Scientists say it’s tied to climate change. That’s the gradual change in Earth’s average temperature and weather patterns.
Climate change happens naturally over time. But most scientists say humans have a lot to do with the current warm-up. For example, we burn fossil fuels. This creates electricity. This also powers our cars. But burning fossil fuels also releases greenhouse gases. These are gases that trap heat in Earth’s atmosphere.
Overall, greenhouse gases are a good thing. Without them, Earth would be too cold for us to survive. The problem is that humans are releasing too many greenhouse gases. This is raising Earth’s average temperature. The past eight years have been the hottest ever recorded.