The Science of Our Changing Climate

This chapter asks two questions, although it is the second which is crucial. You may be tempted to scratch your head: after all, the theme of this book is Our Changing Climate, and we have referred to the rise in atmospheric CO2 content over the past century, and the rise in temperature over the past 75 years, multiple times. So, aren’t these self-answering questions? No. Firstly, scientists do not stop at self-answering questions: they delve deeper. But the key reason is that global average surface temperature is only the most reported evidence of a changing climate. In this chapter we will dive into AR6 in order to find many more indicators of a changing climate. We will also interrogate our CMIP6 simulations to see if we really do understand the science behind such changes. That is to say, how much of the change(s) can we attribute to human actions?