Who said anything about halving it?
I'm simply advocating either a stabilisation or a steady and small reduction. Anything, in fact, that will arrest the ridiculous growth that is currently taking place.
As far as “pensioners starving” is concerned, in developed countries pensions should be funded by the pensioners themselves investing for their retirement. That way there is no dependency on the working population other than for them to ensure that the investments the pension schemes make show a decent return, and this can be easily achieved with a steady or slightly declining population. In the UK all private schemes have, by law, to work like this. It is the State scheme which, for reasons best known to politicians, relies on the current contributions of those working to fund the pensions of those retired. A ridiculous method which should have been tackled years ago.
In “developing” nations this is not an issue as pensions are simply non-existent. All a growing population provides is extra mouths to feed.