1) The Sun is the primary source of energy for Earth’s climate system.
![Sunlight across the globe: A satellite image shows sunlight gleaming across the surface of the Earth. Sunlight across the globe: A satellite image shows sunlight gleaming across the surface of the Earth.](http://ncse.com/files/images/impacts-index-photo1.jpg)
The first principle is about the Earth’s energy budget: the incoming shortwave energy from the Sun, which is primarily visible light reaching the Earth’s surface, and the longwave outgoing infrared energy that is released from the surface after it has been warmed by the Sun. Small differences in the amount of energy from the Sun reaching the surface of the Earth can alter climate, although small variations in the Sun due to solar cycles are not considered to be the cause of recent warming trends.
Many key misconceptions about climate in general and climate change in particular can be traced back to the complex and often non-intuitive concepts nested in this first principle.
CLEAN’s “Teaching Essential Principle 1” provides overview of the content, why it is important, related pedagogical challenges, and examples of high quality resources by grade level.
Continue to the next section to find out how climate is regulated by complex interactions among components of the Earth system.