It's frowned upon because the "solutions" to overpopulation are immoral. Over population causing climate change is an idea funded and perpetuated by large companies who do not want to take blame.
If the UK stopped producing carbon emissions tomorrow, I promise it would make an enormous difference: we're the 17th largest CO2 emitter despite having a relatively small population.
This is because: 1) average CO2 consumption of a person varies a lot by lifestyle: living more sustainably does matter, and, 2) the largest contributors to climate change are fuel companies, not individual people: many countries have much smaller carbon footprints (both total and per capita) because of their political choices. The best solution to climate change is political change and climate accountability, especially on the global scale.
hard agree on the siesta idea but instead of 12-3 I'd say stop work at 3-6 instead, or work mornings and evenings (with lots of time in between)
in summer, the hottest part of the day can be 4-6pm (because there's a big lag between the sunniest part of the day and the ground heating up, which then heats the air) - also Spain has a weird timezone (GMT+2 despite being west of us, so their sunrise was 5 mins earlier than ours, but was at 7am local time, and ours was at 5:05am)