[arnaudsm]

With a more scientific approach, the IPCC[1] models show we could see mass migrations between 200M and 1.5B due to climate change before the end of the century. Not a total collapse, but the collapse of a dozen of countries due to unsustainable heat and drought.

[1] https://www.ipcc.ch/apps/njlite/srex/njlite_download.php%3Fi...

[johnmorrison]

Yes, this is much more accurate of our best predictions.

Bjørn Lomborg says[1] by the end of the century, climate change left unchecked will only lower the global GDP by a 2-4 percentage points of what it would have otherwise grown to, which is going to be 300-1000% higher than today. So basically, best case scenario 980% GDP growth, worst case 288% GDP growth.

This shows climate change is a problem, but it's too slow to cause a global catastrophe by 2100.

Even better news, I'm very confident it will not be left unchecked, in fact I think we can get to net-zero emissions by 2040 or so.

[1] https://www.youtube.com/watch?v=5QyXduteiWE

[littlestymaar]

This is an interesting answer. Somebody says there will be hundred millions of people fleeing their then uninhabitable countries (which will lead to millions of death, just look how many people drown in the Mediterranean see each year now, and how the European population is more xenophobic year after year). And you answer saying GDP will be fine!

[johnmorrison]

You're right, GDP growth does not outweigh deaths. However I don't think the primary issues caused by climate disruption will be human deaths, but instead the loss of assets in compromised areas. Humans will relocate, and lose a lot of wealth, but why would they die en mass?

> fleeing their then uninhabitable countries ... which will lead to millions of death

I'm not sure if this is true, actually. What is true is that millions of people every year die due to air pollution, but this isn't climate change, it's just our present pollution.

There's like ~50 million deaths per year if I recall correctly, and I'd be very surprised if more than 0.1% of that is caused by climate change. At least 5% of it is due to pollution, though, and I think probably more like 10%+

[littlestymaar]

> Humans will relocate, and lose a lot of wealth, but why would they die en mass?

What a wonderful world you live in. Do you genuinely believe it's that simple?

What do you think happens when 1 million people move from one country to another? They do not simply relocate, they are parked in camps (if you want current examples of that look at the Rohingya people, or Syrian refugees in Lebanon) until they can go back home, as you can guess the sanitary situation of these camp is more than precarious (cholera is a big threat for instance). With climate change, their will be no way back, and it's not going to be one million of people, but hundred millions.

What do you think would happen if a country, let say Italy for instance, had to park 10 million people in camps for years? Don't you think people in camps would eventually revolt violently to get out? What would Italians do then? Don't you think European countries would anticipate this outcome and just block refugees from entering, shooting the one trying to? Because it's already in the political agenda of most far-right parties here in Europe, and most of them are not that far from power (Salvini and Orban and just the first of a long series coming…). Due to the fight against illegal immigration, there already been thousands (around 17 000) of death in the Mediterranean see since 2014. And you can be sure it's not going to be better when all central Africa is uninhabitable …

And when people fleeing their countries are not accepted (as in “parked”) in neighboring countries, they just wander in the wild until everyone is dead. That happened for instance to people fleeing Rwanda to Congo.

Large scale population migration are incredibly difficult, and they almost always go wrong, and least a bit. Expecting 1 to 10% of the refugees dying isn't that pessimistic. From the figures discussed earlier, that mean between 2 and 150 million death. Which comes in the same ballpark as the biggest humanitarian disaster of the 20th century…

[johnmorrison]

I feel you're conflating two different types of migration, and the issue isn't nearly as big as your 150 million deaths figure.

Almost all countries have ample space that will still be habitable for their entire population in 2100, even if climate change is left unchecked.

Those that don't represent a small portion of the global population, certainly less than 500 million people. I grew up in Botswana, and I know that "all of central Africa is uninhabitable" is not a likely outcome anytime soon. Most of Africa is actually really good land to live in, and will continue to be fairly good through the century.

In any case, Italy does not need to "park 10 million people in camps". Italy is a tiny country in terms of land area, so why would they need to take so many? Russia and Canada alone could easily fit a few billion immigrants each if global warming is really severe in a few centuries.

The notion that the only solution to climate change is to move everybody into already crowded places doesn't seem to have a base. We can solve the migration problem with or without moving people into Europe.

Anyways, my core point here is (a) we won't need to deal with this migration anyways, because we will solve climate change way before it becomes necessary, and (b) even if we didn't lower our emissions, I'm confident we can solve the migration problem without millions of deaths.

[pfbtgom]

I'm less confident that a mass migration wouldn't result in millions of deaths. An example might be the partition of India and Pakistan in 1947. Only 14 million displaced, yet an estimated 200k-2 million deaths and another 2 million people missing[1]. In many ways, this planned displacement was a more favorable scenario than a chaotic climate refugee situation.

If we don't have a good answer to the relatively simple refugee migrations now (eg. Central America, Syria), then I have extreme pessimism that we will be able to manage a larger-scale, persistent event. Whereas with economic + political refugee situations we can always hope to resolve the root cause, with climate change it is simply the new normal.

[1] https://en.wikipedia.org/wiki/Partition_of_India

[pjc50]

> Russia and Canada alone could easily fit a few billion immigrants each if global warming is really severe in a few centuries.

Russia absolutely isn't going to do that, and who's going to pay to move them across the Atlantic to a country that they're not allowed to immigrate to?

I'm kind of leaning the other way: millions of avoidable deaths is the "normal war" situation, even if we magically solved climate change tomorrow.

[littlestymaar]

> Almost all countries have ample space that will still be habitable for their entire population in 2100, even if climate change is left unchecked

That's a really dubious one. There's multiple issues with global warming, drought and desertification being one of them (and it probably will not affect a whole country) but the second one is just the max temperature the human body can, withstand especially with high humidity. When this threshold is passed, you can have thousands of people dying at the same time in your country. When every summer, heatwaves take a few of your neighbours you start reconsidering how nice your country is.

Remember, we're going to have more than a 2°C increase in mean temperature by the end of the century, and maybe 4°C. 4°C is the difference between now and the last ice age when the whole Europe was covered by huge glaciers.

Also, many people live near shores, which will be damaged frequently as the see level rises… How would India, who have a borderline genocidal tendency (fantasised mostly at the moment buy still frightening) against Muslims nowadays, react to the massive arrival of Bengali people coming from Bangladesh after a typhoon destroyed their land?

> Italy is a tiny country in terms of land area, so why would they need to take so many?

Because that's where they arrive… I'm not speculating when I talk about Italy, this is happening right now (not 10 millions, but hundred of thousands).

> Anyways, my core point here is (a) we won't need to deal with this migration anyways, because we will solve climate change way before it becomes necessary, and (b) even if we didn't lower our emissions, I'm confident we can solve the migration problem without millions of deaths.

Regarding (a), you should probably read this https://en.m.wikipedia.org/wiki/Emissions_budget

Regarding (b), I admire your confidence, but it sounds delusional in regard of the whole human history.

[biolurker1]

cultural conflicts are the issue. There may be space in Italy for another 30 million inhabitants but soon you will have Muslims fighting Catholics (and getting slaughtered). That's a humanitarian disaster in my book

[mcv]

That's a big part of the problem. Policy makers have a tendency to care more about GDP than about people. As long as the numbers look good, people are mere statistics.

Rich countries are in a better position to mitigate the effects of global warming and climate change than poor countries. Rich people will be better able to insulate themselves from the effects that do occur in their country than poor people do.

Imagine New York is about to flood. Rich New Yorkers will probably already have a house somewhere else. The poor ones won't. And they can't afford to buy a new house if their current one becomes worthless. Their jobs are also more tied to the city than those of rich people. Moving Wallstreet will cost a lot of money, but that money is there.

[SamPatt]

Rich countries do indeed adapt better to climate change than poor, but the point about GDP is to show that in the future all countries will be rich countries (compared to the present).

If wealthy nations today can adapt to rising sea levels, and today's poor countries will eventually become just as wealthy, why will they be unable to adapt as well?

[ncmncm]

Rich countries are, visibly, adapting to increasing migration by adopting increasingly fascist governments. Is there any objective reason to expect this trend to reverse, as migration continues to increase?

Please explain your reasoning.

There is no reason to believe that countries that are becoming uninhabitable will become wealthy at the same time. The people who are best positioned to create wealth are exactly those who flee first.

[maze-le]

If the history of the last 40 years of "climate debate" teaches us anything, then that it will not only be left unchecked, but it will become worse. There is absolutely no reason to be optimistic about CO2 emissions on a global scale.

If zero emissions by 2040 is a realistic scenario, then we have to create the foundations of this development now. What we do instead is: lackluster regulations in Europe, active denialism and in the US, expansion of the oil- and gas industry in Russia and increased coal production in China.

[johnmorrison]

> There is absolutely no reason to be optimistic about CO2 emissions on a global scale. > we have to create the foundations of this development now

We are. The company I work at aims to eliminate ~60% of global emissions ourselves and provide the economic basis for the other 40%.

The only major section of global emissions that doesn't seem to have an obvious full solution is concrete production, which I'm sure we can offset with sequestration, and reduce with wood-based CLT construction.

Every other major component of emissions has a solution that is in active development right now, or already available and in the process of adoption. I think there's plenty of reason to be optimistic.

[jfk13]

> The company I work at aims to eliminate ~60% of global emissions ourselves

Well, nobody could accuse your company of having small ambitions!

When its website consists of little more than a few sweeping "We will [...]" statements and a lot of "This page is missing", though, you'll perhaps understand if some people are a little sceptical.

[johnmorrison]

Yeah we're updating that at the moment, the site isn't a big priority so we don't have anybody full time on it.

Will be fixed in a week or so.

[BregorMarRian]

By the way, Bjørn Lomborg is an unreliable and often misleading source. Why? See for yourself multiple examples of quality analysis with actual scientific sources. Highly recommended: [1] https://youtu.be/9FQX1u-aqrA [2] https://youtu.be/hwMPFDqyfrA

And that's analysis of Bjørn Lomborg's work by those who actively support pragmatic, cost-effective, and often 'conservative' solutions to environmental problems and climate change. Examples: [3] https://youtu.be/D99qI42KGB0 [4] https://youtu.be/6fV6eeckxTs

[mr_overalls]

Bjørn Lomborg's education is in political science and statistics. His analyses, while occasionally thought-provoking, are opposed by the vast majority of actual working climate scientists. He has gotten a lot of attention by simply being a climate contrarian.

[johnmorrison]

The same implication could be made about climate scientists, who are not trained in geopolitics or economics. I don't think it's fair to box people in based on their education, and also, there isn't any degree which really qualifies you fully to discuss the geopolitical and economic impacts of climate science.

[mr_overalls]

> The same implication could be made about climate scientists, who are not trained in geopolitics or economics.

Yes, that's exactly what I'm saying. I would take a climate scientist's opinion of macroeconomic trends with a grain of salt, to say the least.

PhD's are a deep dive into a very narrow field of study. They are most definitely not a "universal expert" certification.

[kostarelo]

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[arnaudsm]

Sorry for the broken link, Google URLs on mobile are a mess. Here's the link : https://www.ipcc.ch/apps/njlite/srex/njlite_download.php?id=...

[xenocratus]

URL doesn't work