Presumably she's referring to her first proposal -- a carbon tax. It's my understanding that there's nearly consensus among economists that a carbon tax is the most efficient solution to global warming, but political consensus that it would never happen when framed as a tax.
If you don't know what a carbon tax is, or why it's orders of magnitude more efficient a solution than "eat less meat" I'd encourage you to look into it a bit. Essentially if you create a system where what is best for the planet is also the cheapest course of action (for individuals and businesses), you no longer have to rely on convincing every single individual to change their morality/beliefs.
Instead, it should be paired with a dividend which makes it revenue neutral for the median household. Lower income families, who are more impacted by but less responsible for climate change, would be paid a benefit.
I'm not sure how these two ideas make sense in your head. If you implement a carbon tax and the rich are the greatest contributors as you stated, one would expect them to be hit by the carbon tax as well.
In any case, I personally see an income tax as a strange thing to have in the context of a discussion wherein taxing undesirable behavior is seen as a way of disincentivizing it.
At the very minimum free the working class and lower-middle class from income tax.