TORONTO -- A new study suggests that if countries make their climate change targets more ambitious, millions of lives could be saved.

The study, published in a special issue of The Lancet Planetary Health journal, says modelling suggests that “millions of lives could be saved annually” by the year 2040 if countries raise their climate ambitions and adopt policies consistent with the Paris Agreement.

The Paris Agreement is the international treaty on climate change that was adopted by 196 signees in 2015 and came into force in 2016. Its goal is to limit global warming to well below 2 C, preferably 1.5 C, above pre-industrial levels.

The study examined nine countries that represent 50 per cent of the world’s population and 70 per cent of global emissions: Brazil, China, India, Germany, Indonesia, Nigeria, South Africa, the U.K. and the U.S.

Researchers' modelling suggested that adopting policies consistent with achieving the Paris Agreement targets could “save 6.4 million lives due to better diet, 1.6 million lives due to cleaner air and 2.1 million lives due to increased exercise, per year,” across the nine countries.

Ahead of the UN Climate Change Conference in Glasgow in November, countries that have signed the Paris Agreement are updating and revising their “nationally determined contributions” or NDCs, colloquially known as “climate plans,” as current global NDCs are not strong enough to reach the Paris Agreement’s targets.

“We chose to do this study to look at the potential implications to health if countries were to adopt policies aligned with the Paris Agreement commitment,” said lead study author Dr. Ian Hamilton, executive director of the Lancet Countdown on Health and Climate Change, in an email to CTVNews.ca on Tuesday. 

“We carry a substantial health burden of these greenhouse gas emissions,” he said.

For each of the nine countries considered in the study, researchers estimated emissions generated from several sectors and projected their modelling for the year 2040 using three different NDC or “climate plan” scenarios.

“Our analysis relied on detailed data on fuels used in different sectors (power, transport, houses, industry) from the International Energy Agency, country and city level travel surveys (time spent cycling, driving, walking or on public transport), country level diet surveys (type and quantity of food consumed) and data from the UN Food and Agriculture Organization, and then a detailed database on pollution by different sectors,” Hamilton explained in his email.

The first scenario was the baseline and was calculated using the nine countries' current NDCs, the second scenario was calculated using NDC policies in line with the Paris Agreement, and a third scenario was calculated that added specific health objectives within the parameters of the second scenario.

All nine countries’ modelling suggested that if they complied with the second scenario - the Paris Agreement - it could save 5.8 millions lives due to better diet, 1.3 million lives due to cleaner air and 1.2 million lives due to increased exercise. 

If they adhered to the third scenario, with specific health objectives added to the Paris Agreement-compliant “climate plan,” modelling suggested there could be 462,000 fewer deaths attributed to air pollution, 572,000 fewer deaths attributed to diet and 943,000 fewer deaths attributed to physical inactivity annually. 

“The most important findings are that through well-designed mitigation policies across the energy, built environment, food and agriculture, and transport sectors could result in cleaner air, improved housing, increased physical activity and healthier diets,” Hamilton said. “This would see countries taking actions that have global impacts and local benefits.”

The study also concluded that while the impact of each of the three health metrics – air pollution, diet and physical activity – varied from country to country, all nine of them benefitted the most in their modelling from dietary improvements under the Paris Agreement-compliant scenario, which abides by a “flexitarian diet.”

A “flexitarian diet” is usually accompanied by a reduction of red meat consumption and processed food, and greater intake of fruits and vegetables. 

“We know these health benefits would also offer economic benefits in the form of reduced healthcare costs and a more productive workforce and wider societal benefits in wellbeing and quality of life,” Hamilton said.

While some countries have strengthened their NDCs since the study was completed, such as China announcing its commitment to achieving carbon neutrality before 2060, and the U.S. under President Joe Biden’s administration promising to commit to net-zero emissions by 2050, the study notes that the world is still not on track to meet the goals of the Paris Agreement, and will “still face two and half degrees Centigrade of warming by the end of the century.”

Hamilton called the study’s findings “stark” in a press release, and told CTVNews.ca that “we really want the message to people and policy makers alike to be that there is evidence to show that meeting the Paris Agreement commitments will be food for our health and that these benefits accumulate to the individuals in the countries taking leadership.” 

Former director-general of the World Health Organization Margaret Chan said in the release that “the report findings therefore provide an important further incentive not only for the world’s leaders to make good on their climate commitments in new NDCs, but also to align environmental and health objectives in COVID-19 recovery plans.”

Hamilton agrees.

“Unless the global COVID-19 economic recovery is aligned with the response to climate change, the world will fail to meet the target laid out in the Paris Agreement, damaging public health in the short and long term,” he said. 

Hamilton said responding to the converging crises of global warming and a global pandemic in a cohesive way could deliver “a triple win - better public health, a sustainable economy and environmental protection.”