Widespread negative impact of daytime warming on vegetation productivity

Gross primary productivity (GPP) is crucial for driving carbon cycle processes and mitigating climate change. Daytime and nighttime warming both suppress GPP, albeit in distinct regions. Considering the varied magnitude of daytime and nighttime warming, it remains unclear whether the decline in GPP will be exacerbated. Here, we employ satellite observations and model simulations to analyze century-scale diurnal temperature patterns, thereby evaluating the responses of GPP to diurnal asymmetrical warming. We identify a reversed asymmetrical warming pattern characterized by intensified daytime warming since the 1980s. Driven by the alterations of the warming pattern, adverse effects of daytime warming on GPP rapidly expanded during 1982–2016, especially in arid regions. Overall, our study underscores a rapid shift of dominance from nighttime to daytime warming, posing a significant threat to vegetation productivity. It has significant implications for understanding the broader impacts of climate change.