Energy
According to this UN article, Renewable Energy, Powering a Safer Future,"Energy is at the heart of the climate challenge – and key to the solution."
A big part of the problem comes from how we produce energy. When we burn fossil fuels like coal, oil, and gas to make electricity and heat, it churns out a lot of greenhouse gases. These gases wrap around the Earth, trapping heat from the sun. Fossil fuels are the main culprits here, responsible for more than three-quarters of global greenhouse gas emissions and nearly 90% of all carbon dioxide emissions.