These positive examples in recent years must not mask the dangerous consequences of failing to meet the Paris Agreement, the past two decades of relative inaction, the economies and sectors currently lagging behind, and the enormity of the task ahead, which leave achieving the Agreement's aims in a precarious position. Indeed, much of the data presented should serve as a wake-up call to national governments, businesses, civil society, and the health profession. However, as this report demonstrates, the world has already begun to embark on a path to a lowcarbon and healthier world. Whilst the pace of action must greatly accelerate, the direction of travel is set.

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. Adaptation, planning, and resilience for health 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 Panel 1: Progress towards the recommendations of the 2015 Lancet Commission on health and climate change In 2015, the Lancet Commission made ten policy recommendations. Of these ten recommendations, the Lancet Countdown is measuring progress on the following: Recommendation 1: invest in climate change and public health research Since 2007, the number of published articles on health and climate change in scientific journals has increased by 182% (indicator 5.2). Recommendation 2: scale up financing for climate-resilient health systems Spending on direct health adaptation as a proportion of total adaptation spending increased in 2017 to 4•8% (£11•68 billion), which is an increase in absolute and relative terms from the previous year (indicator 2.7). Health-related adaptation spending (including disaster response and food and agriculture) was estimated at 15•2% of total adaptation spend. Although this national-level spending is increasing, climate financing for mitigation and adaptation remains well below the US$100 billion per year committed in the Paris Agreement (indicator 2.8). Recommendation 3: phase out coal-fired power Coal consumption remains high, but continued to decline in 2017, a trend which is largely driven by China's decreased reliance and continued investment in renewable energy (indicators 3.2 and 3.3). The Powering Past Coal Alliance (an alliance of 23 countries including the UK, Italy, Canada, and France) was launched at the 23rd Conference of the Parties to the UN Framework Convention on Climate Change (UNFCCC) in December, 2017 (COP23), committing to phase out coal use by 2030 or earlier. Recommendation 4: encourage city-level low-carbon transition to reduce urban pollution In 2017, a new milestone was reached, with more than 2 million electric vehicles on the road, and with global per-capita electricity consumption for road transport increasing by 13% from 2013 to 2015 (indicator 3.6). C...

BackgroundIncreasing active travel (primarily walking and cycling) has been widely advocated for reducing obesity levels and achieving other population health benefits. However, the strength of evidence underpinning this strategy is unclear. This study aimed to assess the evidence that active travel has significant health benefits.MethodsThe study design was a systematic review of (i) non-randomised and randomised controlled trials, and (ii) prospective observational studies examining either (a) the effects of interventions to promote active travel or (b) the association between active travel and health outcomes. Reports of studies were identified by searching 11 electronic databases, websites, reference lists and papers identified by experts in the field. Prospective observational and intervention studies measuring any health outcome of active travel in the general population were included. Studies of patient groups were excluded.ResultsTwenty-four studies from 12 countries were included, of which six were studies conducted with children. Five studies evaluated active travel interventions. Nineteen were prospective cohort studies which did not evaluate the impact of a specific intervention. No studies were identified with obesity as an outcome in adults; one of five prospective cohort studies in children found an association between obesity and active travel. Small positive effects on other health outcomes were found in five intervention studies, but these were all at risk of selection bias. Modest benefits for other health outcomes were identified in five prospective studies. There is suggestive evidence that active travel may have a positive effect on diabetes prevention, which may be an important area for future research.ConclusionsActive travel may have positive effects on health outcomes, but there is little robust evidence to date of the effectiveness of active transport interventions for reducing obesity. Future evaluations of such interventions should include an assessment of their impacts on obesity and other health outcomes.

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Objective To quantify the effect of the introduction of 20 mph (32 km an hour) traffic speed zones on road collisions, injuries, and fatalities in London.Design Observational study based on analysis of geographically coded police data on road casualties, 1986-2006. Analyses were made of longitudinal changes in counts of road injuries within each of 119 029 road segments with at least one casualty with conditional fixed effects Poisson models. Estimates of the effect of introducing 20 mph zones on casualties within those zones and in adjacent areas were adjusted for the underlying downward trend in traffic casualties.Setting London.Main outcome measures All casualties from road collisions; those killed and seriously injured (KSI).Results The introduction of 20 mph zones was associated with a 41.9% (95% confidence interval 36.0% to 47.8%) reduction in road casualties, after adjustment for underlying time trends. The percentage reduction was greatest in younger children and greater for the category of killed or seriously injured casualties than for minor injuries. There was no evidence of casualty migration to areas adjacent to 20 mph zones, where casualties also fell slightly by an average of 8.0% (4.4% to 11.5%).Conclusions 20 mph zones are effective measures for reducing road injuries and deaths.

BackgroundMany local authorities in England and Wales have reduced street lighting at night to save money and reduce carbon emissions. There is no evidence to date on whether these reductions impact on public health. We quantified the effect of 4 street lighting adaptation strategies (switch off, part-night lighting, dimming and white light) on casualties and crime in England and Wales.MethodsObservational study based on analysis of geographically coded police data on road traffic collisions and crime in 62 local authorities. Conditional Poisson models were used to analyse longitudinal changes in the counts of night-time collisions occurring on affected roads during 2000–2013, and crime within census Middle Super Output Areas during 2010–2013. Effect estimates were adjusted for regional temporal trends in casualties and crime.ResultsThere was no evidence that any street lighting adaptation strategy was associated with a change in collisions at night. There was significant statistical heterogeneity in the effects on crime estimated at police force level. Overall, there was no evidence for an association between the aggregate count of crime and switch off (RR 0.11; 95% CI 0.01 to 2.75) or part-night lighting (RR 0.96; 95% CI 0.86 to 1.06). There was weak evidence for a reduction in the aggregate count of crime and dimming (RR 0.84; 95% CI 0.70 to 1.02) and white light (RR 0.89; 95% CI 0.77 to 1.03).ConclusionsThis study found little evidence of harmful effects of switch off, part-night lighting, dimming, or changes to white light/LEDs on road collisions or crime in England and Wales.

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Much recent public health research has emphasised the health impacts for young people of 'active travel' modes, typically defined as walking and cycling. Less research has focused on public transport modes. Drawing on qualitative data, we examine the links between bus travel and wellbeing in London, where young people currently have free bus travel. Our findings indicate that bus travel can be both a physically and socially active experience for young people. We suggest a more nuanced understanding of 'active travel' is now needed, alongside greater attention to urban public transport networks as key sites that impact on important determinants of wellbeing such as independent mobility and social inclusion.