Novel approaches to quantify the emergence of anthropogenic climate change
Understanding how the climate system will respond to ongoing human interference is a question of profound societal importance. A significant barrier to quantifying the effect of human activity on the climate system is interpreting how the signal of anthropogenic change can be isolated and distinguished from the background noise of internal variability. An emerging framework in the scientific community is now to investigate signal-to-noise ratios as a more effective measure of the impact of human influence on the climate. As the cumulative amount of greenhouse gases emitted by the global population continues to increase, emerging (human-induced) signal-to-noise ratios in temperatures are starting to become clear for highly aggregated spatial and temporal scales. However, some other climate phenomena, such as meteorological drought, exhibit a more complex response to anthropogenic forcings. Identifying how further warming will change the characteristics of such phenomena is therefore more difficult, despite the significant policy implications for both climate adaptation and mitigation. In this thesis, I investigate novel approaches towards separating the relative signal of anthropogenic climate warming from internal variability for these cases of low signal-to-noise ratios. By more effectively understanding the drivers of emergent changes to the climate system, these results help to quantify, and thus communicate, the increasingly damaging effects of human interference on the climate system.