Do you have anything to support that claim? Carbon taxes are a theoretically effective mechanism to tilt the markets towards more sustainable means of production, that is something most economists agree on; alas, practically they are often thwarted by caving out exceptions or delays for short-term political gain.
At the moment carbon is still getting subsidizes for 100 billion per year. I'd love it if they taxed it by that amount.
If most economists agree on something, it probably isn't true. Just like every economist agreed that there would be no inflation in 2020.
You probably mean carbon credits, from the EU Emissions Trading System. Wikipedia has a lengthy and well-balanced article on the subject: https://en.wikipedia.org/wiki/European_Union_Emissions_Tradi...
It's an ugly and wasteful system set up instead of other, simpler measure that were politically unacceptable at the time, like higher VAT, excise duties on all fossil fuels across all industries without exception, including fuel oil for heating and aviation fuel.