A Dutch family doctor called Tibor Poelmann posted a petition on an online forum for GPs in 2021. He wanted their pension fund to stop investing in oil and gas. It quickly gathered 1,200 signatures. Three years later the fund, which looks after €10 billion (£8.4 billion) for 25,000 doctors, decided to sell all its fossil fuel investments. The push came from the doctors themselves, through a council of GPs elected by the fund’s members.