All right. Let’s get sciencey.
The main climatic changes in geologic history are driven by how the earth moves around the sun, how it wobbles on its axis, and how it wobbles on its path. These are called the Milankovitch Cycles. These cycles tell us when the Earth will be in an ice age or an interglacial period, like clockwork.
Many, many other things push the climate to change that are less predictable—if there is too much, or too little, of one greenhouse gas, which can happen when a ginormous volcano erupts and belches tons of CO2 and debris into the atmosphere. Events like this can change the clockwork of the Milankovitch Cycles.
Currently we’re in an interglacial period. This means that we should steadily be getting colder. But this changed when humans went through industrialization and started pumping CO2 into the atmosphere by combusting fossil fuels.
What is CO2? Its official name is carbon dioxide, which is a greenhouse gas, a part of the greenhouse effect.
The atmosphere on earth is made of gases. If we didn’t have this atmosphere, the earth would be an ice ball. The greenhouse gases (CO2, Methane, Water, and a few others) radiate heat. When the sunlight goes through the atmosphere, it warms and excites the gases, which in turn release heat like sitting near a fire. This layer of gas keeps some of the sunlight that is reflected off the earth in the atmosphere.
A thicker layer means more gases to radiate heat, and make it harder for sunlight to escape back into space–the temperature on earth rises.
CO2 levels are rising, and it’s not because of a volcano.