scholarly journals Different Time Windows Provide Divergent Estimates of Climate Variability and Change Impacts on Maize Yield in Northeast China

2019 ◽  
Vol 11 (23) ◽  
pp. 6659 ◽  
Author(s):  
Xi Deng ◽  
Yao Huang ◽  
Wenjuan Sun ◽  
Lingfei Yu ◽  
Xunyu Hu ◽  
...  

Maize is the main crop in Northeast China (NEC), but is susceptible to climate variations. Using county-level data from 1980 to 2010, we established multiple linear regression models between detrended changes in maize yield and climate variables at two time windows—whole-season and vegetative and reproductive (V&R) phases. Based on climate change trends, these regression models were used to assess climate variability and change impacts on maize yield in different regions of NEC. The results show that different time windows provide divergent estimates. Climate change over the 31 years induced a 1.3% reduction in maize yield at the time window of whole-season, but an increase of 9.1% was estimated at the time window of V&R phases. The yield improvement is attributed to an increase in minimum temperature at the vegetative phase when the temperatures were much lower than the optimum. Yield fluctuations due to inter-annual climate variability were estimated to be ±9% per year at the time window of V&R phases, suggesting that the impact of climate variability on maize yield is much greater than climate change. Trends in precipitation were not responsible for the yield change, but precipitation anomalies contributed to the yield fluctuations. The impacts of warming on maize yield are regional specific, depending on the local temperatures relative to the optimum. Increase in maximum temperature led to a reduction of maize yield in western NEC, but to an increase in mid-east part of NEC. Our findings highlight the necessity of taking into account the phenological phase when assessing the climate impacts on crop yield, and the importance of buffering future crop production from climate change in NEC.

2020 ◽  
Author(s):  
Xiaomeng Yin ◽  
Guoyong Leng

<p>Understanding historical crop yield response to climate change is critical for projecting future climate change impacts on yields. Previous assessments rely on statistical or process-based crop models, but each has its own strength and weakness. A comprehensive comparison of climate impacts on yield between the two approaches allows for evaluation of the uncertainties in future yield projections. Here we assess the impacts of historical climate change on global maize yield for the period 1980-2010 using both statistical and process-based models, with a focus on comparing the performances between the two approaches. To allow for reasonable comparability, we develop an emulator which shares the same structure with the statistical model to mimic the behaviors of process-based models. Results show that the simulated maize yields in most of the top 10 producing countries are overestimated, when compared against FAO observations. Overall, GEPIC, EPIC-IIASA and EPIC-Boku show better performance than other models in reproducing the observed yield variations at the global scale. Climate variability explains 42.00% of yield variations in observation-based statistical model, while large discrepancy is found in crop models. Regionally, climate variability is associated with 55.0% and 52.20% of yield variations in Argentina and USA, respectively. Further analysis based on process-based model emulator shows that climate change has led to a yield loss by 1.51%-3.80% during the period 1980-1990, consistent with the estimations using the observation-based statistical model. As for the period 1991-2000, however, the observed yield loss induced by climate change is only captured by GEPIC and pDSSAT. In contrast to the observed positive climate impact for the period 2001-2010, CLM-Crop, EPIC-IIASA, GEPIC, pAPSIM, pDSSAT and PEGASUS simulated negative climate effects. The results point to the discrepancy between process-based and statistical crop models in simulating climate change impacts on maize yield, which depends on not only the regions, but also the specific time period. We suggest that more targeted efforts are required for constraining the uncertainties of both statistical and process-based crop models for future yield predictions. </p>


2016 ◽  
Vol 5 (2) ◽  
pp. 41 ◽  
Author(s):  
Emmanuel Nyadzi

<p>The study examines how farmers’ observations of climate variability and change correspond with 42 years (1970-2011) meteorological data of temperature and rainfall. It shows how farmers in the Northern Region of Ghana adjust to the changing climate and explore the various obstacles that hinder the implementation of their adaptation strategies. With the help of an extension officer, 200 farmers from 20 communities were randomly selected based on their farming records. Temperatures over the last four decades (1970-2009) increased at a rate of 0.04 (± 0.41) ˚C and 0.3(± 0.13)˚C from 2010-2011 which is consistent to the farmers (82.5%) observations. Rainfall within the districts are characterised by inter-annual and monthly variability. It experienced an increased rate of 0.66 (± 8.30) mm from 1970-2009, which was inconsistent with the farmers (81.5%) observation. It however decreased from 2010-2011 at a huge rate of -22.49 (±15.90) mm which probably was the reason majority of the respondents claim rainfall was decreasing. Only 64.5% of the respondents had adjusted their farming activities because of climate variability and change. They apply fertilizers and pesticides, practice soil and water conservation, and irrigation for communities close to dams. Respondents desire to continue their current adaptation methods but may in the future consider changing crop variety, water-harvesting techniques, change crop production to livestock keeping, and possibly migrate to urban centers. Lack of climate change education, low access to credit and agricultural inputs are some militating factors crippling the farmers’ effort to adapt to climate change.</p>


2010 ◽  
Vol 11 ◽  
pp. 59-69 ◽  
Author(s):  
Janak Lal Nayava ◽  
Dil Bahadur Gurung

The relation between climate and maize production in Nepal was studied for the period 1970/71-2007/08. Due to the topographical differences within north-south span of the country, Nepal has wide variety of climatic condition. About 70 to 90% of the rainfall occurs during summer monsoon (June to September) and the rest of the months are almost dry. Maize is cultivated from March to May depending on the rainfall distribution. Due to the availability of improved seeds, the maize yield has been steadily increasing after 1987/1988. The national area and yield of maize is estimated to be 870,166ha and 2159kg/ha respectively in 2007/08. The present rate of annual increase of temperature is 0.04°C in Nepal. Trends of temperature rise are not uniform throughout Nepal. An increase of annual temperature at Rampur during 1968-2008 was only 0.039°C. However, at Rampur during the maize growing seasons, March/April - May, the trend of annual maximum temperature had not been changed, but during the month of June and July, the trend of increase of maximum temperature was 0.03°C to 0.04°C /year.Key words: Climate-change; Global-warming; Hill; Mountain; Nepal; TaraiThe Journal of AGRICULTURE AND ENVIRONMENT Vol. 11, 2010Page: 59-69Uploaded Date: 15 September, 2010


2021 ◽  
Author(s):  
Marthe Montcho ◽  
Elie Antoine Padonou ◽  
Marlise Montcho ◽  
Meshack Nzesei Mutua ◽  
Brice Sinsin

Abstract In West Africa, dairy production plays a vital role in the economy and the wellbeing of the population. Currently, dairy production has become vulnerable due to climate variability. The main objective of this study was to investigate dairy farmers’ perceptions and adaptation strategies towards climate change in West Africa. Individual interview and Focus Group Discussions were conducted among 900 dairy farmers. Descriptive statistics and Chi-square test were used to assess dairy farmers’ perception on climate change. Multiple Correspondence Analysis and hierarchical clustering on principal component analysis were used to access the adaptation strategies of dairy farmers. The results revealed that dairy farmers perceived a decrease in the rainy season and the annual rainfall but an increase of the dry season and the annual temperature that affect their activities. Dairy farmers that fed the cattle mainly with natural pastures, crops residues and agroindustrial by-products in the climate zones of Benin, Burkina Faso and Niger, used as climate change adaptation strategies, transhumance in wetland, animal manure to improve fodder production and quality; plants to improve milk production, milk conservation and to treat animal diseases. They sold milk or produced local cheese with the remaining unsold milk. They use crops residues, mineral supplements, herd size reduction; water supply with community pastoral wells and dams, purchase water. Dairy farmers that mainly invested in fodder production and conservation in the climate zones of Mali, sold milk produced to dairies and cheese production units; used plants to improve milk production, pasteurization for milk conservation and veterinary service for animal care. This study provided relevant information for West African policymakers in designing appropriate policies and programs to assist dairy farmers to improve milk production under climate variability and change.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Divine Odame Appiah ◽  
Felix Asante ◽  
Lois Antwi-Boadi ◽  
Richard Serbeh

Purpose This paper aims to examine elderly smallholder farmers’ perceptions of and adaptation to climate variability and change in the Offinso Municipality, Ghana. Design/methodology/approach This paper used quantitative and qualitative methods. Quantitative data were analyzed with frequencies and chi-square tests, whereas qualitative data were thematically analyzed. Findings The results showed that elderly smallholder farmers’ knowledge of climate variability and climate change were based on their sex, level of formal education and experience in farming. Elderly smallholder farmers adopted both on-farm and off-farm strategies to cope with climate change and variability. The vulnerability of elderly smallholder farmers to climate change calls for social protection mechanisms such as a pension scheme that guarantees access to monthly cash transfers. Such a scheme will ease constraints to livelihood and ensure improved well-being. Originality/value Elderly smallholder farmers have remained invisible in discourses on perceptions and adaptation to climate change despite the surge in number of this category of farmers. This paper therefore represents an attempt to highlight the experiences of elderly smallholder farmers with climate variability and change.


2020 ◽  
Vol 12 (10) ◽  
pp. 4102 ◽  
Author(s):  
Denis Macharia ◽  
Erneus Kaijage ◽  
Leif Kindberg ◽  
Grace Koech ◽  
Lilian Ndungu ◽  
...  

Increasing climate variability and change coupled with steady population growth is threatening water resources and livelihoods of communities living in the Wami-Ruvu and Rufiji basins in Tanzania. These basins are host to three large urban centers, namely Dar es Salaam, Dodoma and Morogoro, with a combined total of more than 7 million people. Increased demand for ecosystem services from the available surface water resources and a decreasing supply of clean and safe water are exacerbating the vulnerability of communities in these basins. Several studies have analyzed climate projects in the two basins but little attention has been paid to identify locations that have vulnerable communities in a spatially-explicit form. To address this gap, we worked with stakeholders from national and local government agencies, basin water boards and the Water Resources Integration Development Initiative (WARIDI) project funded by USAID to map the vulnerability of communities to climate variability and change in the two basins. A generalized methodology for mapping social vulnerability to climate change was used to integrate biophysical and socioeconomic indicators of exposure, sensitivity and adaptive capacity and produced climate vulnerability index maps. Our analysis identified vulnerability “hotspots” where communities are at a greater risk from climate stressors. The results from this study were used to identify priority sites and adaptation measures for the implementation of resilience building interventions and to train local government agencies and communities on climate change adaptation measures in the two basins.


2019 ◽  
Vol 22 (7) ◽  
pp. 6831-6849 ◽  
Author(s):  
Olushola Fadairo ◽  
Portia Adade Williams ◽  
Faridah Sendagire Nalwanga

Abstract In the wake of deepened situations of changing climate, a clear understanding of the perceived impacts and adaptation of climate variability and change on livelihoods of vegetable farmers in Western and Eastern Africa, which is not readily available, is critical for sustainable vegetable production in Africa. Development planning for climate change vulnerability and adaptation assessment was utilised in the study. Using multi-stage sampling procedure, 193 vegetable farmers in selected sites prominent for vegetable production from Uganda, Ghana and Nigeria were used. Data were analysed using descriptive statistics, analysis of variance and linear regression at α0.05. Awareness of climate variability and change was high among most respondents from the three countries, but highest among respondents from Uganda (78.3%). Awareness was highest for long dry spell ($$\bar{x}$$ x ¯  = 1.90) and drought ($$\bar{x}$$ x ¯  = 1.81) and lowest for harmful gas emissions ($$\bar{x}$$ x ¯  = 0.76). Changes in climate variability and trends were perceived to be highest in terms of flood volume/damage caused by flood to farmlands in Nigeria ($$\bar{x}$$ x ¯  = 3.85) and Uganda ($$\bar{x}$$ x ¯  = 5.0), but in terms of increased temperature for Ghana ($$\bar{x}$$ x ¯  = 4.93). Impact of climate-related changes on vegetable farming was high in Ghana (98.3%) and Nigeria (46.6%) but low in Uganda (5.0%). Awareness (β = 0.14), perception (β = 0.15) use of adaptation strategies (β = 0.10) and household size (β = − 0.19) predicted change in perceived impact of climate variability among vegetable farmers. Vegetable farmers in Nigeria, Ghana and Uganda are affected differently by climate variability. Farmers in these countries also have different priorities for adaptation strategies. Locality-specific climate adaptation strategies would help ease farmers burden due to climate change.


Author(s):  
Baljeet Kaur ◽  
Som Pal Singh ◽  
P.K. Kingra

Background: Climate change is a nonpareil threat to the food security of hundred millions of people who depends on agriculture for their livelihood. A change in climate affects agricultural production as climate and agriculture are intensely interrelated global processes. Global warming is one of such changes which is projected to have significant impacts on environment affecting agriculture. Agriculture is the mainstay economy in trans-gangetic plains of India and maize is the third most important crop after wheat and rice. Heat stress in maize cause several changes viz. morphological, anatomical and physiological and biochemical changes. Methods: In this study during 2014-2018, impact of climate change on maize yield in future scenarios was simulated using the InfoCrop model. Average maize yield from 2001-15 was collected for Punjab, Haryana and Delhi to calibrate and validate the model. Future climatic data set from 2020 to 2050 was used in the study to analyse the trends in climatic parameters.Result: Analysis of future data revealed increasing trends in maximum temperature and minimum temperature. Rainfall would likely follow the erratic behaviour in Punjab, Haryana and Delhi. Increase in temperature was predicted to have negative impact on maize yield under future climatic scenario.


2020 ◽  
Author(s):  
José J. Hernandez Ayala ◽  
Rafael Méndez-Tejeda

Abstract. This article analyzes the relationship between off-season tropical cyclone (TC) frequency and climate variability and change for the Pacific and Atlantic Ocean basins. TC track data was used to extract the off-season storms for the 1900–2019 period. TC counts were aggregated by decade and the number of storms for the first six decades (pre-satellite era) was adjusted. Mann-Kendall non-parametric tests were used to identify trends in decadal TC counts and multiple linear regression models (MRL) were used to test if climatic variability or climate change factors explained the trends in off-season storms. MRL stepwise procedures were implemented to identify the climate variability and change factors that explained most of the variability in off-season TC frequency. A total of 713 TCs were identified as occurring earlier or later than their peak seasons, most during the month of May and in the West Pacific and South Pacific basins. The East Pacific (EP), North Atlantic (NA) and West Pacific (WP) basins exhibit significant increasing trends in decadal off-season TC frequency. MRL results show that trends in sea surface temperature, global mean surface temperature, and cloud cover explain most of the increasing trend in decadal off-season TC counts in the EP, NA, and WP basins. Stepwise MLR results also identified climate change variables as the dominant forces behind increasing trends in off-season TC decadal counts, yet they also showed that climate variability factors like El Niño-Southern Oscillation, the Atlantic Multidecadal Oscillation, and the Interdecadal Pacific Oscillation also account for a portion of the variability.


2017 ◽  
Author(s):  
Sangchul Lee ◽  
In-Young Yeo ◽  
Ali M. Sadeghi ◽  
Gregory W. McCarty ◽  
Wells D. Hively ◽  
...  

Abstract. Water quality problems in the Chesapeake Bay Watershed (CBW) are expected to exacerbate under climate variability and change. However, climate impacts on agricultural lands and resultant nutrient loads into surface water resources are largely unknown. This study evaluates the impacts of climate variability and change on two adjacent watersheds in the Coastal Plain of the CBW, using Soil and Water Assessment Tool (SWAT) model. We prepared six climate sensitive scenarios to assess the individual effects of variations in CO2 concentration (590 and 850 ppm), precipitation increase (11 and 21 %) and temperature increase (2.9 and 5.0 °C), and considered the predicted climate change scenario using five general circulation models (GCMs) under the Special Report on Emissions Scenarios (SRES) A2 scenario. Using SWAT model simulations from 2001 to 2014, as a baseline scenario, the predicted water and nitrate budgets under climate variability and change scenarios were analyzed at multiple temporal scales. Compared to the baseline scenario, precipitation increase of 21 % and elevated CO2 concentration of 850 ppm significantly increased stream flow and nitrate loads by 50 % and 52 %, respectively, while, temperature increase of 5.0 °C reduced stream flow and nitrate loads by 12 % and 13 %, respectively. Under the climate change scenario, annual stream flow and nitrate loads showed an average increase of nearly 40 %, relative to the baseline scenario. Differences in hydrological responses observed from the two watersheds were primarily attributed to contrasting land use and soil characteristics. The watershed with larger percent croplands indicated increased nitrate yield of 0.52 kg N ha−1 compared to the one with less percent croplands under the climate change scenario, due to increased export of nitrate derived from fertilizer. The watershed dominated by poorly-drained soils showed a lower increase in nitrate yield than one dominated by well-drained soils, due to a high potential of nitrate loss in surface runoff and enhanced denitrification. To mitigate increased nitrate loads potentially caused by climate change, the enhanced implementation of conservation practices would be necessary for this region in the future. These findings assist watershed managers and regulators as they seek to establish effective adaptation strategies to mitigate water quality degradation in this region.


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