The ecosystem plays an important role in mitigating global warming through carbon assimilation. In addition, climate change has both positive and negative impacts on ecosystem productivity. To combat climate change, the Paris Agreement has set the goal of limiting global warming well below 2 °C with an ultimate target of 1.5 °C above preindustrial levels. It remains unclear how ecosystem productivity will respond to these warming targets. Here, we project global changes in gross (GPP) and net (NPP) primary productivity under 1.5 °C/2 °C warming using a dynamic vegetation model coupled with a state-of-art climate model. We use site-level observations to validate the present-day simulations and the multimodel ensemble to validate the future projections. We identify the main drivers of ecosystem changes by distinguishing between the impacts of CO₂ fertilization, fast climatic responses to CO₂ radiative perturbation, and slow climatic feedbacks to ocean warming due to the large heat capacity. Compared with the present day, global GPP increases by 11.5% (20.9%) and NPP increases by 14.8% (27.1%) under the 1.5 °C (2 °C) warming scenario with similar magnitudes of change in the tropics and subtropics. Changes in the leaf area index mainly follow those of GPP/NPP but with more significant enhancement in boreal regions. CO₂ fertilization causes the dominant contributions to GPP changes over 83% of land areas. The slow responses to ocean warming cause negative changes in GPP/NPP and partly offset regional CO₂ fertilization over the tropics, where the climate is projected to be drier due to atmosphere-ocean feedback. The fast climatic responses to CO₂ radiative perturbation further decrease GPP/NPP but with a moderate magnitude. The projection suggests that ecosystem productivity will increase in a warmer climate but with large spatial heterogeneity.

生态系统在通过碳同化减缓全球变暖方面发挥着重要作用。此外，气候变化对生态系统生产力既有积极影响，也有消极影响。为了应对气候变化，《巴黎协定》设定了将全球变暖控制在远低于 2°C 的目标，最终目标是比工业化前水平高 1.5°C。目前尚不清楚生态系统生产力将如何应对这些变暖目标。在这里，我们使用动态植被模型和最先进的气候模型来预测在 1.5 °C/2 °C 变暖下全球总初级生产力 (GPP) 和净初级生产力 (NPP) 的变化。我们使用站点级观测来验证当前的模拟和多模式集合来验证未来的预测。我们通过区分 CO 的影响来确定生态系统变化的主要驱动因素₂施肥，对 CO ₂辐射扰动的快速气候响应，以及由于大热容量对海洋变暖的缓慢气候反馈。与当前相比，在 1.5 °C (2 °C) 变暖情景下，全球 GPP 增加了 11.5%（20.9%），NPP 增加了 14.8%（27.1%），热带和亚热带地区的变化幅度相似。叶面积指数的变化主要遵循 GPP/NPP 的变化，但在北方地区增强更为显着。CO ₂施肥导致超过 83% 的土地面积对 GPP 变化的主要贡献。对海洋变暖的缓慢反应导致 GPP/NPP 的负面变化并部分抵消了区域 CO ₂在热带地区施肥，由于大气-海洋的反馈，预计那里的气候将更加干燥。对 CO ₂辐射扰动的快速气候响应进一步降低 GPP/NPP，但幅度适中。该预测表明，生态系统生产力将在气候变暖的情况下增加，但空间异质性较大。