Causes of Climate Change The main cause of climate change is global warming and it has multiple negative consequences on physical, biological and human systems, among other effects. Lets start by the beginning. The greenhouse effect is a natural process that allows the Earth to maintain the necessary conditions to support life: the atmosphere retains part of the Sun's heat; Without the greenhouse effect, the average temperature of the planet would be minus 18ºC. The atmosphere is made up of various gases that, in the right proportion, fulfill their mission. The problem is when human activities increase the emission of greenhouse gases into the atmosphere and it retains more heat than necessary, causing the average temperature of the planet to increase and what we popularly call global warming to occur.