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wren

@wren@feddit.uk

ello! (they/them)

This profile is from a federated server and may be incomplete. For a complete list of posts, browse on the original instance.

wren ,
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I am aware you already have a good profile picture now! but you may as well have these squid offerings since i made em :)

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wren ,
@wren@feddit.uk avatar

This article isn't perfectly scientifically accurate but it's better than most! For those interested, here's a better (detailed) explanation of the science:

Cloud seeding works best in supercooled liquid clouds, which start with barely any ice in. For ice to form in clouds, you need INP (ice nucleating particles), aerosols such as sea salt, or dust, for the ice to grow onto. INP can be pretty rare, depending on where you are in the world.

By adding silver iodide (an efficient INP) ice crystals can form. This means the cloud has both ice and liquid water in (a "mixed phase" cloud).

For multiple reasons, ice grows better and faster than liquid cloud droplets (the "Wegener Bergeron Findeisen effect" for one). Because there's only so much water in the cloud, these ice crystals then grow at the expense of water droplets in the air, allowing for big snowflakes to grow, but droplets evaporate.

This turns it from a cloud with many tiny droplets, into one with big heavy snowflakes, which fall out of the cloud. Before the snowflakes reach the ground, they melt, turning into rain.

TLDR; cloud seeding takes the water already in the cloud, and makes it precipitate slightly more efficiently, but only if you improve the balance of aerosols in the air just right

wren ,
@wren@feddit.uk avatar

good question!! I actually might have been mistaken by saying sea salt was an INP (whoops).

Sea salt is a great condensation nuclei (CCN). CCN allow cloud droplets to form instead of ice crystals.

For cloud seeding to work well, it's better to seed with INP instead of CCN because if you encourage lots of droplets to form, all you get is a bunch of really tiny droplets, making a really bright white cloud (no rain!). (Side note: that's why rain clouds look dark: they're made of fewer really big droplets.)

Adding sea salt to clouds is a thing though! It's been proposed as Marine Cloud Brightening - adding lots of sea salt to the air over the ocean, making the earth more reflective to combat further global warming.

As far as I know, most inorganic salts are good INP or CCN, but have varying efficiencies. Sea salt dissolves in liquid water whereas silver iodide doesn't, and silver iodide has the right sort of hexagonal crystal lattice for ice to start sticking to. So silver iodide is a great INP whereas sea salt is a great CCN.

Even longer (and reasonably silly) explanation here:
https://www.acsh.org/news/2022/09/01/why-are-clouds-seeded-silver-does-it-work-16538

Snow and ice are a way of life here. See how a lost winter upended that. Wisconsin’s Northwoods are normally a playground of snow and ice right now. But life here has become unrecognizable. ( wapo.st )

It is the second straight winter of extreme Wisconsin weather, but at the other end of the spectrum. A year ago, parts of the Northwoods were buried under more than 100 inches of snow, over twice their average snowfall....

wren ,
@wren@feddit.uk avatar

So much beautiful snow photography (stock footage etc) comes from Wisconsin. It's well known for snow and snow research. Sad to see the landscape changing over there

wren ,
@wren@feddit.uk avatar

Surprised to see none of the comments mentioning the 4B movement

wren ,
@wren@feddit.uk avatar

it's a feminist movement, in backlash to misogyny and pro-natalism in South Korea (it's becoming more widespread, though).
The 4Bs are the "four no's":

  • no dating men
  • no sex with men
  • no marriage with men
  • no childbearing

It gets a lot of pushback and is called selfish etc. but women are very angry & upset that the government only sees them for their reproductive use, and it's reasonable to not want to date someone who doesn't view you as human.

‘Does rewilding sort climate change? Yes!’: UK expert says nature can save planet and not harm farming ( www.theguardian.com )

The Knepp estate in West Sussex is home to the first white stork born in the wild in Britain for over 600 years. It’s a place where endangered bats, turtle doves and nightingales are thriving, where “officially extinct” large tortoiseshell butterflies are breeding and where tens of thousands of people visit each year to...

wren ,
@wren@feddit.uk avatar

I've never heard anyone complain about dry land farming before! I've had a brief Google and all the sources I can find are pro dryland farming because it's more sustainable/resilient/uses less.
is there analysis somewhere that says otherwise?

wren , (edited )
@wren@feddit.uk avatar

Interesting, thanks! Whilst supposedly simple, I think it might be pretty counterintuitive to some people.
I've often seen that dryland farming is lower carbon footprint per kg of food produced (i.e. per bag of flour), but carbon footprint isn't all that matters to the environment (and I'm not entirely sure I trusted those sources anyway).

EDIT: Thought more about it and definitely agree even in addition to the carbon footprint thing. When doing carbon footprint calculations, people don't take into account the possibility that the land could be used for something much better (i.e. rewilding).

wren ,
@wren@feddit.uk avatar

Where were you when I was doing a research project on wheat!? I'm not based in agriculture science at all, but supposedly, wheat in South Africa has the lowest carbon footprint in the world, but we still didn't recommend that the client used wheat from S. Africa because it didn't seem sustainable and the yields were low. I had no idea it was that bad, though.

wren ,
@wren@feddit.uk avatar

I've been keeping an eye on the ensemble since early last week - at one point it was forecast that Cornwall was going to get 6 inches of snow! Snow is notoriously tricky to forecast unfortunately

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