Extra investments to control deadly pollutants like smog and soot could cut worldwide deaths from air pollution in half in a few decades and end the growth of global warming emissions in just a few years, international experts declared on Monday.
In its first report ever to examine the links between these twin goals, the authoritative International Energy Agency said the solutions go "hand-in-hand."
With a 7 percent increase in energy-related investment, it said, the world could cut air-pollution mortality from about 6.5 million today to 3.3 million in 2040. And the changes would bring about a peak in CO2 emissions by 2020, it said.
Along with spending on pollution control equipment, the keys, it said, are energy efficiency and the use of renewables like wind and solar.
The report marks a new movement among those who favor the long-term goal of fighting global warming toward an equal and more immediate concern—protecting the health of the world.
"Clean air is a basic human right that most of the world's population lacks," said Fatih Birol, IEA's executive director in a statement. "No country—rich or poor—can claim that the task of tackling air pollution is complete."
The effects of air pollution are greatest in developing countries in Asia where there is a high reliance on coal for power generation and in sub-Saharan Africa, where inefficient burning of biomass accounts for more than half of its air pollution.
Eighty percent of the global population living in cities that monitor pollution levels are breathing air considered unhealthy by the World Health Organization.
More than half of all Americans still breathe polluted air due to high ozone and particulate matter, according to a report published earlier this year by the American Lung Association.
The life expectancy of people living in London is cut short by approximately 16 months due to elevated levels of nitrogen oxide, according to a report published in December by the London-based think tank Policy Exchange.
The IEA assessment outlines a Clean Air Scenario where an additional $4.8 trillion in pollution control technologies, renewable energy and energy efficiency measures is invested worldwide between now and 2040. The investment would include making clean cooking facilities available to an additional 1.8 billion people worldwide.
The $4.8 trillion cost represents an additional 7 percent on top of energy spending plans already announced by the world's nations, including the pledges to reduce carbon dioxide emissions that they made under the new Paris climate treaty. (The IEA calls this baseline its "New Policies Scenario" to distinguish it from business as usual.)
The alternative Clean Air Scenario detailed in the report would result in a drop of more than 50 percent in global emissions of sulfur dioxide and nitrogen oxides and a nearly 75 percent reduction in harmful particulate matter emissions by 2040.
Air pollution reductions would be greatest in developing countries. The 60 percent of India's population currently exposed to air with a high concentration of fine particles would, for example, fall to less than 20 percent, according to the report.
"Implementing the IEA strategy in the Clean Air Scenario can push energy-related pollution levels into a steep decline in all countries," Birol said.
"It can also deliver universal access to modern energy, a rapid peak and decline in global greenhouse-gas emissions and lower fossil-fuel import bills in many countries."
The Clean Air Scenario would result in a peak of global carbon dioxide emissions from the energy sector by 2020. Pledges made in Paris, by contrast, would allow CO2 emissions to increase until at least 2040. Additional investments and policies beyond the IEA's Clean Air Scenario would be required to limit warming to the global goal of no more than 2 degrees Celsius.
Carbon dioxide emissions in China may have already peaked in part because the country has made it a priority to reduce air pollution, which results in the premature death of thousands of people in the country each day.
A desire to reduce air pollution in India, which along with China accounts for more than half of all air pollution related deaths worldwide, could drive similar emissions reductions.
"It is clear that India needs an aggressive shift to clean energy now," Sunil Dahiya, climate and energy campaigner for Greenpeace India, said in a statement. "This is the only way to keep our air quality within breathable limits."