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Rain at the Summit of Greenland

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132 pointsKaibeezy45 comments

"This is coal, don't be afraid, it can't hurt you"

-- Prime Minister Scott Morrison, 2017

https://www.theguardian.com/global/video/2017/feb/09/scott-m...

Reminds me of Thanos... We are on a path to drastically downsize the human population. We could stop it but that would mean millions of wealthy people have to make less but they are going to need money so they can buy the only land that remains livable.

OnlyFans bans porn: over 1000 comments.

Tesla announces humanoid robot: 190 comments.

Rain at the summit of Greenland: 1 comment, after 7 hours.

Please don't break the site guidelines like this.

"Eschew flamebait. Avoid unrelated controversies and generic tangents."

https://news.ycombinator.com/newsguidelines.html

Fresh water pouring into the North Atlantic is what will shut down the Gulf Stream, plunging northern and western Europe into a far colder climate more typical for their latitude. Yeah, you’d think this would be bigger news.

See also Warning Signals for Collapse of the Atlantic Meridional Overturning Circulation, Nature, 2 weeks ago (good discussion that got shut down as a duplicate, although it’s the primary source paper and all the rest were secondary, but whatever, bots or something): https://news.ycombinator.com/item?id=28085342

We don't control the AMOC or any other oceanic cycle, including the AMO, PDO, ENSO, etc.

If the AMOC reduces circulation, then the planet will cool as a whole, and we'll probably find ourselves retreading into a Little Ice Age, as experienced from the 1400s to mid 1800s.

At any rate that would be counter to the projections of runaway warming.

Why does reduced circulation cool the planet as a whole? I would expect the heat to stay where it’s hot in the tropics and the cool to stay where it’s cold in the poles, with hurricanes and tornadoes making up the vortexful barrier between them, but iana fluid dynamicyst

IIRC, when the Arctic stays cold, there’s more sea ice, which reflects more sunlight than open water, reducing total/overall temperatures.

ETA:

The sea is dark; the ice is white. That makes a big difference when it comes to reflecting sunlight. The dark sea absorbs heat while the ice reflects a much larger proportion of the sun’s energy (the “Albedo-effect”). So a smaller sea ice extent means more open, dark water, which results in more absorption of the sun’s energy in the seawater, and thus more warming of the seawater.

The warmer seawater raises the temperature of the air above, which means that ice formation will take place later in the year. And next year, when melting sets in, there is less ice and melting may happen faster, which means that the sea is open to absorb even more energy from the sun. And so on.

Scientists call it a positive feedback that enhances the changes even further. And this specific feedback has been documented in the Arctic. To what degree this will have effects outside the Arctic is still an open question.

The diminishing sea ice also has the potential to change global ocean circulation. In the Arctic Ocean, especially east of Greenland, a process takes place that is considered to be crucial for the circulation of the oceans. As the waters flowing north to this area cool, sea ice forms; leaving the water below the ice much saltier and denser. This heavier water sinks to the bottom and flows south along the deep plains of the Atlantic Ocean.

The force of this, in combination with similar processes in Antarctica, is so tremendous that these mechanisms actually fuel global ocean circulation. The cold water follows the bottom of the Atlantic, resurfaces, for instance, in the Indian Ocean and returns as a warm ocean surface current in the Atlantic Ocean, commonly known as “The Gulf Stream”. The system is often referred to as “The Great Conveyor Belt”.

To what extent “The Great Conveyor Belt” will be affected by the diminishing Arctic sea ice is still an open question.

http://polarportal.dk/en/sea-ice-and-icebergs/understanding-...

The issue is the Arctic is not likely to re-freeze even with Gulf Stream gone.

This is a little bit like bi-stable switch. Once it switches one way it wants to be in that position until there is enough force to push it the other way.

I see what you’re saying. The Gulf Stream affects ocean water distribution worldwide, but doesn’t necessarily have much affect on the Arctic Ocean itself.

Of course it makes it a little warmer, but the point is, the most important factor that makes Arctic Ocean... well... arctic... is whether it reflects sunlight or not.

Water is dark and accepts a lot of sun's energy, getting warmer.

With ice present it reflects a lot of that energy back to space.

The amount of energy difference we are talking about is astounding. The Gulf Stream, as large as it is, pales in comparison to the amount of sunlight reflected by patch of snow the size of entire Arctic Ocean.

Now, I don't want to say Gulf Stream is insignificant. It will definitely have huge effect, especially on Europe where I live.

The most important effect, per my understanding, is less rainfall. Because that warm water vaporizes and those vapors tend to turn to rain/snow over Europe.

Shift in wind patterns I don't understand so can't elaborate.

If the water goes below freezing temperatures, it will tend to freeze and turn white. If the hot tropics are currently pulling warm water up towards the Arctic via the AMOC, the average water temperature of the Arctic is increased. If that pattern were to decrease, you would get colder Arctic water that tends to freeze more easily.

A lot of ocean water is already covered by something else with albedo: clouds. Particularly in the poles, clouds tend to form very easily.

Reduced AMOC circulation is associated with dramatic effects in the past for Earth's climate.

"The Little Ice Age was one of the coldest periods of the last ~10,000 years in the Northern-Hemisphere. Although there is increasing evidence that this cooling was associated with a weakening of the Atlantic Meridional Overturning Circulation (AMOC), the sequence of events that led to a significant reduction in deep convection has yet to be explained." https://instaar.colorado.edu/meetings/AW2021//abstract_detai...

> A lot of ocean water is already covered by something else with albedo: clouds. Particularly in the poles, clouds tend to form very easily.

You are wrong.

Antarctica is the driest place on Earth. https://www.google.com/search?q=driest+continent+on+earth

"Antarctica is the driest continent; it is almost entirely desert. Very little snow or rain falls on the continent (...)"

Dry == not much cloud cover.

And if there are ice crystals in atmosphere it mostly shows as haze, it is not effective at reflecting large portion of the sunlight.

Clouds form from moisture from evaporating water. This usually requires warm water to be significant. In northern hemisphere this warm water is supplied by Gulf Stream.

Also, as a side note, clouds are not nearly as effective at reflecting energy back to space as snow is.

First, ice is there all the time, every day. Clouds are rarely continuous for long periods.

Second, clouds are scattering light. Of which some goes back to space. Snow is reflecting it.

I know on picture they both look white because humans are poor at discerning levels of whiteness.

https://en.wikipedia.org/wiki/Cloud_albedo "Cloud albedo on a planet varies from less than 10% to more than 90% and depends on drop sizes, liquid water or ice content, thickness of the cloud, solar zenith angle, etc

Clean snow has albedo of 90%, which is the best clouds can get in optimal conditions, but rarely actually get there. And difference between 90% and 80% of albedo is TWICE the amount of energy absorbed.

Without it there is not going to be a lot of clouds and rain in northern Canada or Europe. And arctic is already quite dry.

Of course, my comment was on cloud cover above water, near the poles, including the water surrounding Antarctica, which has frequent snowfall including as we speak. Take a look at current satellite imagery of the area surrounding Antarctica: https://www.windy.com/-Satellite-satellite?satellite,-63.744...

Cloud cover is more common over ocean water than on land.

Also, Antarctica's cloud cover is larger in the winter than in the summer: "The seasonal cycle of cloud cover is found to range from 45%–50% during the short summer to a relatively constant 55%–65% during the winter. "

https://journals.ametsoc.org/configurable/content/journals$0...

You can find similar studies on the cloud cover above exposed water in the Arctic.

It doesn't matter how variable clouds are, what matters is an average over a long period of time. Clouds have a far more dramatic effect on global temperatures, because they have the ability to reflect absorption of solar energy in the hottest parts of the planet (the tropics), where ice cannot exist. They can and do form over most of the ocean water which covers 2/3 of the planet's surface. Average cloud cover over ocean water is 90%!

Some clouds scatter light. Some are extremely effective at reflecting light into space. Depends on zenith angle of the light (based on latitude), the altitude of the cloud, water content and shape and thickness overall.

https://www.researchgate.net/publication/334183298_High_clou...

The northern hemisphere has an outsized effect on global temperatures, because there's more land area in the northern hemisphere. As mentioned in other comments, albedo (reflectivity) from sea ice (as well as clouds) reduces solar input into the Earth climate system. But also, more importantly, land ice and snow extent also can have an effect on Earth's average albedo.

If less warm water from the tropics is being pulled up towards the Arctic via the AMOC, not only will sea ice form more easily, but temperatures will tend to stay colder in northern latitudes in North America and Europe in particular, which is conducive for longer winters, great chance of standing snow cover, etc.

"Crippled Atlantic currents triggered ice age climate change" https://www.sciencemag.org/news/2016/06/crippled-atlantic-cu...

"What Caused the Younger Dryas Cold Event?" https://pubs.geoscienceworld.org/gsa/geology/article/38/4/38...

There must be a fairly large number of people who flag submissions related to climate change. They disappear quickly from the front page.

but why?

The threads such submissions generate tend to be full of flame wars, so there is a fraction of the userbase which doesn't believe climate change is a big deal, and I suppose there is a fraction of the userbase that doesn't like topics that generate flame wars.

I suspect many flags come from client change deniers; both paid shills and folks influenced by said shills.

From the HN guidelines [1]:

" Please don't post insinuations about astroturfing, shilling, brigading, foreign agents and the like. It degrades discussion and is usually mistaken. If you're worried about abuse, email hn@ycombinator.com and we'll look at the data."

Also, the article is currently on the front page, so the discussion about it being buried by flags is moot.

[1] https://news.ycombinator.com/newsguidelines.html

Where can I sign up to be a paid shill? Moreover, is HN considered a large enough community for people to _pay_ to shill on topics unrelated to tech/startups?

I don’t think you get paid to shill. The real money is in convincing others to volunteer to shill on your behalf.

I have to say I didn’t notice anyone saying anything positive or dismissing about the climate change on HN lately, it seems we generally agree that the problem is very real. Although it seems that when it comes to solutions - lots of discussions and disagreement there.

Always the right question, Mathesar.

The first two are fun and interesting. This one is just depressing. There isn't much to add, especially when such news become regular.

No one wants to talk and think about the coming collapse and if things get worse, extinction event...

Even in the worst case scenario it's not an extinction event. Probably at least 50% will survive.

50% of species would be considered an extinction event, and that is absolutely on the table.

We're already in the 6th largest mass extinction event in the history of life on this planet.

I would strongly recommend reading Peter Ward's "Under a Green Sky" (or his academic papers if that's more your style). He makes a very compelling argument about the relationship between rising CO2 and many of the previous major (and minor) extinction events.

To be clear, I'm not saying "extinction is certain!" but in "the worst case scenario" mass extinction is absolutely a real possibility. If we reach the neighborhood of 5+C (which is in the realm of possibility, especially when talking about 'worst case') we're looking at a planet that is very hostile to human and most other current life.

A few books I would recommend (all in the popular non-fiction category but backed up with plenty of academic sources):

- Peter Ward "Under a Green Sky"

- Elizabeth Kolbert "The Sixth Extinction"

- Mark Lynas "Our Final Warning: Six Degrees of Climate Emergency" (update of his earlier "Six Degrees")

Ward is an academic, and Kolbert and Lynas are science journalists, but both have plentiful, credible citations.

Again, there are so many big unknowns that very little can be said for sure, but saying that a mass extinction (and more specifically human extinction) event is not possible is simply wrong given our current understanding of the situation.

4 billion? I doubt that.. Wars will start over water, food, land..

In a world that's seemingly falling apart, OnlyFans keeps people sedated and somewhat happy.

How I interpreted these before seeing this comment and its children:

> OnlyFans bans porn: over 1000 comments.

> Tesla announces humanoid robot: 190 comments.

> Rain: 1 comment, after 7 hours.

Those who are old enough will certainly remember the ozone hole, then the global warming and now finally "climate change". All the previous ones were dismissed/forgotten by the press but I like "climate change" because it can never be proven wrong.

The climate has always changed so you really can't miss this time. ^_^

Nevertheless, historical evidence documents how the climate has _always_ changed across the thousands of years. More snow or less snow across 20 thousand years is normal.

This university page does a proper collection of the related sources: https://faculty.ucr.edu/~legneref/bronze/climate.htm

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