Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: Burning of fossil fuels, such as oil, releases carbon into the atmosphere. This carbon must be cycled - removed from the atmosphere - back into living organisms, or it stays in the atmosphere. Increased carbon in the atmosphere contributes to the greenhouse effect on Earth. Answer: greenhouse effect
Carbon released by burning fossil fuels contributes to what effect in the atmosphere?