The pre-industrial atmosphere contained more particles, and so brighter clouds, than we previously thought. This is the latest finding of the CLOUD experiment, a collaboration between around 80 scientists at the CERN particle physics lab near Geneva. It changes our understanding of what was in the atmosphere before humans began adding pollution – and what it might be like again in the future.
Most cloud droplets need tiny airborne particles to act as "seeds" for their formation and growth. If a cloud has more of these seeds, and therefore more droplets, it will appear brighter and reflect away more sunlight from the Earth's surface. This in turn can cool the climate. Therefore understanding the number and size of particles in the atmosphere is vital to predicting not only how bright and reflective the planet's clouds are, but what global temperatures will be.
...
The CLOUD experiment at CERN also recently discovered that gases emitted by trees can stick together to make new seeds for clouds in the atmosphere – without needing any help from other pollutants as was previously thought. Scientists had thought that the cloud seeds needed sulphuric acid (often mixed with other compounds) or iodine molecules to stick together to initiate the process.In our new follow-up study, published in PNAS, we worked with other CLOUD scientists to simulate this process in the atmosphere. Our work suggests that even today trees produce a large fraction of cloud seeds over the cleanest forested parts of the world.
More trees means more clouds, which means cooler Earth.
(Score: 2) by tibman on Tuesday October 11 2016, @09:00PM
I read it the opposite way. There use to be more particulates in the air. So fire up that charcoal grill! Or plant a tree. The tree thing seems like a better long-term plan than having to grill out every day rain or shine. I love that the atmosphere is so complicated : )
SN won't survive on lurkers alone. Write comments.
(Score: 2) by The Mighty Buzzard on Tuesday October 11 2016, @09:16PM
Ya, jokes aside I'm a big fan of having trees around. Wood's valuable and I'm rather fond of oxygen and shade in the summer as well.
My rights don't end where your fear begins.
(Score: 3, Informative) by frojack on Tuesday October 11 2016, @10:48PM
There use to be more particulates in the air.
I doubt that interpretation. I think the article conflates two different discoveries.
pre-industrial atmosphere contained more particles, and so brighter clouds, than we previously thought.
and
also recently discovered that gases emitted by trees can stick together to make new seeds
The pre-industrial revolution atmosphere had the smoke from a billion cooking fires for as far back as history records. A little open hearth fire in every tent building and encampment is probably within a few orders of magnitude of automotive pollution of today, and the coal fired industry of the last couple hundred years.
Yet, everyone assumed the industrial revolution sullied pristine skies. The first finding was that this was wrong and we were mistaken, and the rain falling in the earliest of times formed the same way as rain today.
Finding two was that in addition to dust, smoke from natural fires, and early man's fires, and volcanic eruptions, that the trees themselves emit respiration gasses that can stick together to form particles.
There was always particles. Nothing is new here other then a better understanding of the sources.
Yes, it rained while dinosaurs roamed the earth, and yes there was particles in the air before that as well.
No, you are mistaken. I've always had this sig.
(Score: 4, Informative) by captain normal on Wednesday October 12 2016, @04:20AM
"The pre-industrial revolution atmosphere had the smoke from a billion cooking fires for as far back as history records."
Actually the human population only reached one billion around 1804. Got to 2 billion around 1927. ( https://en.wikipedia.org/wiki/World_population) [wikipedia.org] So unless you assume everyone had many multiple of cooking fires, there is no f...ing way that is true.
When life isn't going right, go left.
(Score: 3, Funny) by maxwell demon on Wednesday October 12 2016, @06:15AM
In ancient times, the billion was much smaller. :-)
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by butthurt on Thursday October 20 2016, @10:54AM
Eighty percent of air pollution comes not from chimneys and auto exhaust pipes, but from plants and trees.
—Ronald Reagan