A longstanding assumption in environmental and agricultural policy is that ecosystem conservation and food production are fundamentally at odds — protecting grasslands means fewer resources for farming, and expanding cropland comes at the expense of natural ecosystems. This trade-off framing has shaped policy debates from sub-Saharan Africa to the North China Plain. In a new study published in Nature Climate Change, we challenge this assumption and provide causal evidence that large-scale grassland restoration can, in fact, increase crop yields — through a mechanism that has received surprisingly little attention: local climate regulation.

The Policy Context: China's Grassland Ecological Conservation and Reward Program

China's Grassland Ecological Conservation and Reward Program (GECP) is one of the world's largest ecosystem restoration initiatives. Launched in 2011, the program pays herders to reduce livestock numbers and restore degraded grasslands across China's vast pastoral regions. By 2016, it had expanded from 66 to 242 counties. The program has been well-studied for its effects on grassland vegetation and herder livelihoods, but its potential spillover effects on neighboring agricultural areas had not been systematically evaluated.

This gap motivated our study. China's spring maize belt — one of the country's most important food production zones — sits adjacent to the restored grassland areas in northern China. If grassland restoration alters local climate conditions, could those changes affect maize production downstream?

Identification Strategy: Staggered Difference-in-Differences

The core empirical challenge in answering this question is endogeneity. Grassland restoration does not happen randomly — it is concentrated in ecologically degraded, climatically vulnerable, and often economically marginal areas. A naive comparison of counties with and without restoration would conflate the effects of the program with the underlying characteristics of the places where it was implemented.

We exploit the staggered rollout of the GECP — the fact that different counties entered the program at different times between 2011 and 2016 — as a source of quasi-experimental variation. Using a county-level panel dataset spanning 2001 to 2020, we implement a staggered difference-in-differences design that compares treated counties to not-yet-treated counties at the time of policy adoption. Pre-treatment parallel trends are confirmed empirically, and we conduct a battery of robustness checks, including placebo tests, alternative control group definitions, and checks for spatial spillovers.

Results: Climate Effects and Yield Gains

Our findings reveal a clear and internally consistent chain of effects. Grassland restoration reduced average growing-season temperatures (May–September) by approximately 0.1°C and increased cumulative precipitation by 11.48 mm in adjacent spring maize counties. These changes are modest in absolute terms but meaningful in agricultural context: under RCP4.5 projections, northern China's spring maize zone is expected to warm by 0.5–1.5°C over the next two decades, with a reduction in precipitation of around 25 mm. The cooling effect attributable to grassland restoration thus offsets between 7 and 20 percent of projected warming.

These climate effects translated into significant yield gains. We estimate that the GECP increased average maize yields by 7.76 percent (0.437 tonnes per hectare) and reduced yield loss risk by 25.9 percent. The mechanism analysis points to three interacting pathways: a reduction in extreme heat days (harmful degree days fell by 5.57°C·d), an extension of the reproductive growth period by 0.93 days due to reduced heat stress, and increased precipitation during critical growth stages — particularly in July.

The pattern of results is internally consistent with the hypothesized mechanism. Effects are concentrated during the maize growing season and are strongest in the months and growth stages where heat and drought stress are most consequential. Counties with more extensive grassland restoration show larger effects. This heterogeneity lends additional credibility to the causal interpretation.

Reframing the Conservation–Food Security Trade-off

The broader implication of our findings is conceptual as much as empirical. The conservation–food security relationship has often been framed as a zero-sum trade-off: land devoted to ecological restoration is land unavailable for food production. Our results suggest this framing is incomplete. Ecosystem restoration can generate positive agricultural externalities through biophysical channels — in this case, local climate regulation — that are not captured when evaluating conservation programs in isolation.

This has practical implications for how we assess the costs and benefits of large-scale restoration programs. If yield co-benefits are systematically excluded from cost-benefit analyses, the social returns to conservation may be substantially underestimated. Our back-of-envelope calculations suggest the aggregate maize yield gains attributable to GECP are economically significant at the national scale.

At the same time, our findings do not imply that conservation is costless. The GECP achieves grassland restoration in part by reducing livestock numbers, which imposes real income losses on herding households. Understanding how to design policies that simultaneously protect ecosystems, support food security, and maintain herder livelihoods remains an important and unresolved challenge.

Implications Beyond China

The mechanism we document — grassland restoration moderating local temperatures and precipitation through changes in surface energy balance, evapotranspiration, and albedo — is not China-specific. Similar dynamics are plausible wherever degraded grasslands sit adjacent to rain-fed agricultural zones: the Sahel, the American Great Plains, the Loess Plateau, and the margins of the Amazon. Nature-based solutions have long been advocated on ecological grounds; our study adds to a growing body of evidence that they may also carry significant agricultural co-benefits that are worth accounting for in policy design.

Reference

Liu, M., Huang, K., Wang, J., Liu, P., & Wuepper, D. (2026). Grassland restoration increases crop yields through local climate regulation. Nature Climate Change. https://doi.org/10.1038/s41558-026-02663-4