Update October 21, 2018: The post below is all wrong. Here is the retraction.

Global Warming will have a gigantic impact on earth — but how will it affect me, and my children? Should we move further north? Learn how to live off the land? Expect war? Not do anything different? What? It’s been bothering me for a long time that I couldn’t answer any of these questions with any degree of confidence. (Is there any good literature on the subject? I don’t know of any, although that means nothing; it may very well exist. Pointers, anyone?)

Similarly, if I don’t understand how it affects other people in other places, I cannot understand global implications, such as how likely the sometimes-predicted wars are going to be, and between whom — something that is definitely something I’d like to understand.

So on a long solo drive this past Friday, I had plenty of time to argue with myself and reason things out. Here is what I came up with. I am aware that it’s very basic qualitative reasoning with no attempt at estimating the size of various impacts; it’s terribly incomplete, and probably wrong in places, but much better than the nothing I had before. So I’m much happier than before, and post this here in case it helps somebody else’s line of reasoning. I appreciate your comments with improvements.

My assumptions:

• For this post, I’m not interested in the causes of global warming, how to stop it or mitigate it, who caused it or anything like that. I only assume that it is happening.
• To keep things simple, I assume that two major things are changing:
  1. global average temperatures are rising. In some places, the temperatures will rise more and in some less (or perhaps even fall), but most places will get warmer.
  2. there will be more, and more extreme weather events, such as unprecedented heat waves, and in particularly stronger storms such as hurricanes.

That’s all that I’m assuming. So how will that affect me?

To determine that, I follow cause and effect along a chain: If X happens, then Y is more likely to happen. If Y happens, then Z is more likely to happen. Etc. Until I come to the effects that impact me.

And in the first step, I already need to claim complete ignorance for a big part of first-order effects: so I’m dividing the first-order effects of my two assumed changes above into two categories, the first of which I can reason about, and the second of which I cannot, because I do not have enough knowledge about it:

1. Direct effects on humans or humanity. For example: More hurricanes means more destroyed residences, which directly impacts people.
2. Effects on ecosystems or other systems that do not directly include humans, where humans are affected only in a 2nd-order or later effect. Example: Higher ocean temperatures mean dying coral, which in itself has no impact on humans (other than divers). It may very well have big second-order effects on humans, such as the collapse of food chains that cause fisheries and thus human food sources from the ocean to disappear.

So for my purposes here, I have to ignore everything in the second category. Fortunately, the first category is good enough to come up with some interesting insights.

Having said that I’m only focusing on the direct effects on humans and humanity, it appears useful to look at different geographies / countries / economies separately, because impacts are certainly going to be different. Let me start with California, the place I happen to live:

• If temperatures are rising in California, it stands to reason that demand for water increases, while, on average, the supply for water shrinks. Recent droughts brought that point home already. What if the trend continues and intensifies? Well, it appears that water will effectively become more expensive (either through higher prices for water consumers, or through additional regulation about how water can and cannot be used, or additional needed investments in water recovery and recycling etc), which will hit the marginal consumers the most. Who, in California, are mostly farmers in the Central Valley that consume a large percentage of all water in the state, often at very low prices, in order to produce lots of food. So they will be squeezed out of the water market, and as a result, the volume and quality of California produce will fall. (I think this effect is already in full swing. I’m noticing lots of property for sale in the Central Valley.)
• If farmers in the Central Valley can produce less, some of them will need to pack up and move somewhere else. And because the Central Valley is largely driven by agriculture, lots of other businesses that cater to them will fold as well, from farming equipment retailers to banks loaning to farmers and dentists fixing their teeth.
• While the amount of produce grown in California will fall, it is not clear that this causes a reduction in available food: as some places will produce less, others further north might produce more and California will have to export less and import more. So I’m not expecting a reduction of food available to consumers.
• As agriculture is a small fraction of the Californian economy (less than 2%), this will have only a small impact on the overall wealth of the state.
• There are also going to be more, and larger wildfires. This trend appears to be well under way, too. What’s the impact here? As many of the forests in California do not appear to be commercially used much, there seems little economic impact. However, lots of people live in those many, beautiful forested places in the state — I’m always tempted myself — and so more people are at risk that their property burns down, and more frequently as well. The consequences: 1) essentially higher taxes on properties in nice places (more investments are needed in making the houses survive fires with metal roofs, large water reservoirs, fire breaks etc), even more frequent complete rebuilds, and 2) fewer people wanting to live in places that until recently were more appealing.
• I’m not expecting meaningful impact from severe weather like hurricanes etc as traditionally there haven’t really been any here.
• With higher temperatures come rising water levels. This might make places like Alameda island, on the other side of the Bay across from San Francisco, uninhabitable. There may be a whole bunch of those in Southern California.
• Will it ever get too hot to live in California? Given that people live in neighboring Arizona, it appears there’s much that money and air conditioning can do. So probably not.

If we summarize the impact on California, it would be:

• some things are getting more expensive;
• some people will need to move.

Neither of which are particularly fatal for anybody. Obviously, the poor are hurt the most, as they always are, and if you live in certain areas, you might have to write off your real estate investment. But by and large, California is a rich place, with lots and varied land, and a very diversified economy, so I think we’ll do okay.

Personally, I’m not a farmer, I don’t live in an area that is likely to ever be affected by wild fires, my house is well out of the range of even the most pessimistic water level rise predictions, and it appears that as long as I can afford the things that get more expensive, the direct impact of global warming on me should be minimal.

So far so good. What about the rest of the United States?

Some places will have similar dynamics as in California. But others are markedly different, such as the entire eastern seaboard and the gulf coast:

• If there are higher ocean levels, and more hurricane activity (and frequency and intensity), lots of people and places along the coasts are directly impacted. Miami Beach, for example, might will disappear below the waves even without a hurricane. And hurricanes, even before Global Warming, strike as far up as New York.

Interestingly, the high-level consequences are the same as in California:

• some things are getting more expensive;
• some people will need to move. Comparatively speaking, it appears that would be more people than in California: essentially everybody directly along the (usually rather flat) coast.

But while terribly inconvenient and very expensive, again, I think we will do okay: there are plenty of places within the US that one could move to and find gainful employment, so nothing particularly fatal is going to happen. I think a similar argument applies to most of Europe.

Not so in other places in the world. Let’s take Syria.

Syria has some parallels with California: water is scarce, and agriculture is losing. But unlike California, 20% of Syria’s economy is agriculture, and it is a poor country that has few sources of external revenue. If you are a farmer in Syria, and global warming makes it increasingly impossible for you to bring in enough crops to feed your family, what do you do? Or what do you tell your children to do?

In California, you’d say: learn how to program, and move to Silicon Valley, I will see you on the weekends when you drive back home in your shiny new Prius. In Syria, I can think of only one thing I’d say to my children, and that would be: there is no future for you in this country, you need to move somewhere else that 1) isn’t as hot, and 2) has a diversified economy with high GDP per person.

Anybody wondering why all those Syrian refugees are pressing into Europe? It’s quite clear if you look at the map that that’s the place to try and get to: it meets the requirements, is not too far, has a (so far) reasonably accommodating refugee policy, and is certainly much better than other places you might be able to get to: for example, all the countries around Syria, Israel excluded, largely face the same problem. And you can’t get into Israel.

The other option, of course, in Syria is to fight with your fellow citizens over increasingly scarce resources, aka Civil War, which is of course what we’re seeing as well.

Let’s move to Asia: much of Bangladesh, home to 160 million mostly poor people, is prone to severe weather and very low-lying along the Indian Ocean. As as farmer, you may get enough rain; but more likely you get so much of it, combined with taifuns, that your economic livelihood gets threatened even more than it has been so far. What will you do? I cannot think of any other course of action than attempting to get out to a better place. A similar argument might apply to many people in many other countries around the Indian and Pacific Oceans.

There is another effect. some places in the world are simply becoming too hot to live in. The so-called wet-bulb temperature is a good measure for that, as it combines temperature and humidity. Personally I made an acquaintance with this problem when visiting the ruins in the Yucatan: although we went early in the morning, I don’t know just how long I would have made it in the hot, humid jungle. I’m sure there are people who can tolerate much higher levels of heat and humidity than me, but there is a limit. Here’s a great map that projects where some of the hot spots are going to be. Note, for example, how much of South America this includes.

See the common pattern? It’s this:

• If you live in a rich country with a diversified economy, global warming will mostly affect you in the form of higher costs for some things. Some people will have to move, and those with the wrong investments may lose them. But as a whole, the people in the rich country will be fine.
• If you live in a poor country somewhere where it’s hot, or along a shore, you are in trouble. Your country cannot afford the tons of investment and education it would take to mitigate the global warming impacts or build up a diversified economy that would compensate for lost income. Your choice, by and large, is worse poverty and resulting more deaths or to pack up and leave.
• And this is where the collision occurs: more and more poor people in badly affected countries will be knocking at the doors of the rich people in moderately affected countries, who, on current political trends will spend their money on keeping them out, instead of helping them.

So if I were the emperor of the world? Invest, large-scale, into reducing the amount of global warming that is going to occur through all the things the Paris Agreement has in it, just more so. Invest massively into the economies of poor countries that will be not-too-badly affected, to prevent the need of mass migration from there. And establish a global resettlement scheme by which badly affected people can resettle in less affected places, at scale.

Given I’m not, this leaves me with two conclusions: it helps to be (comparatively) rich, and no, none of us in California or anywhere in the rich western world deserved this privilege.

Time to de-privilege ourselves in the western world, and systematically en-privilege everybody else? This would be a good idea, and not just to mitigate the effects of Global Warming.