Climate change as a veiled driver of migration in Bangladesh and Ghana.

People living in deltaic areas in developing countries are especially prone to suffer the effects from natural disasters due to their geographical and economic structure. Climate change is contributing to an increase in the frequency and intensity of extreme events affecting the environmental conditions of deltas, threatening the socioeconomic development of people and, eventually, triggering migration as an adaptation strategy. Climate change will likely contribute to worsening environmental stress in deltas, and understanding the relations between climate change, environmental impacts, socioeconomic conditions, and migration is emerging as a key element for planning climate adaptation. In this study, we use data from migration surveys and econometric techniques to analyse the extent to which environmental impacts affect individual migration decision-making in two delta regions in Bangladesh and Ghana. The results show that, in both deltas, climatic shocks that negatively affect economic security are significant drivers of migration, although the surveyed households do not identify environmental pressures as the root cause of the displacement. Furthermore, environmental impacts affecting food security and crop and livestock production are also significant as events inducing people to migrate, but only in Ghana. We also find that suffering from environmental stress can intensify or reduce the effects of socioeconomic drivers. In this sense, adverse climatic shocks may not only have a direct impact on migration but may also condition migration decisions indirectly through the occupation, the education, or the marital status of the person. We conclude that although climate change and related environmental pressures are not perceived as key drivers of migration, they affect migration decisions through indirect channels (e.g., reducing economic security or reinforcing the effect of socioeconomic drivers).

Energy-socio-economic-environmental modelling for the EU energy and post-COVID-19 transitions.

Relevant energy questions have arisen because of the COVID-19 pandemic. The pandemic shock leads to emissions' reductions consistent with the rates of decrease required to achieve the Paris Agreement goals. Those unforeseen drastic reductions in emissions are temporary as long as they do not involve structural changes. However, the COVID-19 consequences and the subsequent policy response will affect the economy for decades. Focusing on the EU, this discussion article argues how recovery plans are an opportunity to deepen the way towards a low-carbon economy, improving at the same time employment, health, and equity and the role of modelling tools. Long-term alignment with the low-carbon path and the development of a resilient transition towards renewable sources should guide instruments and policies, conditioning aid to energy-intensive sectors such as transport, tourism, and the automotive industry. However, the potential dangers of short-termism and carbon leakage persist. The current energy-socio-economic-environmental modelling tools are precious to widen the scope and deal with these complex problems. The scientific community has to assess disparate, non-equilibrium, and non-ordinary scenarios, such as sectors and countries lockdowns, drastic changes in consumption patterns, significant investments in renewable energies, and disruptive technologies and incorporate uncertainty analysis. All these instruments will evaluate the cost-effectiveness of decarbonization options and potential consequences on employment, income distribution, and vulnerability.

The potential land requirements and related land use change emissions of solar energy.

Although the transition to renewable energies will intensify the global competition for land, the potential impacts driven by solar energy remain unexplored. In this work, the potential solar land requirements and related land use change emissions are computed for the EU, India, Japan and South Korea. A novel method is developed within an integrated assessment model which links socioeconomic, energy, land and climate systems. At 25-80% penetration in the electricity mix of those regions by 2050, we find that solar energy may occupy 0.5-5% of total land. The resulting land cover changes, including indirect effects, will likely cause a net release of carbon ranging from 0 to 50 gCO2/kWh, depending on the region, scale of expansion, solar technology efficiency and land management practices in solar parks. Hence, a coordinated planning and regulation of new solar energy infrastructures should be enforced to avoid a significant increase in their life cycle emissions through terrestrial carbon losses.

Effects of climate change and management policies on marine fisheries productivity in the north-east coast of India.

The study covers two important deltaic systems of the north-east coast of India, viz. the Bengal and Mahanadi delta that support about 1.25 million people. The changes in potential marine fish production and socio-economic conditions were modelled for these two deltas under long-term changes in environmental conditions (sea surface temperature and primary production) to the end of the 21st century. Our results show that an increased temperature (by 4 °C) has a negative impact on fisheries productivity, which was projected to decrease by 5%. At the species level, Bombay duck, Indian mackerel and threadfin bream showed an increasing trend in the biomass of potential catches under the sustainable fishing scenario. However, under the business as usual and overfishing scenarios, our results suggest reduced catch for both states. On the other hand, mackerel tuna, Indian oil sardine, and hilsa fisheries showed a projected reduction in potential catch also for the sustainable fishing scenario. The socio-economic models projected an increase of up to 0.67% (involving 0.8 billion USD) in consumption by 2050 even under the best management scenario. The GDP per capita was projected to face a loss of 1.7 billion USD by 2050. The loss of low-cost fisheries would negatively impact the poorer coastal population since they strongly depend upon these fisheries as a source of protein. Nevertheless, adaptation strategies tend to have a negative correlation with poverty and food insecurity which needs to be addressed separately to make the sector-specific efforts effective. This work can be considered as the baseline model for future researchers and the policymakers to explore potential sustainable management options for the studied regions.

Towards a more effective climate policy on international trade.

In the literature on the attribution of responsibilities for greenhouse gas emissions, two accounting methods have been widely discussed: production-based accounting (PBA) and consumption-based accounting (CBA). It has been argued that an accounting framework for attributing responsibilities should credit actions contributing to reduce global emissions and should penalize actions increasing them. Neither PBA nor CBA satisfy this principle. Adapting classical Ricardian trade theory, we consider ex post measurement and propose a scheme for assigning credits and penalties. Their size is determined by how much CO2 emissions are saved globally due to trade. This leads to the emission responsibility allotment (ERA) for assigning responsibilities. We illustrate the differences between ERA and PBA and CBA by comparing their results for 41 countries and regions between 1995-2009. The Paris Agreement (COP21) proposed new market mechanisms; we argue that ERA is well suited to measure and evaluate their overall mitigation impact.

The socioeconomic future of deltas in a changing environment.

Deltas are especially vulnerable to climate change given their low-lying location and exposure to storm surges, coastal and fluvial flooding, sea level rise and subsidence. Increases in such events and other circumstances are contributing to the change in the environmental conditions in the deltas, which translates into changes in the productivity of ecosystems and, ultimately, into impacts on livelihoods and human well-being. Accordingly, climate change will affect not only the biophysical conditions of deltaic environments but also their economic circumstances. Furthermore, these economic implications will spill over to other regions through goods and services supply chains and via migration. In this paper we take a wider view about some of the specific studies within this Special Issue. We analyse the extent to which the biophysical context of the deltas contributes to the sustainability of the different economic activities, in the deltas and in other regions. We construct a set of environmental-extended multiregional input-output databases and Social Accounting Matrices that are used to trace the flow of provisioning ecosystem services across the supply chains, providing a view of the links between the biophysical environment and the economic activities. We also integrate this information into a Computable General Equilibrium model to assess how the changes in the provision of natural resources due to climate change can potentially affect the economies of the deltas and linked regions, and how this in turn affects economic vulnerability and sustainability in these regions.

Is Seasonal Households' Consumption Good for the Nexus Carbon/Water Footprint? The Spanish Fruits and Vegetables Case.

Proximity and in-season consumption criteria have been suggested as solutions for fruits and vegetables consumers to drive the economy to a more sustainable development. Using a new concept, seasonal avoided footprint by imports, we disentangle the role of period and country of origin. Although, as a general rule, consumers could reduce the footprint by choosing domestic produce, this is not always the case. Due to the high efficiency of Spanish domestic production in terms of both CO2e and water use (except for scarce water), imports from some regions, like Africa (green beans, peppers, tomatoes, bananas, strawberries, oranges), contribute to significantly increasing both water and carbon impacts. However, a monthly basis analysis shows unsustainable hotspots for domestic production. Importing from France (apples, potatoes) or Portugal (tomatoes, strawberries) reduces both footprints, so Spanish local consumption would be bad for the environment. Hotspots are mainly concentrated in scarce water and, especially, for out-of-season vegetables during 11 months a year (savings up to 389%), nine months for out-of-season fruits, and five months for in-season fruits. The results suggest the difficulty to generalize an easy environmental recommendation based on buying local fruits and vegetables: consumption must be analyzed on monthly/seasonal, product, and country bases.

Importance of fisheries for food security across three climate change vulnerable deltas.

Deltas are home to a large and growing proportion of the world's population, often living in conditions of extreme poverty. Deltaic ecosystems are ecologically significant as they support high biodiversity and a variety of fisheries, however these coastal environments are extremely vulnerable to climate change. The Ganges-Brahmaputra-Meghna (Bangladesh/India), the Mahanadi (India), and the Volta (Ghana) are among the most important and populous delta regions in the world and they are all considered at risk of food insecurity and climate change. The fisheries sector is vital for populations that live in the three deltas, as a source of animal protein (in Bangladesh and Ghana around 50-60% of animal protein is supplied by fish while in India this is about 12%) through subsistence fishing, as a source of employment and for the wider economy. The aquaculture sector shows a rapid growth in Bangladesh and India while in Ghana this is just starting to expand. The main exported species differ across countries with Ghana and India dominated by marine fish species, whereas Bangladesh exports shrimps and prawns. Fisheries play a more important part in the economy of Bangladesh and Ghana than for India, both men and women work in fisheries, with a higher proportion of women in the Volta then in the Asian deltas. Economic and integrated modelling using future scenarios suggest that changes in temperature and primary production could reduce fish productivity and fisheries income especially in the Volta and Bangladesh deltas, however these losses could be mitigated by reducing overfishing and improving management. The analysis provided in this paper highlights the importance of applying plans for fisheries management at regional level. Minimizing the impacts of climate change while increasing marine ecosystems resilience must be a priority for scientists and governments before these have dramatic impacts on millions of people's lives.

Applying the global RCP-SSP-SPA scenario framework at sub-national scale: A multi-scale and participatory scenario approach.

To better anticipate potential impacts of climate change, diverse information about the future is required, including climate, society and economy, and adaptation and mitigation. To address this need, a global RCP (Representative Concentration Pathways), SSP (Shared Socio-economic Pathways), and SPA (Shared climate Policy Assumptions) (RCP-SSP-SPA) scenario framework has been developed by the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC-AR5). Application of this full global framework at sub-national scales introduces two key challenges: added complexity in capturing the multiple dimensions of change, and issues of scale. Perhaps for this reason, there are few such applications of this new framework. Here, we present an integrated multi-scale hybrid scenario approach that combines both expert-based and participatory methods. The framework has been developed and applied within the DECCMA1 project with the purpose of exploring migration and adaptation in three deltas across West Africa and South Asia: (i) the Volta delta (Ghana), (ii) the Mahanadi delta (India), and (iii) the Ganges-Brahmaputra-Meghna (GBM) delta (Bangladesh/India). Using a climate scenario that encompasses a wide range of impacts (RCP8.5) combined with three SSP-based socio-economic scenarios (SSP2, SSP3, SSP5), we generate highly divergent and challenging scenario contexts across multiple scales against which robustness of the human and natural systems within the deltas are tested. In addition, we consider four distinct adaptation policy trajectories: Minimum intervention, Economic capacity expansion, System efficiency enhancement, and System restructuring, which describe alternative future bundles of adaptation actions/measures under different socio-economic trajectories. The paper highlights the importance of multi-scale (combined top-down and bottom-up) and participatory (joint expert-stakeholder) scenario methods for addressing uncertainty in adaptation decision-making. The framework facilitates improved integrated assessments of the potential impacts and plausible adaptation policy choices (including migration) under uncertain future changing conditions. The concept, methods, and processes presented are transferable to other sub-national socio-ecological settings with multi-scale challenges.

Multiregional input-output model for the evaluation of Spanish water flows.

We construct a multiregional input-output model for Spain, in order to evaluate the pressures on the water resources, virtual water flows, and water footprints of the regions, and the water impact of trade relationships within Spain and abroad. The study is framed with those interregional input-output models constructed to study water flows and impacts of regions in China, Australia, Mexico, or the UK. To build our database, we reconcile regional IO tables, national and regional accountancy of Spain, trade and water data. Results show an important imbalance between origin of water resources and final destination, with significant water pressures in the South, Mediterranean, and some central regions. The most populated and dynamic regions of Madrid and Barcelona are important drivers of water consumption in Spain. Main virtual water exporters are the South and Central agrarian regions: Andalusia, Castile-La Mancha, Castile-Leon, Aragon, and Extremadura, while the main virtual water importers are the industrialized regions of Madrid, Basque country, and the Mediterranean coast. The paper shows the different location of direct and indirect consumers of water in Spain and how the economic trade and consumption pattern of certain areas has significant impacts on the availability of water resources in other different and often drier regions.

Water flows in the Spanish economy: agri-food sectors, trade and households diets in an input-output framework.

Seeking to advance our knowledge of water flows and footprints and the factors underlying them, we apply, on the basis of an extended 2004 Social Accounting Matrix for Spain, an open Leontief model in which households and foreign trade are the exogenous accounts. The model shows the water embodied in products bought by consumers (which we identify with the Water Footprint) and in trade (identified with virtual water trade). Activities with relevant water inflows and outflows such as the agrarian sector, textiles, and the agri-food industry are examined in detail using breakdowns of the relevant accounts. The data reflect only physical consumption, differentiating between green and blue water. The results reveal that Spain is a net importer of water. Flows are then related to key trading partners to show the large quantities involved. The focus on embodied (or virtual) water by activity is helpful to distinguish indirect from direct consumption as embodied water can be more than 300 times direct consumption in some food industry activities. Finally, a sensitivity analysis applied to changes in diets shows the possibility of reducing water uses by modifying households' behavior to encourage healthier eating.