We show how a monopolistic owner of oil reserves responds to a carbon-free substitute becoming available at some uncertain point in the future if demand is isoelastic and variable extraction costs are zero but upfront exploration investment costs have to be made. Not the arrival of this...

...The optimal carbon tax reduces emissions from burning fossil fuel, both in the short and medium run. Furthermore, it brings forward the date that renewables take over from fossil fuel and encourages the market to keep more fossil fuel locked up. A renewables subsidy induces faster fossil fuel...