[tsimionescu]

[0] shows estimates of sea level rise from ~0.5m up to 2.5m by 2100. This alone will induce catastrophic flooding in some of the world's most populous cities and regions.

[1] covers some estimates of how prevalent wet bulb temperatures of >35C (the upper limit for a healthy adult to survive outside in the shade) will become. Any heatwave in this area will kill many vulnerable people and will stop almost any outdoor economic activity.

These are just 2 easily quantifiable numbers that will directly make life much harder in the next century (and the problems won't stop in the century after that). The second order effects can also be imagined.

[0] https://www.climate.gov/news-features/understanding-climate/... [1] https://advances.sciencemag.org/content/6/19/eaaw1838

[lopmotr]

Thank you, but that doesn't quantify catastrophe. I mean numbers of dead, cost in dollars, etc. Maybe we can cope with those 35 degree events by staying in air conditioned buildings like people already do in SE Asia. Maybe cities can move. The world's biggest(?) (Shenzhen) didn't really exist at all 80 years ago, or even 40 years ago.

[tsimionescu]

Here [0] is a study that found that, with the current trend, climate-related deaths per year in 2100 will be near the total infectious-disease related deaths per year today.

Also, Shenzen is only ~20th biggest city in the world [1], and its age is the exception, not the rule. The majority of the world's most populated cities are older than the countries they are located in, many of them being continuously inhabited since prehistoric times. Also, while creating a new city and populating it is possible with somewhat limited human harm (though rural->urban migration has its human impact, to be sure), deopopulating and moving a city of tens of millions (say, New York City, which sits at 10m elevation) is an entirely different scale of human displacement.

[0] https://www.nber.org/system/files/working_papers/w27599/w275...

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

[lopmotr]

I assume you're using that 85 deaths / 100000 annually which is for the worst case scenario of RCP8.5. With the more reasonable RCP4.5, it's only 14/100000, less than road deaths today. Road death rates have already plummeted by a factor of several over the past few decades. So we've already suffered far worse than the effects of 2100 climate change just from the direct danger of cars.

Since we'll probably continue to have improvements in safety, diseases, etc. between now and 2100, the world should be a safer place for humans by then. So it doesn't make sense for people to worry their kids will suffer a bad world due to climate change. They'll most likely enjoy a better world than us despite climate change.

Did you mention preshistoric occupation to suggest that continuous occupation is necessary for a city? That surely helps but if an area has to be vacated, people will obviously go somewhere else, probably another place that was already occupied. Cities renew themselves anyway within the climate change kind of time frame. Buildings usually aren't designed to last more than 50 or 100 years. People obviously don't last longer than that either. So cities of 2100 will likely contain mostly new buildings and people that don't exist today, while today's ones will be gone. They'll effectively be whole new cities. I don't see why that renewal can't coexist with a gradual move inland. Not starting from scratch, just putting new development slightly more on the landward side of the city than before.

[tsimionescu]

> Since we'll probably continue to have improvements in safety, diseases, etc. between now and 2100, the world should be a safer place for humans by then. So it doesn't make sense for people to worry their kids will suffer a bad world due to climate change. They'll most likely enjoy a better world than us despite climate change.

I am sorry, but this is just delusional. Perhaps the biggest catastrophes will be averted, but only with great effort that our children and grandchildren will have to endure.

[lopmotr]

Quantify these catastrophes and the effort that will be needed to avert them.

Bear in mind that civilization will collapse without the great effort of people doing their jobs and keeping everything working, climate change or not. So great effort is going to happen regardless. It's not a tragedy that people work.