Global efforts to cut air pollution will not speed up the process of global warming, scientists have concluded.
The study, published in the journal Nature, begins by saying that scientists have long worried that air pollution may have been acting as a â€˜brakeâ€™ on the heating of the atmosphere because pollution particles form clouds with more water droplets, meaning they reflect more of the sunâ€™s energy back into space, accelerating global warming.
However, the research which was carried out at the University of Reading has shown air pollution affects different clouds in different ways. They found that some clouds get thicker, others become thinner, meaning pollution is unlikely to offset more than half of greenhouse gas warming.
For the study, the researchers from the University of Reading scoured the world for clouds formed over areas of pollution using near-infrared satellite images. Clouds affected by pollution appear â€˜brighterâ€™ in these images.
The scientists located hundreds of polluted clouds around the world, produced by tiny pollution particles from sources such as volcanoes, cities, ships, factories and wildfires.
They then analysed whether changes to clouds simulated by climate models are accurate, in order to better predict future climate change.
They found that air pollution affects different clouds in different ways. Some clouds get thicker, others become thinner, meaning pollution is unlikely to offset more than half of greenhouse gas warming.
Dr Nicolas Bellouin, study co-author from the University of Reading said: ‘The fear that reducing air pollution could lead to a spike in global warming has been a lingering concern for climate scientists. What if our efforts to clean up the air actually meant we make global warming worse?
‘Our study provides assurances that polluted air has a limited ability to prevent the atmosphere from heating up, in addition to being bad for peopleâ€™s health.
‘There is now one less excuse for us not to cut emissions of both air pollution and greenhouse gases, or we will continue to see temperature rises that put people and the natural world in danger.
‘In any case, a small temperature rise resulting from cutting pollution is a price very much worth paying to prevent greater, long-term harm caused by greenhouse gases.’
Earlier this week, the United Nations Environment Programme (UN Environment) and the Climate and Clean Air Coalition launched a new â€˜Clean Air Initiativeâ€™, which calls on governments around the world to â€˜align climate change and air pollution policiesâ€™ by 2030.
In a statement, the coalition says climate change and air pollution are â€˜closely linkedâ€™ because the main driver of climate change, fossil fuel combustion, also contributes about two-thirds of outdoor air pollution.
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