There could be unintended consequences of ambitious efforts to stem the depletion of non-renewable groundwater resources in the North China Plain (see also E. K. White Nature 566, 326; 2019). The plan is to recharge groundwater, limit extraction and impose water-conservation measures. Recharging must be gradual, however, if it is not to incur risks. In our experience, rapid recharging can cause groundwater tables to rise by more than 20 metres within a few weeks.

Such a rise could create sudden stress changes in soil formations, threatening buildings and infrastructure. The water could be exposed to the pervasive organic contaminants and heavy metals that have polluted China’s soils over the past half-century (Nature 566, 26–29; 2019). Also, carbon in soil is a major terrestrial source of carbon dioxide and is sensitive to moisture changes.

In our view, the North China Plain project needs cautious stewardship to offset these risks. It should involve the Ministry of Ecology and Environment (the body responsible for groundwater quality and adapting to climate change), alongside the other ministries that are co-sponsoring the action plan.