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Forests play a pivotal role in regulating climate and sustaining the hydrological cycle. The biophysical impacts of forests on clouds, however, remain unclear. Here, we use satellite data to show that forests in different regions have opposite effects on summer cloud cover. We find enhanced clouds over most temperate and boreal forests but inhibited clouds over Amazon, Central Africa, and Southeast US. The spatial variation in the sign of cloud effects is driven by sensible heating, where cloud enhancement is more likely to occur over forests with larger sensible heat, and cloud inhibition over forests with smaller sensible heat. Ongoing forest cover loss has led to cloud increase over forest loss hotspots in the Amazon (+0.78%), Indonesia (+1.19%), and Southeast US (+ 0.09%), but cloud reduction in East Siberia (-0.20%) from 2002-2018. Our data-driven assessment improves mechanistic understanding of forest-cloud interactions, which remain uncertain in Earth system models. How forests influence cloud cover in different regions is not well understood. Here, the authors use satellite data to show that forests enhance clouds over most temperate and boreal forests but inhibited clouds over forests of Amazon, Central Africa, and Southeast US relative to nonforest areas.

The sediment load of China’s Yellow River has been declining. Analysis of 60 years of runoff and sediment load data attributes this decline to river engineering, with an increasing role of post-1990s land use changes on the Loess Plateau. The erosion, transport and redeposition of sediments shape the Earth’s surface, and affect the structure and function of ecosystems and society 1 , 2 . The Yellow River was once the world’s largest carrier of fluvial sediment, but its sediment load has decreased by approximately 90% over the past 60 years 3 . The decline in sediment load is due to changes in water discharge and sediment concentration, which are both influenced by regional climate change and human activities. Here we use an attribution approach to analyse 60 years of runoff and sediment load observations from the traverse of the Yellow River over China’s Loess Plateau — the source of nearly 90% of its sediment load. We find that landscape engineering, terracing and the construction of check dams and reservoirs were the primary factors driving reduction in sediment load from the 1970s to 1990s, but large-scale vegetation restoration projects have also reduced soil erosion from the 1990s onwards. We suggest that, as the ability of existing dams and reservoirs to trap sediments declines in the future, erosion rates on the Loess Plateau will increasingly control the Yellow River’s sediment load.

Restoring disturbed and over-exploited ecosystems is important to mitigate human pressures on natural ecosystems. China has launched an ambitious national ecosystem restoration program called Grain to Green Program (GTGP) over the last decade. By using remote sensing techniques and ecosystem modelling, we quantitatively evaluated the changes in ecosystem carbon sequestration since China's GTGP program during period of 2000–2008. It was found the NPP and NEP in this region had steadily increased after the initiative of the GTGP program and a total of 96.1 Tg of additional carbon had been sequestered during that period. Changes in soil carbon storage were lagged behind and thus insignificant over the period, but was expected to follow in the coming decades. As a result, the Loess Plateau ecosystem had shifted from a net carbon source in 2000 to a net carbon sink in 2008. The carbon sequestration efficiency was constrained by precipitation and appropriate choices of restoration types (trees, shrubs and grasses) in accordance to local climate are critical for achieving the best benefit/cost efficiency.

Understanding the postprogram land use plans of participants is necessary for the sustainability of the conservation achievements from payments for ecosystem services (PES) programs. Previous studies have analyzed many individual factors affecting participants’ reconversion plans after PES programs. However, whether the regional ecosystem services changes caused by PES programs affect reconversion willingness remains elusive. Here, we used the multilevel linear model to determine the effects of regional ecosystem services changes and individual characteristics on participants’ land reconversion willingness after the Grain for Green Program (GFGP) in the Yanhe watershed of the Loess Plateau. We found that household income, ecological awareness, and employment changes negatively affected reconversion willingness, while nonfarm employment positively affected it at the individual level. At the regional level, the grain production and water yield changes could influence the reconversion willingness of respondents with different individual characteristics. With improved understanding of the factors affecting reconversion willingness, several suggestions to improve the sustainability of the GFGP were proposed. Our study provides a template for analyzing the multilevel factors that affect the sustainability of other PES programs.

Water storage capacity in the layers of canopy, litter, and soil of forest ecosystems has not yet been thoroughly investigated on a global scale. We estimated the global pattern of water storage capacity of forest ecosystems related to water regulation services (WSCFE) in the above three layers based on 1,288 observations and analyzed their 22 controlling environmental factors. The results show that the global mean WSCFE per unit area is 456.7 mm, and the total volume of WSCFE is 22,662.5 km3. Climatic variables are the leading factors contributing to the variations of WSCFE, followed by forest attributes, terrain factors, soil properties, and litter characteristics. This study advances the understanding of the large‐scale variation mechanisms of WSCFE in different forest types and climate zones and provides scientific evidence for ecological protection according to local conditions. Plain Language Summary Forest ecosystem plays a vital role in the earth's hydrological process, and water storage capacity of forest ecosystems related to water regulation service (WSCFE) is of vital importance for human well‐being. Water can be intercepted by forest canopy, be held by litter, and be stored in soils, which accounts for more than a quarter of the water volumes in the terrestrial hydrologic cycle. The WSCFE is affected by many factors and its global pattern has not been well understood. In this study, based on the observed data from literature, we provided a robust global pattern of the WSCFE in canopy layer, litter layer, and soil layer. The results show that the WSCFE in the canopy and soil layer decrease gradually from tropical climate zone to polar climate zone, while the maximum WSCFE in the litter layer appears in polar and cold climate zone. The main controlling factors have different impacts on the WSCFE in the three layers. These should be considered in the developing protection policies for important ecological functional areas. Key Points Forest water storage capacity related to water regulation decreases from equator to pole, from coast to inland, and from mountains to plains Among the controlling factors, climatic factors have the largest and most positive influence on water storage capacity The quantification of three important water storages provides a basis to delineate global water regulation zones

Monoculture plantations have been promoted for the restoration of the world’s forested area, but these have not contained or reversed the loss of biodiversity. More innovative incentive policies should be implemented to shift the planet’s forest restoration policies from increasing the area of forests per se to improving their biodiversity.

Understanding the streamflow‐sediment relationship of large rivers is essential for sustainable basin management. The multi‐temporal scale streamflow‐sediment load coupling regimes, particularly under extreme flood events, remain inadequately understood. This study investigated streamflow‐sediment relationships and hysteresis patterns across annual, monthly, and flood‐event scales in the Yellow River during 1950s–2022, and the correlations between coefficients of streamflow‐sediment relationship were determined. We found that annual streamflow and sediment load generally exhibited a linear relationship, while on the monthly and flood‐event scales, the power‐law sediment rating curves well captured the relationships between discharge (Q) and sediment concentration (SC) (SC = aQb). The streamflow‐sediment relationships on different scales all became weakened over time. Notably, there was stable linear relationships between b and ln(a) in sediment rating curves on both monthly and flood‐event scales, with a consistent slope (around −0.14) over different periods. Further, pronounced hysteresis patterns emerged on both monthly and flood‐event scales, with loops shifted from simple clockwise forms to complex figure‐eight geometries, indicating the shift of sediment supply limitations to enhanced resuspension and altered sediment delivery dynamics. Construction and impoundment of large reservoirs closely coincided with shifts in streamflow‐sediment relationships and hysteresis patterns, with ecological restoration measures further modulating streamflow–sediment dynamics across scales. The findings reveal pronounced nonlinearity in the streamflow–sediment relationship, underscoring the need to account for scale‐sensitive and dynamic sediment transport processes when managing large river systems characterized by high sediment loads and long‐term regulation.

China’s ‘Grain for Green’ revegetation programme has potential to help mitigate climate change. However, the increased water demand in the Loess Plateau is approaching a level that will impact on water availability to meet human demand. Revegetation of degraded ecosystems provides opportunities for carbon sequestration and bioenergy production 1 , 2 . However, vegetation expansion in water-limited areas creates potentially conflicting demands for water between the ecosystem and humans 3 . Current understanding of these competing demands is still limited 4 . Here, we study the semi-arid Loess Plateau in China, where the ‘Grain to Green’ large-scale revegetation programme has been in operation since 1999. As expected, we found that the new planting has caused both net primary productivity (NPP) and evapotranspiration (ET) to increase. Also the increase of ET has induced a significant ( p < 0.001) decrease in the ratio of river runoff to annual precipitation across hydrological catchments. From currently revegetated areas and human water demand, we estimate a threshold of NPP of 400 ± 5 g C m −2  yr −1 above which the population will suffer water shortages. NPP in this region is found to be already close to this limit. The threshold of NPP could change by −36% in the worst case of climate drying and high human withdrawals, to +43% in the best case. Our results develop a new conceptual framework to determine the critical carbon sequestration that is sustainable in terms of both ecological and socio-economic resource demands in a coupled anthropogenic–biological system.

Natural climate solutions (NCS) are strategies for climate mitigation in the land sector that increase carbon storage or avoid GHG emissions. Here we estimate China’s historic NCS mitigation at 0.6 (0.5–0.7) PgCO2e yr−1 (95% CI) during 2000–2020 (8% of fossil CO2 emissions in the contemporary period). Through new NCS activities, the future maximum potential for NCS is projected at 0.6 (0.3–1.0) PgCO2e yr−1 (6% of fossil CO2 emissions) during 2020–2030 and 1.0 (0.6–1.4) PgCO2e yr−1 during 2020–2060. Of the future NCS potentials, 26–31%, 62–65% and 90–91% can be achieved at mitigation costs of US $10, US$ 50 and US$100 (MgCO2e)−1, respectively. Thus, NCS can contribute substantially to China’s Nationally Determined Contributions over the next 10 to 40 years but require a national strategy to reach climate goals and ensure co-benefits for people and nature.Managing natural systems to mitigation climate change is a key strategy for limiting warming. In China, such natural climate solutions could offset 6% of CO2 emissions during 2020–2030, contributing to mitigation goals but highlighting the importance of emissions reductions.

Recent concurrent processes of vegetation greening and reduced resilience (the capacity to recover from disturbances) worldwide have brought many uncertainties into sustainable ecosystems in the future. However, little is known about the conditions and extent to which greening affects resilience changes. Here we assess both vegetation dynamics and resilience in China’s Loess Plateau from 2000 to 2020 using satellite-based vegetation data and an early warning indicator. Our results reveal an overall greening trend in vegetated areas, while resilience shifted from gains to losses at a breakpoint in 2010. Vegetation greening generally contributed to resilience gains, whereas increased temperature and precipitation variability contributed to the resilience loss observed in 2011–2020. These findings provide empirical evidence that vegetation greening does not necessarily correspond to an increase in resilience. We therefore recommend integrating resilience indicators into ecological restoration and conservation efforts to gain a more comprehensive understanding of vegetation states and support effective ecosystem stewardship.