Unsettled: What Climate Science Tells Us, What It Doesn’t, and Why It Matters

by Steven E. Koonin

Alas, it then spends about twice as long discussing the then most recent six-year California drought, which that state’s governor had declared over six months before the CSSR was released.26 As you can see from Figure 7.11, which shows the Palmer Drought Severity Index for California since 1901, that six-year drought was at its worst during 2014; by 2019 coverage was of the “wet” winter. It is hard to justify a climate assessment analyzing any “trend” shorter than ten years, even if that makes its conclusions less newsworthy. On longer timescales, the state has moved toward drought since 2000; it remains to be seen whether that will persist in the coming decades.