Acknowledgements

Grateful acknowledgement is made to the following sources:

Figure 1: From Jason Knows Science. This file is licensed under the Creative Commons Attribution Licence https://creativecommons.org/ licenses/ by/ 3.0/.

Figure 3: https://www.carbonbrief.org. This file is licensed under the Creative Commons Attribution Licence Creative Commons — Attribution-NonCommercial-NoDerivatives 4.0 International — CC BY-NC-ND 4.0.

Table 1: Adapted from Columbia University.