LB 14-129 - Attributing the impacts of ecological engineering and climate change on carbon uptake in Northeastern China

In the past decades, several ecological engineering (eco-engineering) programs have been conducted in China, leading to a significant increase in regional carbon sinks. However, the contribution of different eco-engineering programs to carbon uptake is still not clear, as the location of different programs is difficult to identify, and their impacts are concurrent with climate change. We developed a new framework to detect the location of eco-engineering programs by combining a temporal pattern analysis method and Markov model and to attribute the impacts of eco-engineering and climate change on vegetation greenness and carbon uptake by combining a neighbor contrast method within a sliding window and trend analysis on gross primary production (GPP). We applied the framework in Northeastern China during 2000-2020 and identified four main forestry eco-engineering programs: croplands to forest (CtoF), grasslands to forest (GtoF), savannas to forest (StoF), and natural forest conservation (NFC) programs. Both eco-engineering and climate change contributed to the increase in greenness and carbon uptake. Compared to climate change effect, eco-engineering increased GPP by 21.43% on average, with the largest impact observed for CtoF, followed by NFC, GtoF, and StoF, in decreasing order. These findings highlight the important and direct contribution of eco-engineering on vegetation greening with positive effects on carbon sequestration at a fine scale, providing an important implication for eco-engineering planning and management towards a carbon-neutral future.