Climate change could intensify Sahel conflicts

Significance It will increase rainfall variability and extreme events such as droughts and floods, as well as raising temperatures. These effects may trigger cascading risks to economic, social and political stability. Impacts The EU could play a key role in moderating climate effects as it shapes migration and security policy in the Sahel. The likelihood and severity of climate impacts will depend on socio-economic and political conditions in the region. Small-scale irrigation, climate-adapted seeds and traditional soil conservation techniques can help increase resilience to climate change.

Upper air circulation and thermal anomalies over India and neighbourhood vis-à-vis Indian summer monsoon activity

The three dimensional circulation and thermal anomaly features associated with droughts and floods India are examined using 20 year of upper wind data over India and neighbourhood. The analysis reveals that years of droughts (floods) in India are associated with cyclonic (anticyclonic) circulation anomalies and cold (warm) thermal anomalies in the troposphere between 500 hPa and 200 hPa over northwestern India. In drought years (flood years) upper tropospheric westerly (easterly) anomalies are observed in the lower latitudes in the months of May and June. Tibetan anticyclone shifted to east of its normal position in drought years , during the month of June. The correlation coefficient between the meridional component of the wind at 200 hPa over northwestern India and the summer monsoon rainfall found to be -0.72 which is significant.

Response Efficacy in Environmental Discounting: Concern and Action towards Climate Change Threats

Extending preceding environmental discounting studies, we examined the role of response efficacy (in low, control, and high conditions) in participants’ valuation of climate-change concern and action across four psychological distance dimensions (temporal, spatial, social, and probabilistic). Participants gave ratings of concern and action in the context of two hypothetical scenarios which were directly related to two different threats (droughts and floods) posed by unmitigated climate change. Rachlin’s hyperboloid discount functions fit the data well. The previously observed gap between concern and action ratings was not replicated in the main analyses, but was seen in the ratings at the minimum distance values. Response efficacy differentially affected ratings of concern and action at the minimum distance values for the temporal, social, and probabilistic dimensions, but differentially affected discount values (k) only for the probabilistic dimension. Compared to their level of concern with the environmental threat, participants who were led to believe that their actions were not efficacious were less willing to engage in mitigation behaviors than participants who were led to believe that their actions were efficacious. The insights gained through the current research effort may be valuable for policymaking as well as intervention design aiming to increase societal mitigation and adaptation efforts.

A novel high-resolution gridded precipitation dataset for Peruvian and Ecuadorian watersheds – development and hydrological evaluation

A novel approach for estimating precipitation patterns is developed here and applied to generate a new hydrologically corrected daily precipitation dataset, called RAIN4PE (for ‘Rain for Peru and Ecuador’), at 0.1° spatial resolution for the period 1981-2015 covering Peru and Ecuador. It is based on the application of a) the random forest method to merge multi-source precipitation estimates (gauge, satellite, and reanalysis) with terrain elevation, and b) observed and modeled streamflow data to firstly detect biases and secondly further adjust gridded precipitation by inversely applying the simulated results of the eco-hydrological model SWAT (Soil and Water Assessment Tool). Hydrological results using RAIN4PE as input for the Peruvian and Ecuadorian catchments were compared against the ones when feeding other uncorrected (CHIRP and ERA5) and gauge-corrected (CHIRPS, MSWEP, and PISCO) precipitation datasets into the model. For that, SWAT was calibrated and validated at 72 river sections for each dataset using a range of performance metrics, including hydrograph goodness of fit and flow duration curve signatures. Results showed that gauge-corrected precipitation datasets outperformed uncorrected ones for streamflow simulation. However, CHIRPS, MSWEP, and PISCO showed limitations for streamflow simulation in several catchments draining into the Paċific Ocean and the Amazon River. RAIN4PE provided the best overall performance for streamflow simulation, including flow variability (low-, high- and peak-flows) and water budget closure. The overall good performance of RAIN4PE as input for hydrological modeling provides a valuable criterion of its applicability for robust countrywide hydrometeorological applications, including hydroclimatic extremes such as droughts and floods.

Real time implementation of agricultural contingency plans to cope with weather aberrations in Indian agriculture

Weather aberrations impact agriculture and allied sectors in one or other parts of the India round the year. Seasonal droughts and extreme weather events in 21st century have caused alarming losses not only in agricultural production but also horticulture, livestock, poultry and fisheries. ICAR-CRIDA, SAUs and DAC, MoA, GoI, prepared more than 580 district level agriculture plans within formation on contingency measures for sustaining higher agriculture production and to cope with extreme events. Real-time contingency planning (RTCP) is being conceptualized and implemented at micro level in farmers’ fields in this country. RTCP implementation during delayed onset of monsoon, seasonal droughts and floods resulted in better crop performance, higher agricultural production, better incomes and overall stability in house-hold livelihoods. In this paper, the real-contingency measures to cope with extreme events for management of horticultural crops, livestock, poultry and fisheries are proposed. Further, the preparedness for RTCP implementation with policy initiatives is also suggested.

Analysis of Drought and Flood Disasters During 0–1950 AD in the Hexi Corridor, China, Based on Historical Documents

It is important to analyze the characteristics of drought and flood change in an arid area over a long timescale for the evolution of the environment. Historical documents were used to reconstruct a drought and flood grade series for the Hexi Corridor from 0 to 1950 AD. The moving average and wavelet transform processing methods were used to determine the temporal evolution characteristics of droughts and floods, as well as the corresponding relationships with climate change and human activities in the Hexi Corridor after 1000 AD. The results showed the occurrence of eight drought phases (370–410 AD, 790–870 AD, 1050–1150 AD, 1260–1340 AD, 1430–1570 AD, 1710–1770 AD, 1800–1890 AD, and 1910–1950 AD), five flood phases (320–360 AD, 1670–710 AD, 1730–1790 AD, 1810–1860 AD, and 1880–1950 AD), and 3 oscillation periods of drought and flood events. Climate change may have been the main factor inducing droughts and floods before 1580 AD, whereas human activities may have increased the frequency of droughts and floods after the 16th century. Therefore, quantifying the impacts of natural factors and human activities on droughts and floods can provide important theoretical guidance for the prevention and reduction of future disasters.

Linkages between GRACE water storage, hydrologic extremes, and climate teleconnections in major African aquifers

Water resources management is a critical issue in Africa where many regions are subjected to sequential droughts and floods. The objective of our work was to assess spatiotemporal variability in water storage and related controls (climate, human intervention) in major African aquifers and consider approaches toward more sustainable development. Different approaches were used to track water storage, including GRACE/GRACE Follow On satellites for Total Water Storage (TWS); satellite altimetry for reservoir storage, MODIS satellites for vegetation indices, and limited ground-based monitoring. Results show that declining trends in TWS (60–73 km3 over the 18 yr GRACE record) were restricted to aquifers in northern Africa, controlled primarily by irrigation water use in the Nubian and NW Saharan aquifers. Rising TWS trends were found in aquifers in western Africa (23–49 km3), attributed to increased recharge from land use change and cropland expansion. Interannual variability dominated TWS variability in eastern and southern Africa, controlled primarily by climate extremes. Climate teleconnections, particularly El Nino Southern Oscillation and Indian Ocean Dipole, strongly controlled droughts and floods in eastern and southern Africa. Huge aquifer storage in northern Africa suggests that the recent decadal storage declines should not impact the regional aquifers but may affect local conditions. Increasing groundwater levels in western Africa will need to be managed because of locally rising groundwater flooding. More climate-resilient water management can be accomplished in eastern and southern Africa by storing water from wet to dry climate cycles. Accessing the natural water storage provided by aquifers in Africa is the obvious way to manage the variability between droughts and floods.

Reservoir regulation affects droughts and floods at local and regional scales

Hydrological extremes can be particularly impactful in catchments with high human presence where they are modulated by human intervention such as reservoir regulation. Still, we know little about how reservoir operation affects droughts and floods, particularly at a regional scale. Here, we present a large data set of natural and regulated catchment pairs in the United States and assess how reservoir regulation affects local and regional drought and flood characteristics. Our results show that (1) reservoir regulation affects drought and flood hazard at a local scale by reducing severity (i.e. intensity/magnitude and deficit/volume) but increasing duration; (2) regulation affects regional hazard by reducing spatial flood connectedness (i.e. number of catchments a catchment co-experiences flood events with) in winter and by increasing spatial drought connectedness in summer; (3) the local alleviation effect is only weakly affected by reservoir purpose for both droughts and floods. We conclude that both local and regional flood and drought characteristics are substantially modulated by reservoir regulation, an aspect that should neither be neglected in hazard nor climate impact assessments.

Climate Change Adaptation Strategies Vary With Climatic Stress: Evidence From Three Regions of Vietnam

Vietnam faces several adverse climatic stresses such as increases in temperature, drought, flooding, saltwater intrusion, and sea-level rise. Past research on climate change adaptation in Vietnam has highlighted that climatic stresses and challenges faced by populations vary across the country. In this study, we are interested to know if autonomous responses also vary, depending on which stress individuals are responding to. To answer this question, we use primary-collected data of 1,306 individuals from the Mekong River Delta, Central Vietnam, and the Red River Delta. Adaptation choices of these individuals are analyzed at two levels: the household-level and the agricultural-level. We estimate multivariate probit models by Geweke-Hajivassilou-Keane (GHK) simulated maximum likelihood methods. Our results show that climate change adaptations vary depending on which stresses individuals are responding to. At the household level, droughts and floods have the strongest effect on climate change adaptation. However, adaptations at the agricultural level depend more on the impacts of the stress and less so on the climatic strss itself. Understanding what climatic stresses are already eliciting a response, and what adaptations are being used by individuals, is invaluable for designing successful climate change policies. This understanding can also help policymakers identify where gaps exist in individual climate change adaptations and fill these gaps with a public response.