Global drought trends and future projections

Abstract

Drought is one of the most difficult natural hazards to quantify and is divided into categories (meteorological, agricultural, ecological and hydrological), which makes assessing recent changes and future scenarios extremely difficult. This opinion piece includes a review of the recent scientific literature on the topic and analyses trends in meteorological droughts by using long-term precipitation records and different drought metrics to evaluate the role of global warming processes in trends of agricultural, hydrological and ecological drought severity over the last four decades, during which a sharp increase in atmospheric evaporative demand (AED) has been recorded. Meteorological droughts do not show any substantial changes at the global scale in at least the last 120 years, but an increase in the severity of agricultural and ecological droughts seems to emerge as a consequence of the increase in the severity of AED. Lastly, this study evaluates drought projections from earth system models and focuses on the most important aspects that need to be considered when evaluating drought processes in a changing climate, such as the use of different metrics and the uncertainty of modelling approaches. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.

OsαCA1 Affects Photosynthesis, Yield Potential, and Water Use Efficiency in Rice

“…Accumulating evidence is suggesting that chloroplasts not only carry out photosynthesis but also produce various metabolites and participate in plant responses to adverse conditions [ 56 , 57 ]. Our observations that OsαCA1 is located in chloroplasts ( Figure 1 C) and that OsαCA1 deficiency significantly restricted plant growth and reduced WUE ( Figure 2 C,F and Figure 3 A–G) suggest the importance of OsαCA1 functions in plants’ adaptation to adverse conditions, especially drought, which has been a prime challenge for plant life since it moved onto land and one that will likely worsen if climate change continues [ 58 ]. Thus, we are currently generating transgenic lines that overexpress the OsαCA1 gene to further explore how OsαCA1 affects yield potential and plant responses to water limitation.…”

Climate change impacts on spatial and seasonal meteorological drought characteristics for the island of Ireland

“…Our research is subject to several limitations. CMIP5 models, upon which the CORDEX ensemble is based, show substantial disagreement compared with observed trends in meteorological droughts, with a tendency to overestimate drying in mid‐to‐high latitudes (Knutson & Zeng, 2018; Vicente‐Serrano et al, 2022a, 2022b). The latest generation of CMIP6 models show better performance in reproducing long‐term precipitation trends (Vicente‐Serrano et al, 2022a, 2022b).…”

An Increasing Effect of Soil Moisture on Semiempirical Water‐Use Efficiency Models From Wet to Dry Climate Regions

“…The present research demonstrates that SWC plays an increasingly significant role in the semiempirical WUE models at the ecosystem scale, transitioning from energy‐limited to water‐limited regions. Despite the ongoing controversy regarding global drought caused by global warming (Cai et al., 2009; Sheffield et al., 2012), the severity of ecological droughts and the associated risk of crop yield reduction is amplified by the coupling of temperature and soil moisture (Lesk et al., 2021; Vicente‐Serrano et al., 2022). Consequently, there are more uncertainties in estimating the impact of radiation on empirical WUE models, especially in arid regions, regardless of SWC.…”