Australia repeals carbon tax
Australia passed and then repealed a carbon tax in 2014. The tax was at the rate of $22/tonne (USD). Their prime minister called the tax "useless and destructive".
- The California's cap and trade program has a price of $15/tonne
- Carbon capture costs are around $100/tonne, though this is subject to change based on new technology and scale of deployment.
- Estimates on the carbon price needed to prevent the "worst effects" of climate change vary wildly depending on whtatever assumptions are baked into your model. A UN model predicted a price range of $135 to $5,500 / tonne to keep warming below 1.5 degrees C by 2030.