Humans have caused 1.5 °C of long-term global warming according to new estimates

On the order of 100-200 trillion USD. Which is roughly 100-200% of global yearly GDP. Or 2-5% of yearly GDP until 2050. This could well be provided by printing money at all the federal reserve banks.

This investment will likely bring in a positive return on investment because it reduces the negative climate impacts.

Without such investments the downstream costs in climate change adaptation will be very expensive

There is a demographic conflict of interest between those who will be alive in 2050 and those who will not. The long-term gains are difficult to deny. The short-term costs, however, will be massive.