The main way to make money from trees used to be chopping them down and selling them to sawmills. But now, people are getting paid to do the opposite. WSJ’s Ryan Dezember explains the economics of the carbon offset market and why it’s finally taking root. …Carbon offsets … market really started to take off in the last decade when California instituted a cap and trade system. …One reason for that is companies have started making big promises to reduce their carbon footprints. …Companies can’t get rid of all their emissions and all their pollution. So they look for things that will make a negative number on these carbon balance sheets. …For some companies, these kinds of promises help appeal to a growing group of Environmental, Social And Governance (ESG) investors. …One criticism … is you pay a tax so you can feel good about behaving in the same way you always did.