Future Land Use/Land Cover Change Has Nontrivial and Potentially Dominant Impact on Global Gross Primary Productivity

Abstract

Anthropogenic land use/land cover (LULC) change alters terrestrial gross primary productivity (GPP), the largest land‐atmosphere carbon exchanges. Identifying the impacts of LULC changes on future terrestrial GPP has been challenging due to the scarcity of standardized future LULC for ecosystem models. Here, we present eight scenario‐based projections of global spatially explicit LULC at 1‐km resolution over the period 2015–2100 with a Future Land Use Simulation model—consistent with the Shared Socioeconomic Pathways and Representative Concentration Pathways. Twenty computational experiments with different LULC patterns, climate forcing, and CO2 concentrations were conducted to quantify their contributions to future GPP dynamics. Results show that the global terrestrial GPP would decline in the 21st century in most LULC scenarios due to urbanization, agricultural expansion, and deforestation. Moreover, the contribution of LULC changes to global GPP dynamics ranges from 3.43% to 10.78% when CO2 fertilization effect (CFE) is not modeled during 2000–2100 (7%–9% of the terrestrial area is dominated by LULC change). However, this value may range from 10.92% to 16.16% during 2000–2050 and 1.41%–14.57% during 2050–2100. The contribution of LULC even reached 56.08% during 2050–2100 in Southeast Asia due to deforestation. Despite the relatively important role of LULC to GPP dynamics, it becomes trivial globally when incorporating CFE into the model (i.e., LULC accounts for 1.24%–2.51% during 2000–2100). Our findings emphasize the strategic role of CFE in enhancing global GPP and highlight the quantitatively nontrivial role of LULC at the regional scale.

Quantifying the impacts of land cover change on gross primary productivity globally

“…The impacts of land cover changes on the terrestrial carbon cycle have so far mainly been estimated using process-based ecosystem models such as Dynamic Global Vegetation Models or Earth System Models (ESMs) 2 , 8 – 14 . However, there is a large spread in simulated global productivity in these models 15 and no agreement concerning the question of how land cover changes affect ecosystem productivity 8 , 11 , 16 .…”

The turning of ecological change in the Yellow River Basin

“…After the TP, the region witnessed a rise in temperature along with a decline in both precipitation and moderate rain frequency. These climatic conditions contributed to a reduction in soil moisture and the NDVI, but an increase of GPP due to fertilization (Hou et al, 2022). While the central YRB comprises a smaller proportion of cropland, it is important to acknowledge the potential impact of irrigation on soil moisture dynamics (Feng et al, 2016).…”

“…However, in the context of global climate change, vegetation cover has been changing in a complex way in recent decades, and the trend even reverses in some regions (Feng et al, 2021; Jiang et al, 2021; Wang et al, 2011). National policies such as The Grain for Green Program also played a key role in this process (Chen et al, 2016; Hou et al, 2022; Yu et al, 2022). Hence, it is imperative to explore how vegetation greening has transformed in the YRB and to comprehend the causes behind the occurrence of this transformation.…”

“…Over the past decades, vegetation in China absorbed approximately 28%–37% of China's fossil fuel emissions, contributing to a net accumulation of 0.18–0.26 Pg/a of carbon (Piao et al, 2009; Piao et al, 2014). Gross primary productivity (GPP) is the carbon flux fixed in terrestrial ecosystems by organisms (mainly green plants) from the atmosphere through photosynthesis, which can accurately reflect changes in biomass; so it is widely used to assess the carbon storage capacity of ecosystems (Gui et al, 2021; Hou et al, 2022; Zhou et al, 2019). In recent years, a number of studies have investigated carbon exchange between terrestrial ecosystems and atmosphere on hemispheric scale by using GPP, but little attention has been given to the specificity of regional carbon exchange (Tang et al, 2022; Zhang, Gentine, et al, 2022; Zhang, Li, et al, 2022; Zhang, Piao, et al, 2022).…”

“…National policies such as The Grain for Green Program also played a key role in this process (Chen et al, 2016;Hou et al, 2022;Yu et al, 2022). Hence, it is imperative to explore how vegetation greening has transformed in the YRB and to comprehend the causes behind the occurrence of this transformation.…”