To ask the natural followup question:
If a Victorian thinker had challenged the appropriateness of medical advances like open heart surgery on the grounds that the Earth was dangerously close to carrying capacity, would you be persuaded that medical researchers were selfish or misguided.
Putting it slightly differently, there's not yet a compelling case that the current average human lifespan or carrying capacity of the planet are set in stone by physical laws. Human science has increased both those numbers many times throughout history.
If you want to make the argument that a counter-factual world with 3 billion humans, all living the American standard of living would be more moral than the current setup, that's a respectable position. But there's substantial difficulty getting from here to there. If we're both wishing for pie-in-the-sky, doesn't it seem more pleasant to wish for the world of 6 billion sustainably American standard of living, and trying to think of how to get to that outcome?
No because life saving procedures are a different matter to procedures that ensure immortality which would effectively cut the death rate in a hypothetical situation where everyone in the world had access to them. My point is I don't think this would be sustainable/ it would lead to dire consequences for the human race. As I mentioned to Mitchell Porter I didn't say that experimentation in this area should be prevented I just think that it is not a desirable road for humanity in the event of success.
If you don't believe in an afterlife, then it seems you currently have two choices: cryonics or permanent death. Now, I don't believe that cryonics is pseudoscience, but it's still pretty poor odds (Robin Hanson uses an estimate of 5% here). Unfortunately, the alternative offers a chance of zero. I see five main concerns with current cryonic technology:
So I wonder if we can do better.
I recall reading of juvenile forms of amphibians in desert environments that could survive for decades of drought in a dormant form, reviving when water returned. One specimen had sat on a shelf in a research office for over a century (in Arizona, if I recall correctly) and was successfully revived. Note: no particular efforts were made to maintain this specimen: the dry local climate was sufficient. It was suggested at the time that this could make an alternative method of preserving organs. Now the advantages of this approach (which I refer to flippantly as "dryonics") is:
There is one big disadvantage of this approach, of course: no one knows how to do it (it's not entirely clear how the juvenile amphibians do it) or even if it would be possible in larger, more complex organisms. And, so far as I know, no one is working on it. But it would seem to offer a much better prospect than our current options, so I would suggest it worth investigating.
I am not a biologist, and I'm not sure where one would start developing such a technology. I frankly admit that I am sharing this in the hope that someone who does have an idea will run with it. If anyone knows of any work on these lines, or has an idea how to proceed, please send a comment or email. Or even if you have another alternative. Because right now, I don't consider our prospects good.
[Note: I am going on memory in this post; I really wish I could provide references, but there does not seem much activity along these lines that I can find. I'm not even sure what to call it: mummification? Probably too scary. Dehydration? Anyway feel free to add suggestions or link references.]