Saving the ozone layer required changing practices in a relatively small part of the economy (refrigeration, mostly). In 1994, the total cost of the transition in the US was estimated to less than $100 billion [1], about 1.3% of GDP ($7.3 trillion [2]).

Reducing global carbon emissions to reach net zero by 2050 has been estimated to cost $9.2 trillion per year [3]. World GDP is currently $126 trillion [4]. That means 7.3% of current world GDP per year, or 1.8x of it over a quarter century.

[1] https://cei.org/studies/the-high-cost-of-cool-the-economic-i...

[2] https://www.macrotrends.net/global-metrics/countries/usa/uni...

[3] https://www.mckinsey.com/capabilities/sustainability/our-ins...

[4] https://www.imf.org/external/datamapper/NGDPD@WEO/OEMDC/ADVE...