Construction Of Climate-resilient Adaptation Technology System Over The SAGCOT In Tanzania: Climate Risk & System Rice Intensification (SRI)

The impacts of climate-related disasters have recently received increased attention globally.The enhanced climate extremes are considered more deadly than changes in the climate average trend.As being reported in Tanzania,sequential extremes events weaken the resilience of agro-ecosystems and intensify the vulnerability of the agriculture sector,which is predominantly hinged on rain-fed.Unusual floods and heat accompanied by precipitation deficits constitute a significant threat on agricultural sustainability in Tanzania,hampering Tanzania vision 2025.Scientific understanding of the new features of climate change,is a prerequisite to guide development planning and climate change policies.This study adopted a high-resolution multi-modal ensemble from CORDEX-Africa to quantitatively evaluate changes in the probability distribution of annual precipitation and examine the spatial and temporal patterns of the projected extreme precipitation events over Tanzania.RClim Dex software was used to derive the extreme precipitation indices from the bias-corrected multi-modal ensemble for the near future(2026-2050),mid-century(2051-2075)and end of the century(2076-2100)under RCP2.6,RCP4.5 and RCP8.5 scenarios.For the heatwave analysis,the novel Heatwave Magnitude Index daily(HWMId)was adopted to quantitatively distil the scientific evidence and future feature of heatwave occurrence over Tanzania in the baseline period(1983-2012),mid(2041-2070)and end of century(2071-2100)using CHIRTS-daily quasi-global high-resolution temperature dataset and climate simulations from high-resolution multi-modal ensemble of median scenarios(RCP4.5)from CORDEX-Africa.Results of the precipitation analysis revealed that,the indices,R20 mm,R50mm,R9 p,and R99 p,demonstrate remarkable positive changes in the entire country with higher magnitudes in the coastal regions,northeastern highlands(NEH)and southern parts of Tanzania.Though most of the changes are not statistically significant at 5%,there is a general consensus on the trend across the scenarios.However,consecutive wet days(CWD)is projected to decrease ranging from-15% to-33% under all scenarios in central Tanzania from 2026-2100.In the southern parts of Tanzania,changes in CWD could range from-8% to-34% under RCP2.6and RCP8.5 by 2100.Conversely,consecutive dry days,CDD)would increase greater than13% in almost the entire country in future.More importantly,simple daily intensity index(SDII)is projected to increase over the whole country,including areas where total precipitation is projected to decrease,which suggests fewer but heavier rainy days in the future.Unusual floods are likely to be more frequent and intense in the coastal,NEH and southern parts of the country,while the central,western and southern parts of the country would experience lengthy dry spells and much severe drought.The southern part of Tanzania is particularly at flood and drought risk.For the heatwave evaluation,moderate to super extreme heatwaves occurred in Tanzania between 1983 and 2012,particularly in 1999 when ultra-extreme heatwaves(HWMId>32)first hit the country in the study period.This finding differs largely from the EM-DAT reports that never found heatwaves in Tanzania from 1900 to 2021.We also found that,by mid-21 st century,the upper category of HWMId would be hotter and longer,and would occur normally over Tanzania.The spatial extent of all HWMId categories is projected to range from 34% to 73% by the end of the 21 st century with duration ranging from 8 to 35 days relative to 1 to 5 days in the reference period(1983-2012).Hotspots for deadly heatwaves include parts of Lake Victoria basin,extreme edges of southern and southwestern Tanzania,and parts of the coastal stretch.Leaning on the five cascading impact layers due to climate change(average trend,extreme climate events,ecological consequences,socio-economic consequences,and capacity building),this study identified adaptation to “ecological consequences“ as the most relevant impact layer to target since SAGCOT is focusing agriculture,mainly in biophysical level.An adaptation mechanism was then developed,encompassing the relevant interactions between the crop system and the outside environment.“Self-adaptability inspired by outside interventions” is considered the most suitable adaptation pathway that can appropriately address the adaptation challenges within the SAGCOT region.A typical example of this pathway is the Chinese version(modifications)of System Rice Intensification(SRI)methodology,which comprehensively integrates a variety of ecosystems to trigger(inspire)the system(rice)to adjust to its structure and core function in the midst of drought or heatwaves.This study comparatively investigated the SRI methodology in Northeast China and Tanzania and made recommendations for technology transfer to SAGCOT;the most popular,climate-resilient and high-yielding Chinese modifications to the classical SRI package could double rice yield in SAGCOT without compromising environmental quality.These modifications include(1)Triangular geometry of transplanting(2)Rice-duck coculture system(3)System of wheat-rice intensification(4)Plastic cover integrated technology(PCIT),and(5)Direct-seeding SRI.These methodologies,which are very flexible and can be embraced by local farmers in any community,were then adopted in the construction of a climate-resilient adaptation technology system over the SAGCOT region in Tanzania.The main highlights of this study are summarized as follows:1.This study adopted a high-resolution gridded dataset to validate the model simulation capacity on precipitation and temperature.2.Lengthy drought events are likely to characterize the southern and western parts of Tanzania,while severe flood episodes would feature intensively in the coastal regions and parts of the northeastern highlands of Tanzania.Fewer but heavier rainy days are expected in the 21 st century over Tanzania.3.Contrary to the absence of heatwaves in the EM-DAT database for Tanzania,this study provides scientific evidence of the occurrence of catastrophic heatwaves,which are likely to be intensified and occur more regularly and yearly by mid-century over Tanzania.4.Developed the most comprehensive adaptation mechanism to address the challenges of how to adapt within the SAGCOT region in Tanzania5.Investigated the system rice intensification(SRI)concept in Tanzania and Northeast China as an input for the construction of a climate-resilient technology system over SAGCOT.These findings contribute to updating the scientific understanding of extreme precipitation events in Tanzania and could help develop technical guides in designing adaptation actions,especially for the SAGCOT region.However,this work only focused on a biophysical system,future work could be extended to cover infrastructures which are also at risk in the SAGCOT corridor.