decreased testosterone, ADHD, Type 2 diabetes and breast/uterine cancer. There was some evidence for other outcomes including anofourchette distance, fetal sex hormones, pre-term birth, lower antral follicle count, reduced oestrodiol, autism, obesity, thyroid function and hearing disorders. We found no reviews of epidemiological human studies on the impact of phthalates from recycled plastics on human health. We recommend that future research should use urine samples as exposure measures, consider confounders in analyses and measure impacts on female reproductive systems. Our findings align with emerging research indicating that health risks can occur at exposure levels below the "safe dose" levels set out by regulators, and are of particular concern given potential additive or synergistic "cocktail effects" of chemicals. This raises important policy and regulatory issues for identifying and controlling plastics and health related impacts and highlights a need for more research into substances of concern entering plastics waste streams via recycling.