Dialogues surrounding environmental sustainability tend to conflate reducing pollution with stopping global warming. After all, greenhouse gases trap heat in the atmosphere and other emissions create holes in the ozone layer. However, not all pollutants have a warming effect. In fact, trying to remove some of the most dangerous air pollution from the atmosphere could actually worsen global warming.
The cooling effect of aerosols
While greenhouse gases like carbon dioxide trap heat, aerosols like sulfates are heavier particles that reflect sunlight back into space. Thus, the heavy smog around urban areas is actually often cooling regions down by blocking out sunlight.
When cities say they plan to clean up smog and pollution, they are often targeting these visible sulfates. While greenhouse gases stay in the atmosphere for a long time after being emitted, sulfates tend to fall back to Earth since they are heavier. That means that stopping emissions right now could significantly lower the amount of sulfates in the air while not having a huge effect on the decades worth of greenhouse gases in the atmosphere.
Problematically, scientists from the Center for International Climate Research predict that stopping all air pollution could increase temperatures by one-half to one degree. The cooling effect of aerosols is so significant that some scientists have proposed releasing large quantities of aerosols into the atmosphere to cool the Earth.
Current dangers of aerosols
Despite the cooling effect of aerosols, they are still one of the main types of air pollution and pose an urgent threat. Scientists estimate that air pollution has caused over 7 million premature deaths around the world.
In the U.S., North Carolina saw a significant decrease in respiratory disease-related deaths after air pollution regulation laws passed in 2002. Air pollution has also been linked to a number of other diseases. Many toxic pollutants can cause cardiovascular diseases as well as some forms of cancer. A recent study conducted at the University of Chicago found that air pollution is significantly linked to mental disorders. Scientists found that poor air quality caused up to a 27% increase in bipolar disorder.
But there’s an important Catch-22
Removing sulfates and other dangerous aerosols from the atmosphere could save millions of lives around the globe. However, with climate change being so drastic already, increasing temperatures by half to one degree could spell disaster.
In any case, countries are already moving forward with air-pollution cleaning initiatives. When it comes to galvanizing sustainable action, countries are often prioritizing short-term gains. Stopping life-threatening air pollution is a much more popular position than preventing global warming in many areas. Of course, it won’t vanish overnight and current cleaning efforts won’t increase global temperatures by too much.
Furthermore, in the long run, removing air pollution is definitely beneficial for stopping climate change. Not only do greenhouse gases worsen global warming, but heavier aerosols also prevent solar panels from working at full efficiency.