Why 536 was 'the worst year to be alive' (2018)

Not at ice divides (like hydrological divides) where ice cores are taken (ice cores are almost always taken at divides because the ice flows apart, so the stratigraphy is not as disturbed). It's too cold to melt out there anytime soon. These are high-elevation locations, so there is either no melting (East Antartica ones ~3000 m) or extremely minimal melting, rarely, during the height of summer (Greenland and some other places in Antarctica). In Antarctica, surface melt is a rounding error everywhere, and response to climate change is almost entirely due to ice sheet-ocean interactions with a warming ocean and changing currents, and a thing called the marine ice-sheet instability.

At any rate, these locations will always be accumulation zones where more snow falls then melts (with the mass balance preserved by diverging flow so as to continuously thin the ice, to approximately compensate), with melt events occuring only rarely. The concern there is that meltwater could contaminate near-surface compacted snow (firn) layers, but even then it wouldn't be enough to do much. As such, stratigraphy will be reasonably preserved even if the ice sheet as a whole draws down significantly (including at divides).

Really extreme climate change (which is in the cards long-term) could eventually change this, especially if the ice sheets reduce enough in height such that a significant ice sheet-elevation feetback occurs. However, we'd have much bigger things to worry about at that point.

We have the most extensive data available for recent years, though. Ice core samples are also nothing new, they've been extensively studied for decades. Many of these cores are carefully removed and placed in ice cold storage warehouses: https://qz.com/1590747/an-antarctic-ice-core-may-show-1-5-mi...

> decades

The ice in Greenland is up to 3000 meters thick, and Antarctica is up to almost 5000 meters. Are you suggesting the net melt could average up to half a meter a year?

I had forgotten the exact number, i knew it was at least 7k. I didnt want to lie in my comment, but im almost sure you are right.

Im at work right now so cant look it up.

In this case the problem (other than weather) was 100% infrastructure: many of these roadways are built below grade, which means that when it rains, they flood. Floods are generally not part of the threat model for Bay Area infrastructure (though perhaps they should be), so when civil engineers trade off drainage vs. earthquake safety vs. land use vs. traffic, drainage is usually the first thing sacrificed. The mid-peninsula had 5 consecutive avenues underneath El Camino & the Caltrain tracks washed out; most of them have been recently rebuilt as grade-separated underpasses as part of the Caltrain electrification project, so that traffic would not need to cross the tracks. They probably would not have flooded as at-grade intersections.

Arguably this was the right choice, as everybody just stayed home during this storm, so real impacts were relatively light. By contrast, Bay Area traffic is a disaster every rush hour, so getting a few folks to take Caltrain instead of driving or avoiding just one collision on the tracks already puts you ahead of the cost of this weekend's storm.

Countries like the US and Canada, who are net food exporters, would basically be fine. China would face huge problems. Failed states would experience catastrophic famine.

The vast majority of that food is grown as animal feed. Only 27% is consumed directly by people. That's a huge buffer in an emergency.

Yup. There's a reason corn subsidies are what they are, for example, and it's not (just) politics.

Yeah vertical farming/hydroponics only gets you a very limited set of vegatables.

Beans beans the magical fruit

Modern LED grow lights require minimum 35 watts per square foot to grow things beyond just lettuce, which is around 1.5 million watts per acre. Americans currently consume a bit over 2.5 acres of farmland produce per year, however you could get that down to 1 acre without much problem by cutting out some of the less land efficient crops likes fruit trees, especially when talking indoor grow.

So I would expect bare minimum energy requirements to be near 1.5-2 million watts per person for 12-16 hours a day for indoor food sustainability.

This is of course not accounting for fertilizer which has large energy requirements or anything more than the most simple and basic of climate control.

And how soon would their building be turned into yet another polarizing issue, or their building farmed out to contracting companies who would make most of the money disappear?

A global response on the scale of Covid to build vertical farms would reduce the severity of the famine dramatically.

It would be expensive, but the alternative would be burning cities and food riots. I can hardly imagine the USA avoiding a civil war considering how divisive and hostile things already have gotten

You can get hydroponics going fairly quickly, the bottleneck would be the supplies and supply chain — materials to build the with

This is where history and archeology diverge.

We know how bad things were in Europe and East Asia because written records survive which describe the crop failures etc. We don't have records from that time period from Africa or South America. All we can do is assume that people there suffered as well, due to the global nature of the problem.

Sometimes people get left out of historical narratives because there just aren't any written records. You can make assumptions, or you can try to make stuff up, but an intellectually honest historian is also likely to just say "we can't know."

In contrast, archaeologists will try to make a case for how hierarchical a society was, or whether it was male-dominated, or what kind of religion it had, on the basis of a few tombs belonging to "high-status individuals" and a couple of pieces of pottery. It's always a bit of a stretch. A lot of what archaeologists believed about prehistory. especially migrations of people groups, has been overturned by genetic studies in the past decade. David Reich wrote a good book about it several years ago, which is probably itself outdated now due to the pace of discovery in that field.

This is irrational pearl clutching. If sulfur is added, it will be done gradually, with the results monitored. There would not be some sort of catastrophic cooling.

The real sticking point would be that some countries would not want the cooling. Russia, say.

We have natural experiments where sulfur aerosols were injected. The 1991 eruption of Mt. Pinatubo, for example. It injected 17 megatonnes of sulfur dioxide into the stratosphere, causing a global cooling of 0.4 C and a northern hemisphere cooling of 0.5-0.6 C. This also affected ozone, which suggests aerosols other than sulfuric acid droplets might be a better idea.