The climate crisis is as much a fact as it is that humans are its main cause. The observed changes in the climate system are the result of human activity, in particular the continued burning of coal, oil and gas. Continued greenhouse gas emissions lead to further global warming. Changes in all components of the climate system make it even more likely that the consequences for Earth's societies and ecosystems will be fundamental and irreversible. To understand this, let's look at how our climate system works and at the basis of our current economy.