I mean.... maybe burning everything down would mitigate climate change. But the collapse of global supply chains would lead to billions losing access to sufficient food, clean drinking water, internet, electricity/modern heating, medicine, etc. We would see mass migrations, war, famine, disease, and ecological devastation, all on a scale never before seen in the history of humanity. Ie, all the things we are trying to stop climate change in order to avoid.

Like, let's say you murder the CEO of Exxon Mobile and light all their facilities on fire. The company vanishes, and everyone is scared to try to fill their niche (this wouldn't happen, btw, they would just beef up security). Now whatever nation you are in has no oil. Immediately, the entire economy based on ICE vehicles grinds to a halt. Food shortages start within days. So do shortages of critcial medicines. Rural people are forced to decide between scratching a living off the land or abandoning their homes. All production of new plastics stops. Everyone who used to drive a car now spends hours more commuting each day. Everyone involved in oil and gas loses their jobs and start rioting in the streets. Blackouts and brownouts become common as coal and NG plants go offline. People start burning whatever is nearby in order to stay warm. Stressed out moms start murdering each other at the grocery store over rolls of paper towels. Etc.