Katharine Hayhoe: Since the 1950s, scientists have known about something called "global dimming" -- caused by tiny particles from air pollution (aerosols) that cool the planet by reflecting some of the Sun's energy back to space. They've been offsetting some of the warming from heat-trapping gases for decades. 🧵

Since the 1950s, scientists have known about something called "global dimming" -- caused by tiny particles from air pollution (aerosols) that cool the planet by reflecting some of the Sun's energy back to space. They've been offsetting some of the warming from heat-trapping gases for decades. 🧵

Aerosol pollution caused decades of “global dimming”news.agu.org AGU press contact: Liza Lester, +1 (202) 777-7494, [email protected] (UTC-5:00) ETH Zurich press contact: Peter Rüegg , +41 44 632 45 32, [email protected] (UTC+1:00) Contact information for the rese...

Aerosol forcing is one of the largest uncertainties in the climate system. Depending on the composition of the particles or droplets, they can have either a cooling or a warming effect. Here's a very comprehensive summary published ten years ago, explaining the complex chemistry of these particles.

Aerosols and their Relation to Global Climate and Climate Sensitivitywww.nature.com Atmospheric aerosols from human activity influence climate. Uncertainties in the understanding of their effects limit our knowledge about climate change.

However, scientists have known for a long time that the net effect of cleaning up our act will most likely be to remove a cooling effect that's been keeping a partial lid on global warming from heat-trapping gases. This is a summary from seven years ago:

Cleaning Up Air Pollution May Strengthen Global Warmingwww.scientificamerican.com New research is helping quantify just how big that effect might be

And that's exactly what we see happening today. Recent pollution reductions, particularly in extremely dirty shipping emissions, are likely driving at least some of the accelerated warming we've been seeing the last year or two. Read more:

We’ve been accidentally cooling the planet — and it’s about to stopwww.washingtonpost.com The burning of fossil fuels has been cooling the planet while warming it — presenting problems for the future.

So why do we want to reduce air pollution from fossil fuels? Because it kills nearly 22,000 people PER DAY, over 500 of those under the age of five. Overall, pollution of air, soil and water is the leading cause of environmental risk for people and a key contributor to biodiversity loss as well.

Pollution and health: a progress updatewww.thelancet.com The Lancet Commission on pollution and health reported that pollution was responsible for 9 million premature deaths in 2015, making it the world's largest environmental risk factor for disease and pr...

Here's the good news, though. When we cut our carbon emissions through efficiency, electrification, and clean energy, we also cut air pollution! Yet another example of why climate solutions are absolutely essential for our health today and our future tomorrow.

Yes and, I just learned that 0.2-1.3C of warming is masked by air pollution so we must must must reduce non-co2 emissions also at the same time because that will drop the temperature fastest and approximately to the same degree as the masking effect. (pls translate to Heyhoe-style comms) :)

And noise pollution.

22k per day globally?

Yes. Over 8 million a year from air pollution from fossil fuels alone. There are also millions from indoor air pollution in low income countries where people don’t have stoves, and more from water and soil pollution as well. Then, there’s the direct impacts of climate change on health …

Fossil fuel air pollution responsible for 1 in 5 deaths worldwidewww.hsph.harvard.edu New research finds that deaths from fossil fuel emissions are higher than previously thought—more than 8 million people per year, worldwide.

great. we gotta rip up this concrete

Great information! Thank you taking the time to put this together.

I first heard of global dimming when researchers got a chance to measure temps during the 3 days airplanes grounded after 9/11. It made me aware of how much contrails contribute to cloud cover and how less sunlight contributes to people’s worsening emotional health individually & on a global scale.

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