evidence: Climate models are complex because of the all the elements that are in flux within Earth’s systems. If our atmosphere was like the moon’s, climate modeling would be fairly easy because the moon barely has an atmosphere. On Earth, climate scientists must account for temperature fluctuations, wind patterns, ocean currents, land surface characteristics and much more. Because of this, the models always consider some level of uncertainty – but models measuring smaller areas with higher resolutions produce more accurate models. Despite a small amount of uncertainty, scientists find climate models of the 21st century to be pretty accurate because they are based on well-founded physical principles of earth system processes. This basis solidifies the confidence of the scientific community that human emissions are changing the climate, which will impact the entire planet.