摘要：Climate change will lead to significant changes of groundwater recharge and thus
renewable groundwater resources. Using the global water resources and use model
WaterGAP, the impact of climate change on groundwater recharge and the number of
affected people was computed for four climate scenarios by two climate models.
Vulnerability of humans to decreased groundwater resources depends on both the degree
of decrease and the sensitivity of the human system to the decrease. For each
grid cell, a sensitivity index composed of a water scarcity indicator, an indicator
for dependence of water supply on groundwater and the Human Development
Index was quantified. Combining per cent groundwater recharge decrease with the
sensitivity index, global maps of vulnerability to the impact of decreased groundwater
recharge in the 2050s were derived. In the A2 (B2) emissions scenario, 18.4–19.3%
(16.1–18.1%) of the global population of 10.7 (9.1) billion would be affected by
groundwater recharge decreases of at least 10%, and 4.8–5.7% (3.8–3.8%) of the
global population would be in the two highest vulnerability classes. The highest
vulnerabilities are found at the North African rim of the Mediterranean Sea, in
southwestern Africa, in northeastern Brazil and in the central Andes, which are
areas of moderate to high sensitivity. For most of the areas with high population
density and high sensitivity, model results indicate that groundwater recharge is
unlikely to decrease by more than 10% until the 2050s. However, a fifth to a
third of the population may be affected by a groundwater recharge increase of
more than 10%, with negative impacts in the case of shallow water tables. The
spatial distribution of vulnerability, even at the continental scale, differs more
strongly between the two climate models than between the two emissions scenarios.
