Ominous milestone for the planet': Arctic Ocean's 1st ice-free day could be just 3 years away, alarming study finds

[Admin]

The Arctic's ice cover could dip below a crucial threshold as soon as 2027, and will do so inevitably in the next 20 years if greenhouse gas emissions continue, scientists warn.

Ominous milestone for the planet': Arctic Ocean's 1st ice-free day could be just 3 years away, alarming study finds : Read more

 

[orsobubu]

co2 doesnt affect the climate, since it already reached the saturation point millennia in the past

 

[COLGeek]

co2 doesnt affect the climate, since it already reached the saturation point millennia in the past

Source, please.

 

[D M]

As with COLGeek, assertions are fine during brainstorming or for reiterating consensuses but have no place in trying to change the consensus. People have put thousands of lifetimes into studying CO2 so any questioning of their conclusions needs actually to provide a decently demonstrative reference.

 

[Unclear Engineer]

So what does the climate model say will be the consequences of the Arctic Ocean becoming ice-free in the summers? And, is that being modeled in conjunction with the predictions that the Atlantic Meridional Overturning Current will collapse and cool the land areas in the North Atlantic region?

Could this "global warming" restart glaciation in the northern hemisphere, with colder temperatures and an increased source of moisture to create more snow on land areas?

Something like that has probably happened dozens of times over the past few million years, but we don't seem to be able to model how it happened before.

So, the question in my mind is whether the increased CO2 emissions from human use of fossil fuels has stopped that cycle or perhaps speeded it up, compared to the unperturbed processes.

 

[D M]

I suspect the jury is out on that one, it's been noised around for a possibility for a while. Either way not too good for stability. A little bit of change can obviously be beneficial, too much change too suddenly can be a bit catastrophic. Civilisation relies on stable farming, which relies on stable climate & weather as for crops at least each year you have to know what to grow and when.

 

[Unclear Engineer]

I agree about the stability needed for a complex global society.

But, I also note that our society has become global during an unusually stable period compared to the last few million years. This interglacial period has been longer than the norm, and we probably would not have reached the levels we have achieved so far if we had experienced a more normal interglacial period.

So, the question seems to be whether we can learn to adapt our unwieldy support systems to more rapid changes. I don't think we are likely to be able to really control climate well enough to keep things stable for tens of thousands of years. The geological evidence of rapid changes in the past few million years already show a range of large, rapid changes in temperatures, sea levels, rainfall patterns, etc.

 

[Ravens]

The warning that atmospheric CO2 levels should not exceed 350 ppm was passed in 1988 and is now above 422 ppm. (IMO, atmospheric CO2 levels should not exceed 300 ppm.)

 

[Unclear Engineer]

Ravens, the atmospheric CO2 levels have ranged well above 300 ppm in the past, without any inputs from humans. Here is a graph of the CO2 levels since the dinosaurs died:
https://media.news.climate.columbia.edu/wp-content/uploads/2023/11/CO2-curve2.png
The line is the CO2 concentration, which can be read from the scale on the right. The colors are indications of climate average temperature, with red for hot and blue for cold. You can see the correlation. But, note that the CO2 concentration has generally been far above 300 ppm for most of the last 66 million years. And note that the planet has been colder over the last 3 million years than any other time since the dinosaurs died.

So, humans are unlikely to be able to maintain what is a relatively uncommon climate for our planet.