Reaching net zero greenhouse gas emissions in England and Wales by 2050 will lead to an extra 2m years of life, a study suggests.

The UK is legally committed to hitting net zero by 2050. Many of the proposed policies will reduce harmful environmental factors such as air pollution, and encourage healthy behaviours including diet and exercise, but this is the first time researchers have comprehensively modelled how net zero will affect health.

Implementing net zero policies will result in “substantial reductions in mortality”, according to the study published in the Lancet Planetary Health journal.

And the combination of policies will lead to at least 2m additional years lived across the population of England and Wales by 2050, researchers found.

“Our modelling confirms that there are significant health benefits to implementing net zero policies,” said Dr James Milner, of the London School of Hygiene & Tropical Medicine, which led the research. “Not only are these policies essential for mitigating climate change, they also make us healthier.”

The study measured health benefits by looking at reductions in mortality alone. However, as well as driving reductions in mortality, evidence suggests net zero policies may also result in people living with fewer health conditions.

Retrofitting homes with insulation would account for 836,000 out of the 2m additional years lived, as long as ventilation measures are provided for upgraded homes, the study suggests.

“The central role played by retrofitting homes with insulation in delivering these health benefits is particularly striking,” said Milner.

“Housing in England and Wales is poorly insulated compared to other countries, so actions taken towards improving home energy efficiency prove particularly beneficial to reducing carbon emissions and improving health.

“The energy and cost of living crises this winter have provided a long list of reasons for the UK to adopt an ambitious insulation policy; our study adds better health to that list.”

Researchers looked at six net zero policies in four different sectors – electricity supply, transport, housing and food. They used modelling to estimate how these policies affect health, taking into account how much they reduce air pollution, make diets healthier and increase exercise.

The researchers considered two scenarios – a balanced pathway in which a 60% reduction in emissions was achieved by 2035 and a widespread engagement pathway in which behaviour changed more rapidly with regards to diet and travel choices.

They measured the policies’ impact on health by looking at the number of additional years people would live across the whole population.

After retrofitting homes with insulation, the second and third largest policies to benefit health were switching to renewable energy to power homes and reducing red meat consumption – resulting in 657,000 and 412,000 life years gained respectively.

Replacing car journeys with walking or cycling resulted in 125,000 life years gained, while switching to renewable energy for electricity generation resulted in 46,000 life years gained. Switching to renewable energy for transport saw 30,000 life years gained.

The balanced pathway led to 2m additional years lived across the population of England and Wales. The health benefits were even better under the widespread engagement pathway, totalling nearly 2.5m life years gained by 2050.

“If we move faster in adopting more environmentally friendly diets and active ways of travelling, the health benefits will be even greater,” said Milner.

The researchers pointed out several limitations of their study. But they also said the results are likely to underestimate the health benefits of net zero policies.

That is because they were unable to model all the potential health benefits, they explained – for instance, reductions in agricultural air pollution and less nitrogen dioxide pollution from transport.

The researchers were also unable to capture the benefits of other countries implementing their net zero policies on the population of England and Wales, which is likely to reduce air pollution coming from continental Europe, for example.

Writing in the Lancet Planetary Health journal, the researchers concluded: “Reaching net zero greenhouse gas emissions is likely to lead to substantial benefits for public health in England and Wales, with the cumulative net benefits being correspondingly greater with a pathway that entails faster and more ambitious changes, especially in physical activity and diets.”