Direct Observations Confirm that Humans are Throwing Earth's Energy Budget Off Balance.
A simplified animation of Earth's planetary energy balance: A planet’s energy budget is balanced between incoming (yellow) and outgoing radiation (red). On Earth, natural and human-caused processes affect the amount of energy received as well as emitted back to space. This study filters out variations in Earth’s energy budget due to feedback processes, revealing the energy changes caused by aerosols and greenhouse gas emissions.
Earth is on a budget – an energy budget. Our planet is constantly trying to balance the flow of energy in and out of Earth’s system. But human activities are throwing that off balance, causing our planet to warm in response.
Radiative energy enters Earth’s system from the sunlight that shines on our planet. Some of this energy reflects off of Earth’s surface or atmosphere back into space. The rest gets absorbed, heats the planet, and is then emitted as thermal radiative energy the same way that black asphalt gets hot and radiates heat on a sunny day. Eventually this energy also heads toward space, but some of it gets re-absorbed by clouds and greenhouse gases in the atmosphere. The absorbed energy may also be emitted back toward Earth, where it will warm the surface even more.
Adding more components that absorb radiation – like greenhouse gases – or removing those that reflect it – like aerosols – throws off Earth’s energy balance, and causes more energy to be absorbed by Earth instead of escaping into space. This is called a radiative forcing, and it’s the dominant way human activities are affecting the climate.