globalsecurityreview.com
They're not good suggestions. Low population doesn't lead to progress. It can give you stasis, but we had better be prepared for a significantly lower quality of life. On a most basic level, you don't need railroads for a bunch of disconnected farmers. The suggestions that the way forward to resolve global warming is by shrinking population are all essentially reactionary in nature. We, as a civilization, need a way forward not a way back.This link discusses nuclear weapons and climate change. As per the last paragraph it is a reductio absurdum essay. Nevertheless there are some interesting suggestions about population.
The Climate Change Consequences of Nuclear Weapons — Global Security Review
Deterrence
Yep as per the author..."reductio ad absurdum or, as Jonathan Swift called it, satire, to make a point". WRT population expansion, it is a problem and even more so if everyone wants a 25% carbon footprint of that of NA. Also, lets face it, nuclear weapons are here to stay. No member of the current nuclear club are ever going to give them up.
If both population & living standards grow, it's hard to see how we could keep CO2 emissions down.
Higher living standards do result in lower birth rates and it's likely that if we can bump up living standards in developing countries, we can stabilize the population number.
The ugly reality is that we're past the point of stabilizing anything. Population is shrinking and will continue to shrink, and it's going to cause problems.
It was an example of the problems caused by a shrinking population. To solve this problem in a way that isn't simply regress we need a growing population, not a shrinking one. There are future technologies and efficiencies that won't come to be if the population isn't there to make them worthwhile. An earth of 20 billion people will colonize the moon and mine the asteroid belt. An earth of 500 million won't need to do any of those.
www.healthdata.org
The trend already there for sometime. Urbanisation already in high level, and if we see Japan practical their population are centralised in Metropolitan and Urban area. While rural area is emptying fast. Even Indonesian Java, where 150+ millions and growing, as most populated Island in the world, some rural area begin shown population decline.
As in everything else on human history, going to space depends on economic incentives. If the economic incentives is there, the tech will going to find ways on taking that direction.
I was under the impression that the oceans were the real lungs.
IIRC the oceans account for about half of the oxygen generation/conversion from CO2, so that Amazon rainforest is not as important, but it still captures and converts a significant amount of carbon, with trees and rainforests accounting for some 28% of the oxygen. If the Amazon were to be clear cut, it would likely trigger even further and greater extreme weather events.
www.nasa.gov
www.britannica.com
There's a lag. Population does not stop growing as soon as the birth rate drops to replacement. Previous higher rates are baked in to the age structure. Until the cohorts born when fertility was higher have worked their way up the population pyramid, turning it into a column with a pyramid at the top, growth can continue, especially if life expectancy increases. The statisticians at the UN, World Bank etc. understand this, & that's why they predict, based on current trends, world population to reach 9.7 billion by 2050 & to possibly peak around 10.4 billion.
I don't believe we are heading for 10 billion. Global birth rates have shrunk to 2.3 birth per woman. Basic population replenishment is 2.1 and the rates have been on a steady downward trend. Developed countries suffer from this more then any others, where in many countries the importation of migrants is seen as a solution to the issue of having enough workers. At the extreme end places like South Korea and Japan, some of the more prosperous, developed, and industrialized nations, are actively dying out. You'll note the world bank data cuts off at 2021. However the decreases are definitely continuing.
The Lancet: Dramatic declines in global fertility rates set to transform global population patterns by 2100 | Institute for Health Metrics and Evaluation
By 2050, over three-quarters of countries will not have high enough fertility rates to sustain population size over time. This will increase to 97% of countries by 2100.
I don't know if we will shrink to 500 million. It was a bit of an arbitrary figure. But there are technologies that only make sense at scale and improvements that only become necessary with a growing population. We have a definite situation where developed countries dip into a negative population growth trend. And we have more and more countries becoming developed over time. Now maybe development will stop or even rollback. Or maybe something will emerge to get developed countries birth rates up. But as it stands, I believe we're heading for a significant population decline in much of the world, possibly all of the world in a forseeable future. I think right now shrinking populations are a bigger problem then growing populations.
As for 20 billion and the earth's carrying capacity, I think this is overblown. We can't all drive SUVs and live in suburbs with massive commutes, but with reasonable urban planning, good public transit, and an effort to invest in things like renewables and nuclear energy, the carrying capacity of the earth is far larger then 10 billion. There are many reasons for why the current carbon footprint is as large as it is that have to do with economic choices and lifestyles rather then direct quality of life issues.
But it also works in the other direction. It means that many populations that are still growing are doing so on this rising life expectancy, and ultimately are set up to shrink. I guess it remains to be seen how this plays out. We seem to be on the cusp of a major word, possibly a third world war. The demographic damage from just the Russo-Ukrainian war is already measurable.
I'm saying it's possible. Whether it happens or not is another story. And it's not just politicians campaigning against measures to mitigate climate change. There's a reason so many western countries have virtually destroyed their nuclear power industries. Not the wisest of moves.
I think this is where technology come in and efficiencies of scale come in. A larger population in my opinion is better able to live in a prosperous society then a smaller one. Again, it only makes sense to build railroads if the population is there. It only makes sense to build high-speed rail if even more population is there. Russia is a great case study in this, where they were looking to copy European high-speed rail developments, but then did some math and realized it would only pay for itself on a handful of routes like Moscow-St. Petersburg, St. Petersburg-Helsinki, and Moscow-Berlin. Even Moscow-Kazan was questionable and still hasn't been put up. For other directions there isn't a customer base to afford the high speed rail. You need a larger population to build certain things, without which those things won't be worth while.
ourworldindata.org
Losing the permafrost could trigger several potentially quite nasty issues. IIRC in some areas of the permafrost there are trapped pockets of methane gas and it had been theorized that should permafrost which has trapped one of these pockets were to melt, the gas could get released and end up back in the atmosphere, where it would be anohter/more 'greenhouse' gas. It is also my understanding that in portions of the Russian Far North, there have been some new and rather mysterious craters which have appeared in the ground, which have been theorized to have been caused by some of these trapped gas pockets getting released as the ground warmed.