Global warming is a big concern nowadays, and people are trying to find ways to lower carbon emissions. A new kind of market has been created to trade carbon credits, like tokens that show a decrease in CO2 emissions. There are two types of markets: one where companies trade emission allowances set by rules, and the other where they buy credits from projects that lessen emissions. For instance, the Clean Development Mechanism (CDM) helps fund projects that reduce CO2. These markets help companies meet emission targets at lower costs.