Carbon trading is a good way to reduce emissions. Any way we can reduce emissions is good because the more carbon in the air is, the worse the climate gets. We should do anything in our power to get carbon out of the atmosphere, which is why we should stay in the RGGI! The RGGI's proceeds also go towards a variety of good causes, like investing in clean and renewable energy, and making the energy system we have more efficient. There's no good reason to leave the RGGI.

(If you want to see how cool the RGGI is for yourself, they have a handy dandy factsheet here: https://www.rggi.org/sites/default/files/Uploads/Fact%20Sheets/RGGI_101_Factsheet.pdf)