Past and future hydrological drought

In this chapter, we provide an assessment of how to generate reliable data for analysing drought in three key periods; the distant past, the instrumental period and the future, with the overarching aim to better understand drought behaviour across time, including observed trends and future changes. We discuss how to obtain historical records using proxy data (distant past), how to extend observed time series in space and time (instrumental period) and finally, how to generate hydrological time series based on climate projections. We look at difficulties in obtaining long-term records and how uncertainty plays a role in those long-term records. Finally, we look at changes in drought indices (distant past and instrumental period) and the use of climate change projections for future drought characterisation. This chapter can help you to understand the challenges and opportunities that you get when studying past, recent and future droughts.