This story was originally published by the Guardian and is reproduced here as part of the Climate Desk collaboration.

Doctors and medical professionals from around the globe have called on world leaders to ensure a green recovery from the coronavirus crisis that takes account of air pollution and climate breakdown.

More than 200 organizations representing at least 40 million health workers — making up about half of the global medical workforce — have signed an open letter to the G20 leaders and their chief medical advisers, pointing to the 7 million premature deaths to which air pollution contributes each year around the world.

Chief medical officers and chief scientific advisers must be directly involved in designing the stimulus packages now underway, the letter urges, in order to ensure they include considerations of public health and environmental concerns. They say public health systems should be strengthened, and they warn of how environmental degradation could help to unleash future diseases.

The signatories also want reforms to fossil fuel subsidies, with public support shifted towards renewable energy, which they say would make for cleaner air, cut greenhouse gas emissions, and help to spur economic growth of nearly $100 trillion in the next three decades.

In the letter, the health professionals link air pollution and fragile public health systems with the impacts of the virus, saying air pollution “was already weakening our bodies,” exacerbating the impact of the disease.

“We have witnessed first-hand how fragile communities can be when their health, food security, and freedom to work are interrupted by a common threat. The layers of this ongoing tragedy are many and magnified by inequality and under-investment in public health systems. We have witnessed death, disease, and mental distress at levels not seen for decades,” they write.

Better preparation could have reduced the impacts from the COVID-19 pandemic, according to the letter. “We must learn from these mistakes and come back stronger, healthier, and more resilient,” they write.

Studies have suggested that air pollution may play a role in worsening COVID-19 symptoms or increasing mortality, though scientists also say it is too early to draw hard conclusions about the full impacts. The clearing skies that have accompanied lockdown in many countries are under threat, however, as industrial activity resumes without new safeguards.

Last week a comprehensive study found daily carbon dioxide emissions around the world had fallen by about 17 percent as a result of the lockdowns, and that if normal activity resumed there would be only about a 4 percent fall for the full year, compared with last year. Such a fall would make little difference in the climate crisis.

Some countries are considering a green recovery from the crisis by attaching stern conditions to any bailouts for fossil fuel-dependent industries, such as aviation, and by pumping money into infrastructure that reduces greenhouse gases, from broadband for remote working to better cycle lanes and electric vehicle charging points. A recent study from Oxford University found this would yield more jobs and a better return on public investment than returning to business as usual.

“Health professionals are at the frontlines of this emergency, and we are seeing the immense loss of lives because of acting too late,” said Miguel Jorge, the president of the World Medical Association. “We know now more than ever that healthy lives depend on a healthy planet. As we walk on the road to recovery, we need to build a system that will protect us from further damage. We need a healthy and green recovery.”

Health professionals are concerned that the world will resume its unhealthy practices as the immediate impacts of the coronavirus fade, without learning the lessons needed to put us on a healthier path that would reduce the likelihood of such devastating pandemics in future, as well as reducing illness from other causes and staving off climate breakdown.

“COVID-19 has forced the world to pause and take stock, providing us with a unique opportunity to make changes that will benefit the planet and all the people on it,” said Annette Kennedy, president of the International Council of Nurses. “Climate change poses an imminent and serious threat to the health of the world’s population. We are calling on governments to make sure that pollution levels do not return to previous levels, so that our children and grandchildren will be able to grow up healthily in a livable and sustainable climate. Only by investing in both healthcare and the environment can we create a sustainable future.”

The signatories include the World Medical Association, the International Council of Nurses, the Commonwealth Nurses and Midwives Federation, the World Organization of Family Doctors, and the World Federation of Public Health Associations, as well as thousands of individual health professionals.

The letter has been sent to all G20 leaders, including Boris Johnson, Angela Merkel, and Xi Jinping, who are under pressure to approve a green recovery, as well as those who have been criticized for a lax approach to the crisis or for using it to weaken environmental protections, including Donald Trump, Vladimir Putin, and Jair Bolsonaro.