Chunjing Qiu

Chunjing Qiu
Laboratoire des Sciences du Climat et l'Environnement | LSCE · Department of Modelling the Climate and the Biogeochemical Cycles, and their Interactions

PhD

About

31
Publications
13,750
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507
Citations
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September 2012 - July 2015
Peking University
Position
  • Master

Publications

Publications (31)
Preprint
Full-text available
Knowledge of the spatial distribution of the fluxes of greenhouse gases and their temporal variability as well as flux attribution to natural and anthropogenic processes is essential to monitoring the progress in mitigating anthropogenic emissions under the Paris Agreement and to inform its Global Stocktake. This study provides a consolidated synth...
Article
Full-text available
Peatlands at high latitudes have accumulated >400 Pg carbon (C) because saturated soil and cold temperatures suppress C decomposition. This substantial amount of C in Arctic and Boreal peatlands is potentially subject to increased decomposition if the water table (WT) decreases due to climate change, including permafrost thaw‐related drying. Here,...
Article
Full-text available
Dynamics of global wetlands are closely linked to biodiversity conservation, hydrology, and greenhouse gas emissions. However, long-term time series of global wetland products are still lacking. Using a diagnostic model based on the TOPography-based hydrological MODEL (TOPMODEL), this study produced an ensemble of 28 gridded maps of monthly global/...
Article
Full-text available
In support of the global stocktake of the Paris Agreement on climate change, this study presents a comprehensive framework to process the results of an ensemble of atmospheric inversions in order to make their net ecosystem exchange (NEE) carbon dioxide (CO2) flux suitable for evaluating national greenhouse gas inventories (NGHGIs) submitted by cou...
Article
Full-text available
In the global methane budget, the largest natural source is attributed to wetlands, which encompass all ecosystems composed of waterlogged or inundated ground, capable of methane production. Among them, northern peatlands that store large amounts of soil organic carbon have been functioning, since the end of the last glaciation period, as long-term...
Article
Full-text available
Peatlands cover about 3% of the Earth’s surface and are regarded as a vital carbon (C) pool and sink. The formation of peatland is supported by continuously supplied nitrogen (N) but the sources of this N remain unclear. Here, we first review N stocks and the rate they accumulate in peatlands, then we present the sources of N, especially through bi...
Article
Full-text available
Regional land carbon budgets provide insights into the spatial distribution of the land uptake of atmospheric carbon dioxide and can be used to evaluate carbon cycle models and to define baselines for land-based additional mitigation efforts. The scientific community has been involved in providing observation-based estimates of regional carbon budg...
Article
Full-text available
Northern peatlands store 300–600 Pg C, of which approximately half are underlain by permafrost. Climate warming and, in some regions, soil drying from enhanced evaporation are progressively threatening this large carbon stock. Here, we assess future CO2 and CH4 fluxes from northern peatlands using five land surface models that explicitly include re...
Article
Full-text available
Siberia experienced an unprecedented strong and persistent heatwave in winter to spring of 2020. Using bottom-up and top-down approaches, we evaluated seasonal and annual CO2 fluxes of 2020 in the northern hemisphere (north of 30ºN), focusing on Siberia where the pronounced heatwave occurred. We found that over Siberia, CO2 respiration loss in resp...
Article
Full-text available
Several lines of evidence show that northern Africa was considerably wetter and greener than today at ∼6,000 years ago, which is known as the mid-Holocene green Sahara (GS). However, most current models could not reproduce climate in the GS. The importance of wetland feedbacks on sustaining a wetter climate has partially been recognized while large...
Preprint
Full-text available
In the global methane budget, the largest natural source is attributed to wetlands that encompass all ecosystems composed of waterlogged or inundated ground, capable of methane production. Among them, northern peatlands that store large amounts of soil organic carbon have been functioning, since the end of the last glaciation period, as long-term s...
Preprint
Full-text available
In support of the Global Stocktake of the Paris Agreement on Climate change, this study presents a comprehensive framework to process the results of atmospheric inversions in order to make them suitable for evaluating UNFCCC national inventories of land-use carbon dioxide (CO2) emissions and removals, corresponding to the Land Use, Land Use Change...
Article
Full-text available
Water-table drawdown across peatlands increases carbon dioxide (CO2) and reduces methane (CH4) emissions. The net climatic effect remains unclear. Based on global observations from 130 sites, we found a positive (warming) net climate effect of water-table drawdown. Using a machine-learning-based upscaling approach, we predict that peatland water-ta...
Article
Full-text available
When a peatland is drained and cultivated, it behaves as a notable source of CO 2 . However, we lack temporally and spatially explicit estimates of carbon losses from cultivated peatlands. Using a process-based land surface model that explicitly includes representation of peatland processes, we estimate that northern peatlands converted to cropland...
Article
Full-text available
Reliable quantification of the sources and sinks of greenhouse gases, together with trends and uncertainties, is essential to monitoring the progress in mitigating anthropogenic emissions under the Paris Agreement. This study provides a consolidated synthesis of CH4 and N2O emissions with consistently derived state-of-the-art bottom-up (BU) and top...
Article
Full-text available
p>Reliable quantification of the sources and sinks of atmospheric carbon dioxide (CO2), including that of their trends and uncertainties, is essential to monitoring the progress in mitigating anthropogenic emissions under the Kyoto Protocol and the Paris Agreement. This study provides a consolidated synthesis of estimates for all anthropogenic and...
Article
Full-text available
Grasslands absorb and release carbon dioxide (CO2), emit methane (CH4) from grazinglivestock, and emit nitrous oxide (N2O) from soils. Little is known about how thefluxesof these three greenhouse gases, from managed and natural grasslands worldwide, havecontributed to past climate change, or the roles of managed pastures versus natural grass-lands....
Preprint
Full-text available
Reliable quantification of the sources and sinks of atmospheric carbon dioxide (CO2), including that of their trends and uncertainties, is essential to monitoring the progress in mitigating anthropogenic emissions under the Kyoto Protocol and the Paris Agreement. This study provides a consolidated synthesis of estimates for all anthropogenic and na...
Article
Full-text available
Reliable quantification of the sources and sinks of greenhouse gases, together with trends and uncertainties, is essential to monitoring the progress in mitigating anthropogenic emissions under the Paris Agreement. This study provides a consolidated synthesis of CH4 and N2O emissions with consistently derived state-of-the-art bottom-up (BU) and top...
Preprint
Full-text available
Regional land carbon budgets provide insights on the spatial distribution of the land uptake of atmospheric carbon dioxide, and can be used to evaluate carbon cycle models and to define baselines for land-based additional mitigation efforts. The scientific community has been involved in providing observation-based estimates of regional carbon budge...
Article
Full-text available
Resolving regional carbon budgets is critical for informing land-based mitigation policy. For nine regions covering nearly the whole globe, we collected inventory estimates of carbon-stock changes complemented by satellite estimates of biomass changes where inventory data are missing. The net land–atmospheric carbon exchange (NEE) was calculated by...
Article
During the early to middle Holocene, the Sahara received enhanced precipitation and was covered by steppe-like vegetation with a large-scale hydrographic network of lakes, wetlands and fans, which is known as the Green Sahara (GS). However, most coupled land-atmosphere models underestimate the precipitation and vegetation cover, suggesting that cri...
Article
Persistent sinks of atmospheric CO2 in undisturbed peatlands are not included in future projections of the global carbon budget. We aimed to explore possible responses of northern peatlands to future climate change and to quantify the role of northern peatlands in the carbon balance of the Northern Hemisphere. The terrestrial Northern Hemisphere (>...
Article
Full-text available
The importance of northern peatlands in the global carbon cycle has been recognized, especially for long-term changes. Yet, the complex interactions between climate and peatland hydrology, carbon storage, and area dynamics make it challenging to represent these systems in land surface models. This study describes how peatlands are included as an in...
Article
Full-text available
The importance of northern peatlands in the global carbon cycle has recently been recognized, especially for long-term changes. Yet, the complex interactions between climate and peatland hydrology, carbon storage and area dynamics make it challenging to represent these systems in land surface models. This study describes how peatland are included a...
Article
Full-text available
Peatlands store substantial amounts of carbon and are vulnerable to climate change. We present a modified version of the Organising Carbon and Hydrology In Dynamic Ecosystems (ORCHIDEE) land surface model for simulating the hydrology, surface energy, and CO2 fluxes of peatlands on daily to annual timescales. The model includes a separate soil tile...
Article
Full-text available
The high-latitude regions of the Northern Hemisphere are a nexus for the interaction between land surface physical properties and their exchange of carbon and energy with the atmosphere. At these latitudes, two carbon pools of planetary significance – those of the permanently frozen soils (permafrost), and of the great expanse of boreal forest – ar...
Article
Full-text available
Peatlands store substantial amount of carbon, are vulnerable to climate change. To predict the fate of carbon stored in peatlands, the complex interactions between water, peat and vegetations need more attention. This study describes a modified version of the ORCHIDEE land surface model for simulating the hydrology, surface energy and CO2 fluxes of...
Article
Full-text available
Climate change is considered a top threat to biodiversity, but the relative roles of contemporary climate versus the rate of climate change in determining spatial patterns of biodiversity are far from clear. China has a very diverse flora and harbors a high percentage of endemic species, but the mechanisms underlying spatial patterns of plant endem...

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Project (1)
Project
Peatlands are widely present in northern latitudes and especially in permafrost regions. They contain a high carbon stock and are one of the greatest natural sources of methane. Their representation in a climate model is crucial to improve the one of the carbon cycle. Moreover, the contribution of methane peatland emissions remains uncertain. Methane emissions from peatlands strongly depend on the climate and are influenced primarily by temperature and soil moisture. Meanwhile, climate change is particularly severe at these latitudes and leads to thawing permafrost with increasing the active layer depth. This large carbon reservoir may be partially mobilized and emitted as CO2 or CH4, depending on hydrological conditions at the surface. The aim of this project is to represent northern peatlands in the ORCHIDEE land surface model. This development is carried out in the version of the model that incorporates processes in high latitudes such as the soil freezing. Peatlands are represented by a specific hydrological scheme which improves the exchange of energy and water. The difficulty is based on the representation of local peatlands processes across a global climate model. Some biological properties were also considered to represent better vegetation of these environments. This development then allows estimate changes in the hydrology of peatlands due to global warming. Studying the changes in hydrology of peatlands by the end of th 21st century will improve the prediction of future changes in their CH4 emissions. This development work was then applied to determine the evolution of methane emissions. Peatlands are one of the largest natural sources of methane and control more than 70% interannual variability of atmospheric concentration of CH4. Methane emissions result from various physical and biological processes such as methanogenesis and the methanotrophy. To represent these processes, a flux density model, integrated in ORCHIDEE, was adapted for peatlands to estimate their methane emissions. The evolution of these emissions is studied between the early 20th and late 21st centuries under different climate scenarios.