Changes in terrestrial water storage (TWS) are a critical indicator of freshwater availability. We use NASA GRACE/GRACE-FO data to show that the continents have undergone unprecedented TWS loss since 2002. Areas experiencing drying increased by twice the size of California annually, creating “mega-drying” regions across the Northern Hemisphere. While most of the world’s dry/wet areas continue to get drier/wetter, dry areas are now drying faster than wet areas are wetting. Changes in TWS are driven by high-latitude water losses, intense Central American/European droughts, and groundwater depletion, which accounts for 68% of TWS loss over non-glaciated continental regions. “Continental drying” is having profound global impacts. Since 2002, 75% of the population lives in 101 countries that have been losing freshwater water. Furthermore, the continents now contribute more freshwater to sea level rise than the ice sheets, and drying regions now contribute more than land glaciers and ice caps. Urgent action is required to prepare for the major impacts of results presented.

Strengthening the resilience of societies to extreme weather events is an urgent and critical priority around the world. Extreme weather often causes population displacement that compromises human security. Environment-induced displacement is multifaceted because climate extremes, population, and socio-economic conditions, among other factors, converge to influence individuals’ decisions to move. When large-scale, catastrophic floods occur, people tend to move both suddenly and rapidly for survival. Quantifying the patterns and mechanisms of such displacement at global scale is essential to support areas at high risk for climate-induced displacement. Here we present the global distribution of vulnerability to floods by mapping potential flood exposure and observed flood-induced displacement. We found that countries in Africa might be highly vulnerable to floods because they have high flood-induced displacement even at low- to mid-level flood exposure. Our results show that income levels (Gross National Income) substantial impact flood-induced displacement. Moreover, the relationship between income levels and displacement is nonlinear, and this nonlinearity indicates large gaps in flood-induced displacement between high- and low-income countries. We suggest that low-income countries, particularly in Africa, face a high likelihood of flood-induced displacement and need to develop adaptation measures to mitigate the potential for displacement and the associated risks.

Coping with climate change in socio-ecological systems is one of the most urgent issues facing the world. This is particularly true in socio-ecological systems, where climate not only influences social and ecosystem dynamics, but also modulates their interaction. In this paper, we presented a conceptual framework through a literature review and a trend analysis for assessing the impact of climate change that incorporates socio-ecological interactions. In particular, we focused on the Mongolian pastoral system, which has tightly coupled socio-ecological interactions, as a model for describing the framework. Our framework suggests that the flexibility in mobility of herders is the principal factor in determining the vulnerability of the socio-ecological system to climate change. The flexibility varies along a climatic gradient and socio-ecological interactions in each region have evolved to be suited to its local climate regime. Herders in northern and central regions of Mongolia move shorter distances, and less flexible, than those in southern (Gobi) region. Climatic hazards, on the other hand have been increasing across Mongolia with a trend toward warmer and drier conditions since the 1960s. We suggest that further warming and drying would have the greatest impact on northern and central regions due to lower flexibility in mobility among herders there coupled with the much higher livestock density in the regions. The findings support that maintaining flexibility of mobile herding will likely be crucial to reducing the vulnerability of the Mongolian pastoral system to climate change.

Seawater desalination is a practical technology for providing fresh water to coastal arid regions. Indeed, the use of desalination is rapidly increasing due to growing water demand in these areas and decreases in production costs due to technological advances. In this study, we developed a model to estimate the areas where seawater desalination is likely to be used as a major water source and the likely volume of production. The model was designed to be incorporated into global hydrological models (GHMs) that explicitly include human water usage. The model requires spatially detailed information on climate, income levels, and industrial and municipal water use, which represent standard input/output data in GHMs. The model was applied to a specific historical year (2005) and showed fairly good reproduction of the present geographical distribution and national production of desalinated water in the world. The model was applied globally to two periods in the future (2011–2040 and 2041–2070) under three distinct socioeconomic conditions, i.e., SSP (shared socioeconomic pathway) 1, SSP2, and SSP3. The results indicate that the usage of seawater desalination will have expanded considerably in geographical extent, and that production will have increased by 1.4–2.1-fold in 2011–2040 compared to the present (from 2.8 × 10⁹ m³ yr⁻¹ in 2005 to 4.0–6.0 × 10⁹ m³ yr⁻¹), and 6.7–17.3-fold in 2041–2070 (from 18.7 to 48.6 × 10⁹ m³ yr⁻¹). The estimated global costs for production for each period are USD 1.1–10.6 × 10⁹ (0.002–0.019 % of the total global GDP), USD 1.6–22.8 × 10⁹ (0.001–0.020 %), and USD 7.5–183.9 × 10⁹ (0.002–0.100 %), respectively. The large spreads in these projections are primarily attributable to variations within the socioeconomic scenarios.