The world, especially the northern hemisphere, has been consumed with reducing pollution for over 50 years. Compare the skylines of major cities today with those of 50 years ago and you’ll see a startling difference. A lot of effort has been put into reducing the smog and belching smoke that covered our skies as the post-WWII industrial boom built an economy on manufacturing. Now, our manufacturing is cleaner, and our skies are bluer. You might think that this is a good thing.
Not so fast there, slim. A study published this last Wednesday (April 3), tells us that those cleaner skies contribute to global warming. The multi-authored paper, “Recent reductions in aerosol emissions have increased Earth’s energy imbalance, “calculates that cleaner air could account for 40% of the increased energy warming the planet between 2001 and 2019.” Stop and think about that: FORTY PERCENT. That almost sounds like something we might expect from a conspiracy theory nut. Nope. This is 100% science.
To some extent, this isn’t new news. We’ve known for a while that less pollution has an impact on warming. Pollutants reflect more light into space and increase the number of droplets in clouds, causing them to grow brighter or last longer. That has the net effect of keeping solar energy out of the atmosphere. Kill the pollutants and the solar energy increases. What this new study shows, however, is a significant impact much larger than scientists had expected.
Falling pollution levels aren’t the only factor, though. Pollution has fallen primarily in the northern hemisphere because, duh, that’s where the majority of manufacturing takes place. However, the increase in warming is the same across the planet, including the southern hemisphere where there never was a severe pollution problem. How do we explain this?
The answer reveals a cause-and-effect type of situation. As the planet has grown warmer, snow and ice have melted leaving dark land masses in their place that absorb more light. At the same time, warming also causes low clouds over large bodies of water to dissipate. That blue ocean is a dark blue that, you guessed it, absorbs more heat. This is why we’ve been seeing more active hurricane activity in recent years.
How do we solve this problem? The paper doesn’t say. What it does say is that it takes a long time to see the effect of pollution reduction, decades in fact. We may not yet realize the full impact. Making matters more challenging is that some of the tools used to measure the aerosols are going offline before new ones are in place. There will be years where no one has a clue how much change is taking place, only the knowledge that it’s happening.
No, this isn’t going to cause the world to end any fast. You still have roughly five billion years for that, give or take a century. However, you might want to check the SPF on your sunscreen going forward.
The world, especially the northern hemisphere, has been consumed with reducing pollution for over 50 years. Compare the skylines of major cities today with those of 50 years ago and you’ll see a startling difference. A lot of effort has been put into reducing the smog and belching smoke that covered our skies as the post-WWII industrial boom built an economy on manufacturing. Now, our manufacturing is cleaner, and our skies are bluer. You might think that this is a good thing.
Not so fast there, slim. A study published this last Wednesday (April 3), tells us that those cleaner skies contribute to global warming. The multi-authored paper, “Recent reductions in aerosol emissions have increased Earth’s energy imbalance, “calculates that cleaner air could account for 40% of the increased energy warming the planet between 2001 and 2019.” Stop and think about that: FORTY PERCENT. That almost sounds like something we might expect from a conspiracy theory nut. Nope. This is 100% science.
To some extent, this isn’t new news. We’ve known for a while that less pollution has an impact on warming. Pollutants reflect more light into space and increase the number of droplets in clouds, causing them to grow brighter or last longer. That has the net effect of keeping solar energy out of the atmosphere. Kill the pollutants and the solar energy increases. What this new study shows, however, is a significant impact much larger than scientists had expected.
Falling pollution levels aren’t the only factor, though. Pollution has fallen primarily in the northern hemisphere because, duh, that’s where the majority of manufacturing takes place. However, the increase in warming is the same across the planet, including the southern hemisphere where there never was a severe pollution problem. How do we explain this?
The answer reveals a cause-and-effect type of situation. As the planet has grown warmer, snow and ice have melted leaving dark land masses in their place that absorb more light. At the same time, warming also causes low clouds over large bodies of water to dissipate. That blue ocean is a dark blue that, you guessed it, absorbs more heat. This is why we’ve been seeing more active hurricane activity in recent years.
How do we solve this problem? The paper doesn’t say. What it does say is that it takes a long time to see the effect of pollution reduction, decades in fact. We may not yet realize the full impact. Making matters more challenging is that some of the tools used to measure the aerosols are going offline before new ones are in place. There will be years where no one has a clue how much change is taking place, only the knowledge that it’s happening.
No, this isn’t going to cause the world to end any fast. You still have roughly five billion years for that, give or take a century. However, you might want to check the SPF on your sunscreen going forward.
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