scholarly journals Reproducing complex simulations of economic impacts of climate change with lower-cost emulators

2020 ◽  
Author(s):  
Jun'ya Takakura ◽  
Shinichiro Fujimori ◽  
Kiyoshi Takahashi ◽  
Naota Hanasaki ◽  
Tomoko Hasegawa ◽  
...  

Abstract. In order to project climate-change impacts under a wide-range of scenarios or conduct on-line coupled simulations, the computational and implementation cost of economic impact calculations should be reduced. To do so, in this study, we developed various emulators that mimic simulation outputs, namely economic models coupled with bio/physical process-based impact models. Their performance was evaluated for multiple sectors and regions. Among the tested emulators, those composed of artificial neural networks, which can incorporate nonlinearities and interactions between variables, performed better particularly when finer input variables were available. Although simple functional forms were effective for approximating general tendencies, complex emulators are necessary if the focus is regional or sectoral heterogeneity. The developed emulators could be used to explore future scenarios related to climate-change policies, and the findings of this study could also help researchers design their own emulators under different situations.

2021 ◽  
Vol 14 (5) ◽  
pp. 3121-3140
Author(s):  
Jun'ya Takakura ◽  
Shinichiro Fujimori ◽  
Kiyoshi Takahashi ◽  
Naota Hanasaki ◽  
Tomoko Hasegawa ◽  
...  

Abstract. Process-based models are powerful tools for simulating the economic impacts of climate change, but they are computationally expensive. In order to project climate-change impacts under various scenarios, produce probabilistic ensembles, conduct online coupled simulations, or explore pathways by numerical optimization, the computational and implementation cost of economic impact calculations should be reduced. To do so, in this study, we developed various emulators that mimic the behaviours of simulation models, namely economic models coupled with bio/physical-process-based impact models, by statistical regression techniques. Their performance was evaluated for multiple sectors and regions. Among the tested emulators, those composed of artificial neural networks, which can incorporate non-linearities and interactions between variables, performed better particularly when finer input variables were available. Although simple functional forms were effective for approximating general tendencies, complex emulators are necessary if the focus is regional or sectoral heterogeneity. Since the computational cost of the developed emulators is sufficiently small, they could be used to explore future scenarios related to climate-change policies. The findings of this study could also help researchers design their own emulators in different situations.


2011 ◽  
Vol 02 (02) ◽  
pp. 149-174 ◽  
Author(s):  
PRADEEP KURUKULASURIYA ◽  
NAMRATA KALA ◽  
ROBERT MENDELSOHN

Although there is now an extensive literature on the economic impacts of climate change on agriculture, no study has yet addressed the endogeneity of irrigation. This paper examines how climate affects the choice to irrigate and the conditional income earned by each farmer. The paper develops a selection model of irrigation choice and conditional income. Using data from farmers across eleven African countries, the paper demonstrates that the choice of irrigation is sensitive to both temperature and precipitation. Rainfed and irrigated farm income also both respond to climate but have different climate sensitivity. Impact models that fail to account for endogenous irrigation are biased.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Simon Kapitza ◽  
Pham Van Ha ◽  
Tom Kompas ◽  
Nick Golding ◽  
Natasha C. R. Cadenhead ◽  
...  

AbstractClimate change threatens biodiversity directly by influencing biophysical variables that drive species’ geographic distributions and indirectly through socio-economic changes that influence land use patterns, driven by global consumption, production and climate. To date, no detailed analyses have been produced that assess the relative importance of, or interaction between, these direct and indirect climate change impacts on biodiversity at large scales. Here, we apply a new integrated modelling framework to quantify the relative influence of biophysical and socio-economically mediated impacts on avian species in Vietnam and Australia and we find that socio-economically mediated impacts on suitable ranges are largely outweighed by biophysical impacts. However, by translating economic futures and shocks into spatially explicit predictions of biodiversity change, we now have the power to analyse in a consistent way outcomes for nature and people of any change to policy, regulation, trading conditions or consumption trend at any scale from sub-national to global.


2009 ◽  
Vol 3 (1) ◽  
pp. 123-126 ◽  
Author(s):  
S. M. Attaher ◽  
M. A. Medany ◽  
A. F. Abou-Hadid

Abstract. The overall agricultural system in the Nile Delta region is considered as one of the highest intensive and complicated agriculture systems in the world. According to the recent studies, the Nile Delta region is one of the highly vulnerable regions in the world to climate change. Sea level rise, soil and water degradation, undiversified crop-pattern, yield reduction, pests and disease severity, and irrigation and drainage management were the main key factors that increased vulnerability of the agriculture sector in that region. The main objective of this study is to conduct a community-based multi-criteria adaptation assessment in the Nile Delta using a preset questionnaire. A list of possible adaptation measures for agriculture sector was evaluated. The results indicated that the Nile Delta growers have strong perceptions to act positively to reduce the impacts of climate change. They reflected the need to improve the their adaptive capacity based on clear scientific message with adequate governmental support to coop with the negative impacts of climate change.


2021 ◽  
Author(s):  
Christian Huggel ◽  
Simon K. Allen ◽  
Indra D. Bhatt ◽  
Rithodi Chakraborty ◽  
Fabian Drenkhan ◽  
...  

<p>Mountains cover about a quarter of the Earth’s land surface and are home to or serve a substantial fraction of the global population with essential ecosystem services, in particular water, food, energy, and recreation. While mountain systems are expected to be highly exposed to climate change, we currently lack a comprehensive global picture of the extent to which environmental and human systems in mountain regions have been affected by recent anthropogenic climate change.</p><p>Here we undertake an unprecedented effort to detect observed impacts of climate change in mountains regions across all continents. We follow the approach implemented in the IPCC 5<sup>th</sup> Assessment Report (AR5) and follow-up research where we consider whether a natural or human system has changed beyond its baseline behavior in the absence of climate change, and then attribute the observed change to different drivers, including anthropogenic climate change. We apply an extensive review of peer-reviewed and grey literature and identify more than 300 samples of impacts (aggregate and case studies). We show that a wide range of natural and human systems in mountains have been affected by climate change, including the cryosphere, the water cycle and water resources, terrestrial and aquatic ecosystems, energy production, infrastructure, agriculture, health, migration, tourism, community and cultural values and disasters. Our assessment documents that climate change impacts are observed in mountain regions on all continents. However, the explicit distinction of different drivers contributing to or determining an observed change is often highly challenging; particularly due to widespread data scarcity in mountain regions. In that context, we were also able to document a high amount of impacts in previously under-reported continents such as Africa and South America. In particular, we have been able to include a substantial number of place-based insights from local/indigenous communities representing important alternative worldviews.</p><p>The role of human influence in observed climate changes is evaluated using data from multiple gridded observational climate products and global climate models. We find that anthropogenic climate change has a clear and discernable fingerprint in changing natural and human mountain systems across the globe. In the cryosphere, ecosystems, water resources and tourism the contribution of anthropogenic climate change to observed changes is significant, showing the sensitivity of these systems to current and future climate change. Furthermore, our analysis reveals the need to consider the plurality of knowledge systems through which climate change impacts are being understood in mountain regions. Such attempts at inclusivity, which addresses issues of representation and justice, should be deemed necessary in exploring climate change impacts.</p>


Author(s):  
Iñigo J. Losada ◽  
Paula Camus ◽  
Alexandra Toimil ◽  
Antonio Espejo ◽  
Cristina Izaguirre

Coastal engineers play a leading role in assessing climate change impacts in coastal and low-lying areas and in the design and implementation of adaptation solutions to build resilient coastal systems. Given the continuous growth of coastal communities and assets along the world coastlines, the need to protect and preserve natural and socioeconomic coastal systems and the escalating impacts of climate change (Wong et al. 2014), there is an urgent demand by decision makers for coastal engineering practice dealing with risk assessment and adaptation under high levels of uncertainty.


Author(s):  
U. Rashid Sumaila

This chapter describes the literature of adaptation law in the context of international ocean governance. Adaptation law consists of rules aimed at minimizing the social costs associated with human response to climate impacts. These can be used to shape the behaviour of private actors or public institutions. The law sometimes might provide incentives to make enterprises more resilient as it makes capital unnecessarily stranded during climate change. In order to illustrate the challenges of implementation in the ocean context, the chapter focuses on two examples: international fisheries and ‘mari-engineering’. International fisheries represent ongoing ocean use and regulated by a well-developed body of international law. Due to the wide range of possible climate impacts and adaptive responses, proactive changes to existing fisheries rules in anticipation of climate change fit into the category of general adaptation law, while mari-engineering is engineering the seas to slow or halt climate change impacts.


2019 ◽  
Vol 16 ◽  
pp. 48-61 ◽  
Author(s):  
Pragya Khanal ◽  
Bishnu H. Wagle ◽  
Suraj Upadhaya ◽  
Prayash Ghimire ◽  
Suman Acharya

Climate change is projected to increase in vulnerable areas of the world, and marginalized communities residing in rural areas are more vulnerable to the change. The perceptions of climate change and adaptation strategies made by such communities are important considerations in the design of adaptation strategies by policy-makers. We examined the most marginalized indigenous group "Chepang" communities' perceptions towards this change, variability, and their attitudes to adaptations and adapted coping measures in mid-hills of Nepal. We interviewed 155 individuals from two Chepang communities, namely, Shaktikhor and Siddhi in Chitwan district of Nepal. We also analyzed biophysical data to assess the variability. The findings showed that the Chepang community has experienced significant impacts of climate change and variability. They attributed crop disease, insect infestation, human health problem, and weather-related disaster as the impacts of climate change. Strategies they have adopted in response to the change are the use of intense fertilizers in farmland, hybrid seeds cultivation, crop diversification, etc. Local level and national level adaptation policies need to be designed and implemented as soon as possible to help climate vulnerable communities like Chepangs to cope against the impacts of climate change.


2019 ◽  
Vol 76 (6) ◽  
pp. 1390-1392 ◽  
Author(s):  
Manuel Barange

Abstract It is common to assume that climate change impacts on future fish catches, relative to current levels of catch, are directly proportional to changes in the capacity of the ocean to produce fish. However, this would only be the case if production was optimized, which is not the case, and continues to do so in the future, which we do not know. It is more appropriate to see changes in the ocean’s productive capacity as providing an upper limit to future fish catches, but whether these catches are an increase or a decrease from present catch levels depends on management decisions now and in the future, rather than on the ocean’s productive capacity alone. Disregarding the role of management in driving current and future catches is not only incorrect but it also removes any encouragement for management agencies to improve performance. It is concluded that climate change provides one of the most powerful arguments to improve fisheries—and environmental—management, and thus fisheries sustainability globally.


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