How much should a new gas boiler cost?

It's not just the concrete. Other materials also need to be extracted, produced, processed, and transported.

Not entirely serious:
Concrete has about 590kg CO2 per ton of concrete.
Life expectancy is currently 78.6 years for men and 83.4 years for women.
Per child 58 tons CO2 per year.
For boys = 7,726.77 tons of concrete
For girls = 8,198.64 tons of concrete

You could definitely build a basement with that :p

Appetizing argumentation.

But why stop at unborn and children?

What do you conclude from the fact that the CO2 footprint of adults is probably even higher? And of adults in First World countries even higher? And then significantly (!) higher among the wealthy of these countries?

That alone is a reason to build a mausoleum.

Have I drawn a conclusion? I have not.
Likewise, I cannot/will not/may not/should not give individual groups etc. a CO2 budget or discourage having children.

I had already written earlier that childless people harm the environment less than people with children (58 tons of CO2 per child per year).
That does not mean that childless people could not take further precautions, but their footprint is simply smaller.
The missionaries here in the forum who have a single-family house and children should keep that in mind.
They put their desire to have children above climate protection (this decision is their good right). Additional CO2 must still be saved.
Why should others compensate for that?

In the extreme case that already mentioned, the footprint would really be almost irrelevant.
The Earth would certainly recover over millions of years. But that is, of course, purely theoretical nonsense.

Oh come on, you can compensate for a small extra amount of concrete by being childless :rolleyes:

Unfortunately, I can't manage the extra concrete. I wouldn't know a legal way to become childless again :P Black humor aside - I find the house vs. children discussion completely pointless. Having offspring and thus preserving the species is, in my opinion, the primary purpose of all life. I have nothing against people who decide against having children, but once we start converting people into CO2 numbers, it just becomes absurd. The reason why a child means X amount of CO2 is ultimately still due to our (accustomed) lifestyle. Before we started digging up and burning dead dinosaurs in the industrial age, people had children for thousands of years with a CO2 footprint of 0, just like the adults.

I agree with you on some points.
However, species preservation does not mean overpopulation or population growth but a population adapted to the habitat.
As you correctly wrote, emissions also depend on lifestyle.
On average, every person is converted into CO2, not just children. That's just how it is.
It was also not about house vs. children. Everyone who wants to should build a house and have children if that is their wish. But then please do not raise the green finger (I do not mean the thumb).
Insisting that others compensate for selfishness is questionable.

I find the suggestion to refer to a heat pump here quite justified. It’s a forum, and if so far only the gas boiler has been mentioned, it’s legitimate to point out a heat pump. To simply label it as nonsense (or something like that, I don’t remember the exact wording from page 1) is not entirely fair. There are many families (including us) already heating with an air-to-water heat pump. And we saw the writing on the wall and signed an electricity supply contract with a fixed price until the end of 2022 at the end of 2021. We currently heat our house for less than €54 per month – for heating, hot water, and ventilation. No gas boiler can manage that with current gas prices. Besides, with gas you are extremely dependent on the countries supplying it. And currently, our reserves are so low that it even makes headlines in the media.

Regarding China/Xi doing nothing against CO2 emissions: As little as I like or want to defend the Chinese regime and their human rights practices, much of what is said about it is simply wrong. I can warmly recommend the blog by "Graslutscher." He has written a very detailed article on China and climate change. It takes half an hour to read, but it is excellently prepared, well-founded with many sources, and very interesting.

You will be surprised, however, when you compare the consumption of gas heating systems as an investment against your own consumption and investment...

We heat over 200 m² with a room temperature >24°C. Monthly gas consumption €75. Hot water naturally included...

If you deduct the photovoltaics on your side, it will be even more for you monthly. How many m² and what room temperature?