scholarly journals Vegetation Productivity Dynamics in Response to Climate Change and Human Activities under Different Topography and Land Cover in Northeast China

2021 ◽  
Vol 13 (5) ◽  
pp. 975
Author(s):  
Hui Li ◽  
Hongyan Zhang ◽  
Qixin Li ◽  
Jianjun Zhao ◽  
Xiaoyi Guo ◽  
...  
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Northeast China ◽  
Net Primary Productivity ◽  
Future Climate Change ◽  
Vegetation Productivity ◽  
Leading Role ◽  
The Difference ◽  
Productivity Dynamics ◽  
The Impact

Net primary productivity (NPP) is the total amount of organic matter fixed by plants from the atmosphere through photosynthesis and is susceptible to the influences of climate change and human activities. In this study, we employed actual NPP (ANPP), potential NPP (PNPP), and human activity-induced NPP (HNPP) based on the Hurst exponent and statistical analysis to analyze the characteristics of vegetation productivity dynamics and to evaluate the effects of climate and human factors on vegetation productivity in Northeast China (NEC). The increasing trends in ANPP, PNPP, and HNPP accounted for 81.62%, 94.90%, and 89.63% of the total area, respectively, and ANPP in 68.64% of the total area will continue to increase in the future. Climate change played a leading role in vegetation productivity dynamics, which promoted an increase in ANPP in 71.55% of the area, and precipitation was the key climate factor affecting ANPP. The aggravation of human activities, such as increased livestock numbers and intensified agricultural activities, resulted in a decrease in ANPP in the western grasslands, northern Greater Khingan Mountains, and eastern Songnen Plain. In particular, human activities led to a decrease in ANPP in 53.84% of deciduous needleleaf forests. The impact of climate change and human activities varied significantly under different topography, and the percentage of the ANPP increase due to climate change decreased from 71.13% to 53.9% from plains to urgent slopes; however, the percentage of ANPP increase due to human activities increased from 3.44% to 21.74%, and the effect of human activities on the increase of ANPP was more obvious with increasing slope. At different altitudes, the difference in the effect of these two factors was not significant. The results are significant for understanding the factors influencing the vegetation productivity dynamics in NEC and can provide a reference for governments to implement projects to improve the ecosystem.

CERES-Rice model-based simulations of climate change impacts on rice yields and efficacy of adaptive options in Northeast China

2014 ◽  
Vol 65 (12) ◽  
pp. 1267 ◽  
Author(s):  
Wenxiang Wu ◽  
Qian Fang ◽  
Quansheng Ge ◽  
Mengzi Zhou ◽  
Yumei Lin
Keyword(s):  
Climate Change ◽  
Northeast China ◽  
Rice Yield ◽  
Adaptive Strategies ◽  
Future Climate ◽  
Future Climate Change ◽  
Rice Cultivars ◽  
Rice Yields ◽  
The Impact ◽  
Impacts Of Climate Change

Global temperatures are rising, and concerns about the response of agricultural production to climate change are increasing. Adaptation is a key factor that will shape the severity of impacts of future climate change on food production. Based on actual meteorological, soil and agricultural management data at site scale, the CERES-Rice model, combined with the Regional Climate Model (RCM)-PRECIS, was used to simulate both the effects of climate change on rice yields and the efficacy of adaptive options in Northeast China. The impact simulation showed that rice yield changes ranged from +0.1% to –44.9% (A2 scenario) and from –0.3% to –40.1% (B2 scenario) without considering CO2 fertilisation effects. When considering CO2 fertilisation effects, rice yield reductions induced by temperature increases were decreased at all sites. The CO2 fertilisation effects may partly offset the negative impacts of climate change on rice yields. Adaptive option results revealed that the adverse impacts of climate change on rice yields could be mitigated by advancing the planting dates, transplanting mid–late-maturing rice cultivars to replace early-maturing ones, and breeding new rice cultivars with high thermal requirements. Our findings provide insight into the possible impacts of climate change on rice production, and we suggest which adaptive strategies could be used to cope with future climate change, thus providing evidence-based suggestions for government policy on adaptive strategies.

scholarly journals Climate–Carbon Cycle Feedback Analysis: Results from the C4MIP Model Intercomparison

2006 ◽  
Vol 19 (14) ◽  
pp. 3337-3353 ◽  
Author(s):  
P. Friedlingstein ◽  
P. Cox ◽  
R. Betts ◽  
L. Bopp ◽  
W. von Bloh ◽  
...  
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Net Primary Productivity ◽  
Future Climate ◽  
Climate Feedback ◽  
Future Climate Change ◽  
Ocean Carbon Cycle ◽  
Intergovernmental Panel ◽  
Ocean Carbon ◽  
The Impact

Abstract Eleven coupled climate–carbon cycle models used a common protocol to study the coupling between climate change and the carbon cycle. The models were forced by historical emissions and the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A2 anthropogenic emissions of CO2 for the 1850–2100 time period. For each model, two simulations were performed in order to isolate the impact of climate change on the land and ocean carbon cycle, and therefore the climate feedback on the atmospheric CO2 concentration growth rate. There was unanimous agreement among the models that future climate change will reduce the efficiency of the earth system to absorb the anthropogenic carbon perturbation. A larger fraction of anthropogenic CO2 will stay airborne if climate change is accounted for. By the end of the twenty-first century, this additional CO2 varied between 20 and 200 ppm for the two extreme models, the majority of the models lying between 50 and 100 ppm. The higher CO2 levels led to an additional climate warming ranging between 0.1° and 1.5°C. All models simulated a negative sensitivity for both the land and the ocean carbon cycle to future climate. However, there was still a large uncertainty on the magnitude of these sensitivities. Eight models attributed most of the changes to the land, while three attributed it to the ocean. Also, a majority of the models located the reduction of land carbon uptake in the Tropics. However, the attribution of the land sensitivity to changes in net primary productivity versus changes in respiration is still subject to debate; no consensus emerged among the models.

scholarly journals Diazotrophy as a key driver of the response of marine net primary productivity to climate change

2021 ◽  
Author(s):  
Laurent Bopp ◽  
Olivier Aumont ◽  
Lester Kwiatkowski ◽  
Corentin Clerc ◽  
Léonard Dupont ◽  
...  
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Net Primary Productivity ◽  
Climate Model ◽  
Net Primary Production ◽  
Marine Ecosystems ◽  
Anthropogenic Climate Change ◽  
Future Climate Change ◽  
N Fixation ◽  
The Impact

Abstract. The impact of anthropogenic climate change on marine net primary production (NPP) is a reason for concern because changing NPP will have widespread consequences for marine ecosystems and their associated services. Projections by the current generation of Earth System Models have suggested decreases in global NPP in response to future climate change, albeit with very large uncertainties. Here, we make use of two versions of the Institut Pierre Simon Laplace Climate Model (IPSL-CM) that simulate divergent NPP responses to similar high-emission scenarios in the 21st century and identify nitrogen fixation as the main driver of these divergent NPP responses. Differences in the way N-fixation is parameterized in the marine biogeochemical component PISCES of the IPSL-CMs lead to N-fixation rates that are either stable or double over the course of the 21st century, resulting in decreasing or increasing global NPP, respectively. An evaluation of these 2 model versions does not help constrain future NPP projection uncertainties. However, the use of a more comprehensive version of PISCES, with variable nitrogen-to-phosphorus ratios as well as a revised parameterization of the temperature sensitivity of N-fixation, suggests only moderate changes of global-averaged N-fixation in the 21st century. This leads to decreasing global NPP, in line with the model-mean changes of a recent multi-model intercomparison. Lastly, despite contrasting trends in NPP, all our model versions simulate similar and significant reductions in planktonic biomass. This suggests that projected plankton biomass may be a much more robust indicator than NPP of the potential impact of anthropogenic climate change on marine ecosystems across model.

scholarly journals Effects of climate change and human activities on runoff in the Nenjiang River Basin, Northeast China

2012 ◽  
Vol 9 (10) ◽  
pp. 11521-11549 ◽  
Author(s):  
L. Q. Dong ◽  
G. X. Zhang ◽  
Y. J. Xu
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
River Basin ◽  
Human Activities ◽  
Northeast China ◽  
Dominant Factor ◽  
Runoff Reduction ◽  
Nenjiang River Basin ◽  
The Impact

Abstract. The Nenjiang River Basin (NRB) is an important grain-production region with abundant wetlands in Northeast China. Climate change and anthropogenic activities have dramatically altered the spatial and temporal distribution of regional stream discharge and water resources, which poses a serious threat to wetland ecosystems and sustainable agriculture. In this study, we analyzed 55-yr (1956–2010) rainfall and runoff patterns in the river basin to quantitatively evaluate the impact of human activities on regional hydrology. The long-term hydrologic series were divided into two periods: period I (1956–1974), during which minimum land use change occurred, and period II (1975–2010), during which land use change intensified. Kendall's rank correlation test, non-parametric Pettitt test and precipitation-runoff double cumulative curve (DCC) methods were utilized to identify the trends and thresholds of the annual runoff in the upstream, midstream, and downstream basin areas. Our results showed that the runoff in the NRB has continuously declined in the past 55 yr, and that the effects of climate change and human activities on the runoff reduction varied in the upstream, midstream and downstream area over different time scales. For the entire study period, climate change has been the dominant factor, accounting for 69.6–80.3% of the reduction in the total basin runoff. However, the impact of human activities has been increasing from 19.7% during the 1950s–1970s to 30.4% in the present time. Spatially, the runoff reduction became higher from the upstream to the downstream areas, revealing an increasing threat of water availability to the large wetland ecosystem in the lower river basin. Furthermore, the sustainable development of irrigated agriculture in the NRB will be a threat to the survival of the wetlands.

Future climate change risk to forests in China responding to intensified dryness

2020 ◽  
Author(s):  
Yunhe Yin ◽  
Danyang Ma ◽  
Shaohong Wu
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Net Primary Productivity ◽  
Emission Scenario ◽  
General Circulation Models ◽  
Future Climate Change ◽  
Ecosystem Structure ◽  
Dynamic Global Vegetation Model ◽  
Climate Change Risk ◽  
The Impact

<p>Variations in forest net primary productivity (NPP) reflects the combined effects of key climate variables on ecosystem structure and function, especially on the carbon cycle. We performed risk analysis indicated by the magnitude of future negative anomalies in NPP in comparison with the natural interannual variability to investigate the impact of future climatic projections on forests in China. The analysis was conducted mainly based on modifying the Lund–Potsdam–Jena Dynamic Global Vegetation Model, which was driven by five general circulation models (GCMs) simulations. Results from the multi-model ensemble showed that climate change risk of decreases in forest NPP would be more significant in higher emission scenario in China. Under relatively low emission scenarios, the total area of risk was predicted to decline, while for RCP8.5, it was predicted to first decrease and then increase after the middle of 21st century. The rapid temperature increases predicted under the RCP8.5 scenario would be probably unfavorable for forest vegetation growth in the long term. High-level risk area was likely to increase except RCP2.6. The percentage area at high risk was predicted to increase from 5.39% (2021–2050) to 27.62% (2071–2099) under RCP8.5. Climate change risk to forests was mostly concentrated in southern subtropical and tropical regions, generally significant under high emission scenario of RCP8.5, which was mainly attributed to the intensified dryness in south China.</p>

scholarly journals Climate changes during the past 31 years and their contribution to the changes in the productivity of rangeland vegetation in the Inner Mongolian typical steppe

2014 ◽  
Vol 36 (6) ◽  
pp. 519 ◽  
Author(s):  
Xinhong Wu ◽  
Peng Li ◽  
Chao Jiang ◽  
Pengtao Liu ◽  
Jing He ◽  
...  
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Aboveground Biomass ◽  
Human Activities ◽  
Net Primary Productivity ◽  
Annual Production ◽  
Typical Steppe ◽  
The Past ◽  
Grassland Production ◽  
The Impact

The objectives of this study were to explore the impact of climate change and human activities on the annual production of aboveground biomass of vegetation during the past 31 years at a county scale in the typical steppe region of Inner Mongolia. The changes in three banners in the region (Abag Banner, Xilinhaote City, and Xiwuzhumuqin Banner) were analysed. The changes in the annual potential grassland production (net primary productivity) and in the annual production of vegetation, as the sum of aboveground biomass and consumption by livestock, were estimated for each year. A comparison of the changing rates in net primary productivity and aboveground biomass of vegetation over the 31 years was used to distinguish the effects of climate change on grassland production from human activities. The results showed that the climate had become warmer and drier during the past 31 years and thus net primary productivity and annual production of vegetation decreased significantly. Climate change was a major factor for these decreases, while human activities were a minor factor in the decrease of grassland production in Xuwuzhumuqi Banner. The importance of human activities in reducing this decrease in grassland production during the last 31 years is in accordance with the changes in grassland-use policy that has encouraged destocking for grassland restoration in recent years.

scholarly journals Assessing the impact of historical and future climate change on potential natural vegetation types and net primary productivity in Australian grazing lands

2017 ◽  
Vol 39 (4) ◽  
pp. 387 ◽  
Author(s):  
Xiaoni Liu ◽  
Baisen Zhang ◽  
Beverley Henry ◽  
Jinglan Zhang ◽  
Peter Grace
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Carbon Sink ◽  
Natural Vegetation ◽  
Future Climate ◽  
Future Climate Change ◽  
Change Scenario ◽  
Potential Natural Vegetation ◽  
The Impact

The study investigated the impact of historical and future climate changes on potential natural vegetation (PNV) types and net primary productivity (NPP) in Australia, using the Comprehensive and Sequential Classification System model and the Miami model coupled with climate of the 1931–70 and 1971–2010 periods and the projected climate in 2050. Twenty-eight vegetation classes were classified based on the key climate indicators with four of them being the major vegetation classes corresponding to Australian rangelands and accounting for 75% of total land area. There was a substantial shift in areas of vegetation classes from the 1931–70 period to the 1971–2010 period due to the increased rainfall over large areas across Australia. The modelling projected a range of changes in vegetation classes for 2050 depending on the climate-change scenario used. Many vegetation classes with more intense land use (e.g. steppe and forest) were projected to decrease in 2050, which may have significant impact on the grazing industry and biodiversity conservation. By 2050, NPP was projected to increase in central and northern Australia and to decrease in southern and eastern coastal areas and was projected to be higher on average than that of the 1931–70 period. The vegetation classes approximately corresponding to Australian rangelands mostly had increased NPP projections compared with the 1931–70 period. Although actual response will partially depend on human management activities, fire and extreme events, the projected increase in average NPP in 2050 indicates that Australian vegetation, particularly the rangeland vegetation, will likely be a net carbon sink rather than a carbon source by 2050, with the exception of a ‘warm-dry’ scenario.

Impacts of climate change on net primary productivity of grasslands in Inner Mongolia

2014 ◽  
Vol 36 (5) ◽  
pp. 493 ◽  
Author(s):  
Qiuyue Li ◽  
Debao Tuo ◽  
Lizhen Zhang ◽  
Xiaoyu Wei ◽  
Yurong Wei ◽  
...  
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Inner Mongolia ◽  
Net Primary Productivity ◽  
Emission Scenario ◽  
Future Climate ◽  
Future Climate Change ◽  
Emission Scenarios ◽  
The Impact ◽  
A1b Scenario

Net primary productivity (NPP) of grasslands is a key variable for characterising carbon cycles in grassland ecosystems. The prediction of NPP in Inner Mongolia is important for adaptation to future climate change, food security and sustainable use of the grassland resources. The output from two models, potentially suitable for simulating NPP in response to climate change, was tested against observed aboveground forage mass of dry matter at eight sites in Inner Mongolia from 1995 to 2005. The Classification Indices-Based Model (CIBM) showed an acceptable agreement with field measurements. The impact of climate change on the NPP of grasslands was subsequently analysed by CIBM using future climate projections from a Global Circulation Model based on three greenhouse gas emission scenarios: A2 (medium-high emission), A1B (medium emission) and B2 (medium-low emission) differing in assumptions about patterns of global social and economic development. Generally, significant increases in NPP, compared with the baseline NPP of 3.6 tonnes ha–1 for 1961–90, were predicted. The magnitude of the increase in NPP depended on the emission scenario, as well as on the time frame and region considered. Overall the predicted NPP stimulation increased with the level of emissions assumed, being 4.8 tonnes ha–1 in the A2 scenario, 4.3 tonnes ha–1 in the B2 scenario and 4.5 tonnes ha–1 in the A1B scenario in the 2080s (2071–2100). The increase in NPP in response to climate change differed between regions and there was an interaction with emission scenario. For the A2 and the B2 emission scenarios, the western region of Inner Mongolia was predicted to exhibit the strongest NPP increases, but, under the A1B scenario for the 2050s, the south-eastern region exhibited the greatest increase in NPP. It is concluded that the productivity of grassland in Inner Mongolia is likely to increase in response to climate change but these predicted effects are sensitive to emission scenarios and differ regionally. This will provide opportunities but also challenges for herders and policy makers in adapting to this change.

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