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Lake surface water temperature (LSWT) is a key parameter in lake energy budget and is highly vulnerable to climate change. However, the long‐term trends in LSWT across China and their driving factors remain uncertain. Here, we used a calibrated lake model to simulate LSWT over 1979–2018 for 91 large lakes (>100 km2) across China. Simulations reveal an overall LSWT warming trend (0.040°C yr−1, p < 0.05), but with large spatial variations. The majority of these lakes show significant warming trends (84%, 0.053°C yr−1), while a significant cooling trend is found in the seven lakes in the northwestern Tibetan Plateau (−0.064°C yr−1). LSWT of approximately 42% of the lakes increases more rapidly than the corresponding ambient air temperature. Regionally, the warming trend is highest for lakes in the Eastern Plain (0.049°C yr−1) and the lowest in the Yunnan‐Guizhou Plateau (0.016°C yr−1). The increases in simulated LSWT also vary across seasons, with a higher rate in winter and spring than in summer and autumn. Changes in air temperature, downward longwave radiation, and wind speed are the most important climatic drivers for LSWT changes. Lake surface warming could be more rapid under future global warming, necessitating greater attention to lake‐atmosphere interactions. Plain Language Summary: Lake surface water temperature (LSWT) is an essential factor in regulating heat and water exchange between lake surface and air. Previous studies have relied on satellite or in situ data to study changes in LSWT at various scales. However, the spatiotemporal variations in LSWT at a national scale and their driving factors are still poorly understood for large countries such as China. Here, we used a one‐dimensional lake model (FLake) to simulate the spatiotemporal variability of LSWT for 91 large lakes (>100 km2) across China from 1979 to 2018. Our simulations reveal a significant warming trend for most lakes, although a few lakes in the northwestern Tibetan Plateau show a cooling trend. Interestingly, 42% (38 of 91) of these lakes showed faster warming rates than nearby air temperatures. LSWT increased faster in spring and winter than in summer and autumn. Lake surface warming is mainly explained by locally rising air temperature, increasing downward longwave radiation, and weakened wind speed. Under the projected warmer climate in the future, lake surface warming is expected to continue, with important implications for lake management and climate change mitigation. Key Points: Lake model revealed a significant annual increase of 0.040°C (p < 0.05) in the surface water temperature of large lakes across China from 1979 to 2018The simulated surface water temperature warmed faster than the local surface air temperature in approximately 42% of the studied lakesChanges in air temperature, downward longwave radiation, and wind speed are the primary contributors to the trends in lake surface water temperature [ABSTRACT FROM AUTHOR]

The Palaeozoic mafic-ultramafic complexes hosting Ni-Cu-Co mineralization occurred discontinuously and coexisted with early Palaeozoic eclogites in the East Kunlun orogenic belt (EKOB), western China. The giant Xiarihamu Cu-Ni-Co sulphide deposit in the EKOB is the largest Cu-Ni-Co sulphide deposit in an orogenic setting in the world. Early Palaeozoic eclogites are distributed as a belt for ca. 530 km in length in the Central Kunlun Zone of the EKOB. The geochronological data, geology and geochemistry of mafic-ultramafic complexes and eclogites in the EKOB are summarized for the tectonic settings of magmatic Cu-Ni-Co mineralization under the Proto- and Paleo-Tethys evolution. The mafic-ultramafic complexes show diverse lithofacies with different formation ages, indicating the multiple stages of long-lived Palaeozoic mantle-derived magmatism in the EKOB. The tectonic location, Neoproterozoic Ocean island basalt (OIB)-like mafic volcanic rocks and eclogite protolith of the EOKB imply the presence of the Neoproterozoic mantle plume magmatism as well as its contribution for enrichments of Ni-Cu-Co beneath EKOB. The ultramafic complexes show a close spatio-temporal relationship with eclogites. The basaltic protoliths of EKOB eclogite were derived from same mantle source as the mafic-ultramafic complexes. A positive correlation of geochronological data between ultramafic complexes with the eclogites in the EKOB is determined and indicated that the mafic magmatism with Cu-Ni-Co mineralization and eclogites were related to the tectonic-magmatic events in process of Proto-Tethys. The ultramafic complexes were formed under the subduction compression and post-collisional extensional settings of the Proto-Tethys and Paleao-Tethys Ocean corresponding to the peak (430–450 Ma) and retrograde (~405–410 Ma) metamorphic periods of eclogites. The Cu-Ni-Co metals were enriched extremely in the stage magma chamber by multi-stage magmatism in EKOB. Therefore, the mafic-ultramafic complexes with a large age span co-occurred with eclogites (especially retrograde eclogites) could be a favourable area for Ni-Co mineralization. [ABSTRACT FROM AUTHOR]

Afforestation is recommended as an effective approach for carbon sequestration and environmental benefits. However, it remains less clear, and sometimes controversial, regarding how afforestation may impact soil inorganic carbon (SIC), a crucial component of the ecosystem carbon pool. Using field data from 619 afforested plots and 163 control plots across northern China, we here investigated the relative and absolute differences in SIC between afforested and corresponding control plots. Our results suggested that afforestation increased SIC in acidic soils, while decreased SIC in alkaline soils. Fitting a linear mixed model and further a structure equation model, we found that afforestation‐induced soil pH change was the most significant factor regulating SIC responses. In particular, SIC was more sensitive to pH change in more arid areas, where both soil pH and SIC stocks were high. Other factors could indirectly affect SIC responses to afforestation through modulating soil pH and soil organic carbon (SOC) dynamics. Moreover, afforestation‐induced SIC changes also varied considerably among different species of tree plantations and across different soil depths. Importantly, in plantations of Pinus sylvestris var. mongholica, Pinus tabuliformis, and Populus spp., changes in SIC caused by afforestation were even comparable to that in SOC. Overall, our findings provide a data‐based understanding on the comprehensive soil carbon dynamics following afforestation and its underlying mechanisms. With the increased use of afforestation and reforestation as nature‐based solutions to climate change, their associated impacts on SIC need to be taken into account, especially in SIC‐rich areas. Key Points: We conducted an extensive field survey investigating the impact of afforestation on soil inorganic carbon (SIC)Soil pH was a key variable mediating SIC responses to afforestation, which enhanced SIC in acidic soils but decreased SIC in alkaline soilsSIC responses to afforestation also showed high variabilities among different species of tree plantations and across soil depths [ABSTRACT FROM AUTHOR]

Market access/potential is main explanations for spatial variation in economic activity. Past research has used quasi-natural experiments such as the imposition and removal of the Iron Curtain to assess how changes in market access influence economic outcomes. Rather, we focus on key quantity effects of market access by tracking population changes induced by the creation of a subnational border. We exploit a quasi-natural experiment in China and use a difference-in-difference identification strategy to estimate the effects of introducing a new border when Sichuan province was split into Chongqing and Sichuan in 1997. We find that the new border had negative population effects on Sichuan counties located near the new border. Further investigation finds that such border effects are unique to the new border region and are not related to other factors such as being more rural. We also provide additional evidence to exclude alternative explanations including differences in industry composition or access to transportation. [ABSTRACT FROM AUTHOR]

There is a large literature examining the effects of agglomeration on income distribution but less is known about its effects in developing countries. In this study, we apply panel data from a microfirm‐level survey and from city‐level data to investigate whether there is a causal relationship between agglomeration and establishment wage dispersion in China. Given the potential endogeneity of city size, we employ an instrumental variable regression approach. We find strong evidence that agglomeration has significant effects on wage inequality in the short and long run. The link between agglomeration and wage inequality is heterogeneous across regions. The spatially varying results appear to be due to different stages of development. Our results are consistent with the sorting models in that it appears that the most productive and least productive firms are relatively thriving in coastal cities, but not inland. [ABSTRACT FROM AUTHOR]

There has been much discussion of the sources of China's growth slowdown but little formal econometric analysis of this question. Chen and Groenewold (2019) show that the slowdown was primarily supply-driven, but they stopped short of identifying specific supply variables. This paper extends their analysis and distinguishes several potential supply components: labor supply, productivity, and capital accumulation. Our results confirm their main conclusion that supply dominates the explanation of the slowdown. A model with two supply factors (labor supply and productivity) reveals that both components contribute to the slowdown, although productivity makes the greater contribution. However, when capital stock is added to the model, the decline in the capital accumulation rate becomes an important factor in the growth slowdown, to some extent replacing the effects of both labor supply and productivity. [ABSTRACT FROM AUTHOR]

Reactive gaseous nitrogen (Ngr) emissions significantly affect Earth's climate system. Disagreement exists, however, over Ngr contributions to short‐ versus long‐term climate forcing, from local to global scales and among different gaseous forms, including NH3, NOx, and N2O. Here, we provide a comprehensive inventory of Ngr from China's croplands based on a new bottom‐up, mass flow‐based approach integrated with fine‐resolution agricultural activity data and nitrogen emission factors. We demonstrate that China's croplands emit about 8.87 Tg N to the atmosphere in 2014. Across different prefectures, Ngr emission per capita conforms to a "Kuznets curve," that is, first increases then decreases, along the gradient of increasing urbanization. Ngr emission per gross domestic productivity (GDP) decreases exponentially with increasing urbanization or per capita GDP. Furthermore, climate change impact analyses suggest that the global‐scale warming effect of China's cropland N2O emissions dominate over local cooling effects ascribed to its NH3 and NOx emissions. Plain Language Summary: Reactive gaseous nitrogen, sourced to the world's highest fertilizer application rates in China, imparts local cooling effects on short time scales. The effects are ultimately counterbalanced by nitrous oxide emissions over the long term, leading to substantial warming effects on the global climate system. We base our conclusion on the first‐ever high‐resolution assessment of reactive nitrogen emissions to the atmosphere from China's croplands. Owing to limited high‐resolution reactive gaseous nitrogen emissions data, hitherto, large uncertainties have existed in the detailing the role of China's cropland reactive gaseous nitrogen emissions on climate forcing. This paucity of information poses a challenge for informing China's agricultural sustainability policies with regard to maintaining/increasing agricultural yields while reduces reactive gaseous nitrogen emissions and their warming potential. Our analyses provide essential information for further sustainable N management and the interactions between agriculture and climate change. We provide policy‐relevant information for mitigation targets, including the 2°C limit goal set by the 2015 Paris Agreement of the United Nations Framework Convention on Climate Change, enabling progress related to multiple United Nations Sustainable Development Goals. Key Points: We provide new high‐resolution estimates of reactive gaseous nitrogen (Ngr) emissions from China's croplands and their seasonal dynamicsAcross different prefectures, Ngr emission per capita follows an environmental Kuznets curve against urbanization rateThe overall warming effect of N2O emissions dominate over local cooling effects ascribed to NH3 and NOx emissions each year [ABSTRACT FROM AUTHOR]

Afforestation in China provides carbon sequestration and prevents soil erosion, but its remote impacts on climate in other regions via the coupling of forest energy fluxes with atmospheric circulation are largely unknown. Here, we prescribe inventory-based forest cover change and satellite-observed leaf area index from 1982 to 2011 in a coupled land-atmosphere model to simulate their biophysical climate effects. Both local and global surface air temperatures show a seasonal contrast in response to past vegetation cover expansion over China: a phenomenon we primarily attribute to a variation of seasonality of vegetation greening. A large cooling in spring results in concurrent decreases in geopotential height over China and zonal wind over Mongolia, causing a dipole structure in the upper troposphere over the Arctic. This accounts for ∼58% of simulated spring warming over the Russian Arctic and ∼61% of simulated spring cooling over the Canadian Artic. Our results imply that spring vegetation dynamics in China may affect climate in northern high latitudes. [ABSTRACT FROM AUTHOR]

Since 2007, China's growth has fallen from around 10% to about 6%–7% per annum. This paper investigates the experience of this slowdown at the provincial level. We use a vector‐autoregressive modelling approach and annual data from 1978 to decompose each province's growth into various factors. We find that (a) all provinces experienced the slowdown; (b) there is considerable variation in this experience across provinces; (c) national factors dominate the provincial slowdown while province‐specific factors explain most of the interprovincial variation; (d) when the national factor is separated into supply and demand components, the supply component dominates. [ABSTRACT FROM AUTHOR]

China’s pension system is in need of comprehensive reform. One measure on which we focus is to increase the retirement age. It is likely that a change in retirement age will have significantly different effects across China’s regions. Interregional disparities are already very substantial in China and it will be important to know how changes in pension arrangements will affect disparities. We consider four policies to increase the retirement age from 60 to 61. They differ according the use made of the extra revenue generated by the policy. All four policies increase welfare and reduce the interregional welfare gap. [ABSTRACT FROM PUBLISHER]

An introduction is presented in which the editor discusses various reports within the issue on topics including volatility of Chinese economic activities, globalization and industrial performance in China, and regional disparities and productivity in China.

China has promised large cuts in CO2 emissions by 2020, which is likely to have differential effects across regions. We know little about the regional effects of pollution reduction. We make a contribution to filling this gap using a small theoretical model with two regions, features of the Chinese economy and the right to emit CO2 as a factor of production. We find regionally differentiated effects on income, welfare and output and explore government policies designed to reduce these effects. The effects of fiscal policies depend crucially on whether one or both regions respond and on whether output or welfare is targeted. Boosts to productive capacity do better in terms of output but not welfare. [ABSTRACT FROM AUTHOR]

Fiscal decentralisation has been an important part of the restructuring of China’s economy over the past three decades. Yet, there has been only limited analysis of the way in which decentralisation in China might affect variables such as welfare, output and income at the aggregate level and none at the regional level. This paper makes a start at filling this gap by analysing the aggregate and regional effects of various policies which aim to change the balance between fiscal activities of the national and regional governments. For this, we use a small theoretical model designed to capture some of the features of the Chinese economy, and we solve it numerically using a parameterisation based on Chinese data. We analyse the effects of four different shocks; all of them involve a transfer of resources to the regional governments financed by a cut in central government expenditure, but they differ in the way in which regional governments use the additional funds: (1) they adjust expenditure on the consumption good, (2) they adjust infrastructure expenditure, (3) they maximise the size of their own budget, and (4) they maximise the welfare of the representative citizen. We find that the aggregate economic effects of decentralisation depend on the precise nature of the policy and that aggregate benefits may often mask a deterioration in the inter-regional distribution of those benefits. [ABSTRACT FROM AUTHOR]

Copyright of Regional Studies is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Despite high economic growth over the past 30 years, China's substantial and persistent regional disparities have been the subject of continuing concern to policy makers, as well as the target of a wide variety of policies. An important issue in the policy debate about whether and how best to attack these disparities is whether measures designed to improve regional equality come at a cost to national development, i.e., whether there is a trade-off between the level of national output and the equality of its distribution across the regions. There is little analysis of this issue in the literature. We help fill this gap by setting up a two-region model designed to capture some of the salient features of the Chinese economy. We subject this model to a number of policy shocks and assess the effects on regional disparities in per capita output, on the one hand, and on aggregate output on the other to investigate the trade-off. We also consider income and welfare as alternatives to output. We find, first, that disparities in per capita output, income, and welfare may move in different directions so that it is important to specify which disparity is being targeted. Second, since both disparities and aggregate outcomes are endogenous, how they move together depends on the nature of the shock driving the model. Thus, some policies designed to reduce disparities face a trade-off and others do not. Only a reduction in internal migration restrictions unambiguously reduces all three disparity measures and increases aggregate output, income, and welfare. All other policies considered face a trade-off in at least one dimension. Third, whether there is a trade-off depends also on the time horizon-some policies face a trade-off in the short run and not in the long run and vice versa. [ABSTRACT FROM AUTHOR]

Copyright of Regional Studies is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Climate warming is likely inducing carbon loss from soils of northern ecosystems, but little evidence comes from large-scale observations. Here we used data from a repeated soil survey and remote sensing vegetation index to explore changes in soil organic carbon (SOC) stock on the Tibetan Plateau during the past two decades. Our results showed that SOC stock in the top 30 cm depth in alpine grasslands on the plateau amounted to 4.4 Pg C (1 Pg=1015 g), with an overall average of 3.9 kg C m−2. SOC changes during 1980s–2004 were estimated at −0.6 g C m−2 yr−1, ranging from −36.5 to 35.8 g C m−2 yr−1 at 95% confidence, indicating that SOC stock in the Tibetan alpine grasslands remained relatively stable over the sampling periods. Our findings are nonconsistent with previous reports of loss of soil C in grassland ecosystems due to the accelerated decomposition with warming. In the case of the alpine grasslands on the Tibetan Plateau studied here, we speculate that increased rates of decomposition as soils warmed during the last two decades may have been compensated by increased soil C inputs due to increased grass productivity. These results suggest that soil C stock in terrestrial ecosystems may respond differently to climate change depending on ecosystem type, regional climate pattern, and intensity of human disturbance. [ABSTRACT FROM AUTHOR]

The article presents information on the housing markets in China. China has developed more rapidly as compared to any other country in the history. A study conduced by Siqi Zheng & colleagues investigated spatial heterogeneity pattern in housing prices is related to the public goods provision of a centralized metropolitan government.

The location and mechanisms responsible for the carbon sink in northern mid-latitude lands are uncertain. Here, we used an improved estimation method of forest biomass and a 5O-year national forest resource inventory in China to estimate changes in the storage of living biomass between 1949 and 1998. Our results suggest that Chinese forests released about 0.68 petagram of carbon between 1949 and 1980, for an annual emission rate of 0.022 petagram of carbon. Carbon storage increased significantly after the late 1970s from 4.38 to 4.75 petagram of carbon by 1998, for a mean accumulation rate of 0.021 petagram of carbon per year, mainly due to forest expansion and regrowth. Since the mid-1970s, planted forests (afforestation and reforestation) have sequestered 0.45 petagram of carbon, and their average carbon density increased from 15.3 to 31.1 megagrams per hectare, while natural forests have lost an additional 0.14 petagram of carbon, suggesting that carbon sequestration through forest management practices addressed in the Kyoto Protocol could help offset industrial carbon dioxide emissions. [ABSTRACT FROM AUTHOR]

Highlights • The 2009/2010 drought in Southwest China has damaged vegetation growth. • Ecosystem impacts by drought vary across space and vegetation types. • Precipitation deficit is the main cause of decreased vegetation growth. • Most of the drought-impacted area could recover within six months from drought. • The carbon flux responses to this drought are poorly captured by models. Abstract The 2009/2010 drought in Southwest China was a "once in a century drought" event. This drought event had strong adverse impacts, such as water scarcity, crop failure, and economic loss, on ecosystems and the human society. Explicit representations of this drought event and associated changes in vegetation dynamics and carbon cycle, however, are still largely missed in literature. Here we used the standardized anomaly of 3-month Standard Precipitation-Evapotranspiration Index (SPEI) to characterize this 2009/2010 drought event, including its onset and end months, duration and severity. We examined the drought impacts on vegetation greenness using Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI); and assessed the terrestrial carbon flux responses to drought using data from satellite-based datasets, atmospheric inversion, one data-based model, and three ecosystem models. Our analysis showed that this "autumn-winter-spring" drought mostly suppressed vegetation growth in Yunnan, North Guangxi, Guizhou and East Sichuan. In comparisons to the same months of the reference period (2000–2015), the drought caused a large reduction in carbon uptake (4.4 ± 5 gCm−2month-1) from the decrease in gross primary production (GPP, 5.7 ± 9.5 gCm−2month-1), although ecosystem respiration (TER) also decreased by a smaller extent (1.3 ± 5.1 gCm−2month-1). Nonetheless, more than 65% of the drought-impacted area recovered in both vegetation greenness and productivity within 3 months, while about 10% of the drought-affected area failed to recover even after 6 months post the drought event. Across different vegetation types, forests and shrubs had stronger capability of drought resistance and shorter post-drought recovery time than crops and grasses. Model comparison reveals that while data from different sources generally agreed on the sign of vegetation greenness and carbon flux responses to drought, they differ significantly in the extent of such responses. [ABSTRACT FROM AUTHOR]

Soil pH is important for controlling many soil properties. The variation in soil pH can be associated with changes in climate, soil buffering system, nitrogen deposition, and plants. However, there still lacks a comprehensive study exploring the effects of all these factors on soil pH simultaneously. Here we aimed to investigate the environmental controls on the spatial variation of soil pH in planted forests across Northern China and reveal its response to different-forms of nitrogen deposition for different species of tree plantations. We sampled 1980 soil profiles from 660 planted forest plots (3 profiles in each plot) in Northern China. We used correlation analyses and structure equation models (SEM) to explore the impacts of multiple environmental factors on soil pH. Climate (water balance, temperature) and soil inorganic carbon accounted for most variations of soil pH. Specifically, the concentration of hydrogen ions ([H+]) varied almost isometrically with soil inorganic carbon, which was also the major buffering system in this region. Nitrogen deposition affected both soil pH values and soil buffering system. Results from structure equation model indicated that nitrate nitrogen directly decreased soil pH, while ammonium nitrogen mostly affected soil pH indirectly through its impacts on soil inorganic carbon. The responses of soil pH to nitrogen deposition were species-specific, and conifer stands tended to have higher soil acidification rate than stands of other tree species. Our study provides important information for understanding mechanisms controlling the spatial pattern of soil pH in planted forests and highlights the need to develop informed policies for soil resource management under increasing threats from anthropogenic nitrogen deposition. • Climate and soil inorganic carbon dominated soil pH variations in planted forests. • Nitrogen deposition indirectly affected soil pH via impacting soil inorganic carbon. • The responses of soil pH to nitrogen deposition were species-specific. [ABSTRACT FROM AUTHOR]

Abstract: Phenological changes are closely related to the carbon cycle of terrestrial ecosystems, and satellite data have been widely used in large scale phenological research. Numerous methods have been developed to reconstruct distinct satellite derived vegetation signals from continuous vegetation index time series and to track the points corresponding to important phenological events. In this study, we perform a multiple-method investigation of the spring vegetation growth onset phenology in temperate China north of 30°N with NDVI (normalized difference vegetation index) data produced from SPOT satellites. The results indicated that the spring onset dates estimated from five different methods show similar spatial pattern along latitudinal or altitudinal gradients, but with significant variances in the dates. In most areas (76% of pixels), the standard deviation (SD) of the estimated spring onset dates from different methods is within one month, while in a few places (2% of pixels), mostly agricultural cropland, the SD is more than 60 days. Comparing the satellite derived green-up onset dates against the gross primary productivity (GPP) time series curves acquired from six eddy covariance towers further highlights the strengths and limits of different methods in estimating phenological events. In a vast region with diverse vegetation types and physical environment, it is critical to choose the “right” method for the “right” place. Generally climate factors such as temperature and precipitation play an important role in controlling the start of vegetation growth in temperate China. Yet this climate-phenology relationship varies largely across different regions and vegetation types. [Copyright &y& Elsevier]

Accurate assessment of the strength of China’s terrestrial ecosystem carbon sink is key to understanding its regional carbon budget. However, large uncertainties in current carbon sink estimations still exist, which hinder the prediction of future climate change trajectories. In this study, we generated a high-resolution (1 km × 1 km) dataset of China’s net ecosystem productivity (NEP) in the last decade via a model tree ensemble approach combined with data from 46 flux sites in China and neighboring regions. The upscaling also included detailed information on nitrogen (N) deposition and forest age that have often been neglected in previous studies. The performance of MTE algorithm in simulating NEP at the site level is relatively high for both training (R 2  = 0.81, RMSE = 0.73 gC m −2  day −1 ) and validation datasets (R 2  = 0.76, RMSE = 0.81 gC m −2  day −1 ). Our data-driven estimation showed that roughly 70% of the area is a carbon sink, and the largest carbon sinks are found in the southeast and southwest monsoon regions. The total annual NEP in China in the last decade was 1.18 ± 0.05 Pg C yr −1 , which is similar to the results found by another foundational global-scale study. Yet, the two studies significantly differ in the spatial distribution of carbon sink density. The seasonality of China’s NEP is characterized by region-specific kurtosis and skewness in most areas. Furthermore, ecosystem carbon use efficiency (CUE), defined as the annual NEP/GPP ratio, also showed high spatial variation. For example, the Xiaoxing’anling and Changbai Mountains in northeastern China, the eastern edge of the Tibetan Plateau, and bordering areas of the southeast and southwest monsoon regions have a larger CUE than the rest of China. On average, China’s terrestrial ecosystem CUE is approximately 0.17. Our data-driven NEP and CUE estimates provide a new tool for assessing China’s carbon dioxide flux. Our study also highlights the necessity to incorporate more environmental variables related to vegetation growth and more data derived from flux sites into NEP upscaling to reduce uncertainties in carbon budget estimations. [ABSTRACT FROM AUTHOR]

Large-scale reforestation can potentially bring both benefits and risks to the water cycle, which needs to be better quantified under future climates to inform reforestation decisions. We identified 477 water-insecure basins worldwide accounting for 44.6% (380.2 Mha) of the global reforestation potential. As many of these basins are in the Asia-Pacific, we used regional coupled land-climate modeling for the period 2041-2070 to reveal that reforestation increases evapotranspiration and precipitation for most water-insecure regions over the Asia-Pacific. This resulted in a statistically significant increase in water yield (p < .05) for the Loess Plateau-North China Plain, Yangtze Plain, Southeast China, and Irrawaddy regions. Precipitation feedback was influenced by the degree of initial moisture limitation affecting soil moisture response and thus evapotranspiration, as well as precipitation advection from other reforested regions and moisture transport away from the local region. Reforestation also reduces the probability of extremely dry months in most of the water-insecure regions. However, some regions experience nonsignificant declines in net water yield due to heightened evapotranspiration outstripping increases in precipitation, or declines in soil moisture and advected precipitation., (© 2022 John Wiley & Sons Ltd.)

There is an increasing food demand with growing population and limited land for agriculture. Conventional agriculture with nitrogen (N) fertilizer applications, however, is a key source of ammonia (NH 3 ) emissions that cause severe haze pollution and impair human health. Organic and conservation agricultural (OCA) practices are thereby recommended to address these dual challenges; however, whether OCA provides cobenefits for both air quality and crop productivity is controversial. Here, we perform a meta-analysis and machine learning algorithm with data from China, a global hotspot for agricultural NH 3 emissions, to quantify the effects of OCA on NH 3 emissions, crop yields and nitrogen use efficiency (NUE). We find that the effects of OCA depend on soil and climate conditions, and the 40-60% substitution of synthetic fertilizers with livestock manure achieves the maximum cobenefits of enhanced crop production and reduced NH 3 emissions. Model forecasts further suggest that the appropriate application of livestock manure, straw return, and no-till could increase grain production up to 59.7 million metric tons (100% of straw return) and reduce maximum US$2.7 billion (60% substitution with livestock manure) in damage costs to human health from NH 3 emissions by 2030. Our findings provide data-driven pathways and options for achieving multiple sustainable development goals and improving food systems and air quality in China.

China has experienced substantial changes in vegetation cover, with a 10% increase in the leaf area index and an ~41.5 million-hectare increase in forest area since the 1980s. Earlier studies have suggested that increases in leaf area and tree cover have led to a decline in soil moisture and runoff due to increased evapotranspiration (ET), especially in dry regions of China. However, those studies often ignored precipitation responses to vegetation increases, which could offset some of the negative impact on soil moisture by increased ET. We investigated 30-year vegetation impacts on regional hydrology by allowing for vegetation-induced changes in precipitation using a coupled land-atmosphere global climate model, with a higher spatial resolution zoomed grid over China. We found high spatial heterogeneity in the vegetation impacts on key hydrological variables across China. In North and Southeast China, the increased precipitation from vegetation greening and the increased forest area, although statistically insignificant, supplied enough water to cancel out enhanced ET, resulting in weak impact on soil moisture. In Southwest China, however, the increase in vegetation cover significantly reduced soil moisture while precipitation was suppressed by the weakened summer monsoon. In Northeast China, the only area where forest cover declined, soil moisture was significantly reduced, by -8.1 mm decade -1 , likely because of an intensified anticyclonic circulation anomaly during summer. These results suggest that offline model simulations can overestimate the increase of soil dryness in response to afforestation in North China, if vegetation feedbacks lead to increased precipitation like in our study.