Drought

Number of papers: 6

A 1,200-year perspective of 21st century drought in southwestern North America — National Academy of the Sciences, 2010; Woodhouse et al.

The authors show that droughts in the SouthWest USA have to be taken seriously and not blamed on human activity: “The severity, extent, and persistence of the 12th century drought that occurred under natural climate variability, have important implications for water resource management. The causes of past and future drought will not be identical but warm droughts, inferred from paleoclimatic records, demonstrate the plausibility of extensive, severe droughts, provide a long-term perspective on the ongoing drought conditions in the Southwest, and suggest the need for regional sustainability planning for the future.”

Past megadroughts in central Europe were longer, more severe and less warm than modern droughts — Nature Communications, Earth and Environment, 2021; Ionita et al.

European droughts during previous sunspot-minimum times were longer and more severe than thought, and “recent drought events (e.g., 2003, 2015, and 2018), are within the range of natural variability and they are not unprecedented over the last millennium.”

Long-term variability and trends in meteorological droughts in Western Europe (1851–2018) — International Journal of Climatology, 2020; Vicente-Serrano et al.

“We analysed long-term variability and trends in meteorological droughts across Western Europe using the Standardized Precipitation Index (SPI). Precipitation data from 199 stations spanning the period 1851–2018 were employed, following homogenisation, to derive SPI-3 and SPI-12 series for each station, together with indices on drought duration and severity. Results reveal a general absence of statistically significant long-term trends in the study domain, with the exception of significant trends at some stations, generally covering short periods. The largest decreasing trends in SPI-3 (i.e., increasing drought conditions) were found for summer in the British and Irish Isles. In general, drought episodes experienced in the last two or three decades have precedents during the last 170·years, emphasizing the importance of long records for assessing change.”

Reconstructions of droughts in Germany since 1500 — combining hermeneutic information and instrumental records in historical and modern perspectives — European Geosciences Union, 2020; Glaser & Kahle

“The reconstructed monthly [data] clearly reveals the annual structures of dryness and wetness. It allows easy identification of dry months and longer periods of dryness and droughts. In total, the synopsis reveals the generally high variability of dryness and wetness through time. Additionally, the time series clearly show that not only summer but also winter precipitation deficits occur.”

The forgotten drought of 1765–1768: Reconstructing and re-evaluating historical droughts in the British and Irish Isles — International Journal of Climatology, 2020; Murphy et al.

“By applying the Standardized Precipitation Index at 12-month accumulations (SPI-12) to the observed and our reconstructed series we re-evaluate historical meteorological droughts. We find strong agreement between observed and reconstructed drought chronologies in post-1870 records, but divergence in earlier series due to biases in early precipitation observations. Hence, the 1800s decade was less drought prone in our reconstructions relative to observations. Overall, the drought of 1834–1836 was the most intense SPI-12 event in our reconstruction for England and Wales. Newspaper accounts and documentary sources confirm the extent of impacts across England in particular. We also identify a major, “forgotten” drought in 1765–1768 that affected the British-Irish Isles. This was the most intense event in our reconstructions for Ireland and Scotland, and ranks first for accumulated deficits across all three regional series. Moreover, the 1765–1768 event was also the most extreme multi-year drought across all regional series when considering 36-month accumulations (SPI-36).”

Assessing changes in US regional precipitation on multiple time scales — Journal of Hydrology, 2019; McKitrick & Christy

“We show that 2000-year proxy-based reconstructions of the Palmer Modified Drought Index for the US Southeast (SE) and Pacific Coast (PC) regions exhibit LTP and reveal post- 1900 changes to be within the range of longer-term natural fluctuations. We also use a new data base of daily precipitation records for 20 locations (10 PC and 10 SE) extending back in many cases to the 1870s. Over the 1901–2017 interval upward trends in some measures of average and extreme precipitation appear, but they are not consistently significant and in the full records back to 1872 they largely disappear. They also disappear or reverse in the post-1978 portion of the data set, which is inconsistent with them being responses to enhanced greenhouse gas forcing. We conclude that natural variability is likely the dominant driver of historical changes in precipitation and hence drought dynamics in the US SE and PC.”