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Comment by robertlagrant | Hacker News Reader

The "last 800000 years" view is interesting.

Too bad they don't have a "last 6 million years" view -- CO2 was 1000ppm in the Cretaceous.

And the global averaged temperature was 20 degrees warmer. Also this increase has been faster by 100 fold compared to previous increases. This is about to get very chaotic and civilization crushing.

Not sure I can predict whether civilization(s) will be crushed, but I generally agree with you.

We can perhaps look at current trends and extrapolate. Currently at less then 1.5° C and we are seeing a lot of failed policies both regarding minimizing further warming, and dealing with the current damage.

We are seeing many people dying in various climate related disasters (by some estimate covid level numbers and growing).

We are seeing crop failures, a mass extinction event, we are seeing pests becoming more severe, both in the natural world (see the giant Sequoias in Yosamite) as well as in our crops. This will get worse. Note, we will probably have enough food, but just like now, it will not be evenly distributed. Expect famines in the future. Currently things are not so bad.

We are seeing a lot of people fleeing their homes, and we are not seeing anybody accepting them as refugees. As the climate warms further, one can expect either our refugee policy changes and we open our borders (unlikely) or we can expect wars to break out as migration crises become severe (likely).

As the global hunger increases, as global wealth distribution gets worse, and as the global poor are at serious risk of dying from climate disasters, famin, etc. As tension grows on our borders, and as our governments become increasingly hostile towards refugees, then I honestly don’t see how our democratic world can survive.

Of course our governments can make the right choice and open our borders, then it will be a different world, that still sucks from all our climate related disasters, but at least it might survive. The other option is a increasingly facistical world. Which in my book is definitely civilization crushing.

>global wealth distribution gets worse

It's got hugely better over the last 30 years (poor countries vs rich) and I see no signs of the trend reversing.

It will be bad news for any civilization who lives in low lying areas and will be completely underwater. Many island communities will be lost or displaced.

One thing the GP post didn't mention is that in that time period the entire US midwest was an inland ocean. Many counties that we have today simply won't exist.

20,000 years ago sea levels were 120m lower than today yet civilisation has thrived during that period and we've hardly noticed the rise. People move house every decade or so and the change in a decade has averaged 6 cm so it's possible to outrun it by moving.

20 000 years ago we didn’t have closed borders, nation states, global markets, etc. Heck, the crops we grow today and depend on were mostly still in their way less nutritious and harder to grow wild variants.

20 000 years ago we also had a massive number of big game animals which grazed in gigantic herds on vast prairies. These prairies don’t exist anymore, and neither do the herds.

On top of that, our historic sources don’t reach this far back, and our archeological records gets really blurry this far back, so what do you know. Perhaps there were multiple time periods where societies did indeed collapse, where a governing structure spanning an entire region was suddenly and violently disrupted and never returned, with cultures and languages lost with no descendants. Surely this happened multiple times between 30 and 20 thousand years ago.

Around 3000 years ago society in the Middle East, North Africa and Balkans certainly did collapse because of some volcanic eruptions and the subsequent migration crisis and the market failure of a single industry.

I googled the 3000 year ago thing and the Wikipedia for Late Bronze Age collapse says competing theories for the collapse have been proposed including volcanoes and also "disease, invasions by the Sea Peoples or migrations of the Dorians, economic disruptions due to increased ironworking, and changes in military technology and methods that brought the decline of chariot warfare."

So a lot of stuff going on really. I think similarly through our lives there will be all sorts of stuff going on such that the sea rising a foot or so will be not that noticable.

I think most historians agree that the Sea People invasions was a result of the migration crisis from Europe into the area. Whether the initial cause for this migration crisis was a volcano or some other disaster is kind of irrelevant to our discussion. What matter is something changed, causing people to need to migrate, causing wars and destruction, and an eventual collapse.

The climate crisis isn’t just the sea-level rise, I think civilization would survive Florida and Bangladesh going under (but it will suck). But our climate crisis is this sea-level rise at the same time as a bunch of wild fires, more powerful hurricanes, crop failures, droughts, ocean acidification, etc. All of this in tangent will result in mass migration, just like the Sea Peoples, just in the opposite direction. And unless our governments change their border policies (unlikely) there will be wars and destruction in our remaining cities.

I think the current thinking is that the sea people were a symptom more than a cause of the collapse. The few surviving records talk about crop failures and widespread unrest even before the sea people appeared. You had a number of feudal kingdoms teetering on the brink of collapse and the sea people provided a convenient excuse for the rulers so they didn't have to blame themselves.

Exactly. As I understand it the invasions came as a result of a migration crisis, this migration crisis was also a symptom of the collapse, i.e. something else (most likely devastating volcanic eruptions followed by nuclear winder, crop failures, etc.) which made life in Europe really hard, forcing the migration. I imagine these migrants weren’t super welcomed into the more rich Bronze age cultures, otherwise perhaps the migration might have been less violent, and collapse could have been avoided.

Just two more years.

Until what? What, specifically, do you predict will happen in the next two years, and why?

The Cretaceous is a lot farther back than 6 million years.

https://en.wikipedia.org/wiki/Cretaceous–Paleogene_boundary

If you can remember the Jurassic Park tagline (original movie), "an adventure 65 million years in the making", then you've got a good ballpark figure for this.

Don't think 6 million would be enough, the max temp and co2 levels of the Cretaceous was 66 million years ago, and the Cretaceous period was 145-60 million years ago.

That perioid may be a somewhat large peak in a co2 graph, making the current co2 increase look negligible. However ocean levels are also estimated to have been 50-100 meters higher than today at that period, along many other side effects.

When looking over a vast time like this with a high levels of variations and varying local maximums and minimums, linear graphs become misleading. If you were going to include the Cretaceous you would have to plot it logorithmically, but at that point the graph becomes uninteresting because every peak except the current one would be just slim lines.

Edit: I saw my dead sibling pointed to a graph which is some weird logarithmic-linear hybrid, i.e. it show three distinct timeperiods in three different scales. This is indeed a rather odd way of representing data, and I don’t think it is helpful.

I posted the longer view in my other comment, take a look here:

https://today.tamu.edu/2021/06/14/ancient-deepsea-shells-rev...

It is interesting - whats the validity of the historic data? Theres clearly some consistent patterns if that data is to be trusted.

Ice cores: https://www.methanelevels.org/#sources

Though scientific, it's still a guesstimate and not factual data.

> Changes in past atmospheric methane concentrations are determined by measuring the composition of air trapped in ice cores from Antarctica.

measurement, not "guesstimate"

Right, like every measurement humanity has ever made.

The historical data is based on an analysis of air bubbles trapped in Antarctic ice cores.

Yeah, esp. temperature and the global sea levels

Especially the 1px spike at the end

Seriously!! ;) The systematic monitoring of carbon dioxide levels in the Earth's atmosphere began in the 1950s. The Mauna Loa Observatory in Hawaii, established in 1958, has been continuously monitoring atmospheric carbon dioxide levels. So anything before that, I'd take with a grain of salt and maybe extra some cayenne pepper.

Methodology is described in the site - it's based on air composition frozen in antarctica.

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