Assessment of potential drought hazard in Gansu Province under climate change

Gansu Province, Northwestern China. Accurate prediction of drought evolution is crucial to promote climate change adaptation capabilities. This study evaluated drought evolution during the near-future (2020–2060) and far-future (2061–2100) and explored ecosystem responses under the SSP2–4.5 and SSP5–8.5. In addition, we proposed a new drought hazard index (DHI) that incorporates drought dynamics to assess drought hazard. Droughts are expected to intensify relative to historical conditions, with SSP5–8.5 showing stronger drought trends, while SSP2–4.5 shows more frequent and prolonged droughts. The drought instantaneous recovery speed (IRS) is forecasted to accelerate across all climate scenarios, with the greatest increase in SSP5–8.5, while the instantaneous development speed (IDS) shows a significant rise only under SSP5–8.5. Forests and croplands exhibited relatively lower drought intensity and faster IRS, whereas grasslands, urban, and bare land experienced more frequent and prolonged droughts with slower IRS. Moreover, the responses of IDS and IRS to climatic factors vary among ecosystems, with the IRS of vegetation showing particularly high sensitivity to variations in precipitation and temperature. The results also indicate that the drought hazard level in the northwestern area will further increase in the future, whereas it shows a decreasing trend in the central area. Although the drought hazard level in the southwestern region is relatively low, it is gradually increasing. ● Gansu Province is expected to undergo intensified drought in the future. ● Forest and cropland show higher IDS and IRS, while bare land changes remain stable. ● IRS exhibits greater sensitive to climate variables than IDS under future climate scenarios. ● A novel Drought Hazard Index (DHI) was developed by integrating IDS and IRS.