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- ItemThe impact of climate conditions on economic production. Evidence from a global panel of regions(Amsterdam [u.a.] : Elsevier, 2020) Kalkuhl, Matthias; Wenz, LeonieWe present a novel data set of subnational economic output, Gross Regional Product (GRP), for more than 1500 regions in 77 countries that allows us to empirically estimate historic climate impacts at different time scales. Employing annual panel models, long-difference regressions and cross-sectional regressions, we identify effects on productivity levels and productivity growth. We do not find evidence for permanent growth rate impacts but we find robust evidence that temperature affects productivity levels considerably. An increase in global mean surface temperature by about 3.5°C until the end of the century would reduce global output by 7–14% in 2100, with even higher damages in tropical and poor regions. Updating the DICE damage function with our estimates suggests that the social cost of carbon from temperature-induced productivity losses is on the order of 73–142$/tCO2 in 2020, rising to 92–181$/tCO2 in 2030. These numbers exclude non-market damages and damages from extreme weather events or sea-level rise. © 2020 The Authors
- ItemHydro-Economic Modelling for Water-Policy Assessment Under Climate Change at a River Basin Scale: A Review(Basel : MDPI, 2020) Expósito, Alfonso; Beier, Felicitas; Berbel, JulioHydro-economic models (HEMs) constitute useful instruments to assess water-resource management and inform water policy. In the last decade, HEMs have achieved significant advances regarding the assessment of the impacts of water-policy instruments at a river basin or catchment level in the context of climate change (CC). This paper offers an overview of the alternative approaches used in river-basin hydro-economic modelling to address water-resource management issues and CC during the past decade. Additionally, it analyses how uncertainty and risk factors of global CC have been treated in recent HEMs, offering a discussion on these last advances. As the main conclusion, current challenges in the realm of hydro-economic modelling include the representation of the food-energy-water nexus, the successful representation of micro-macro linkages and feedback loops between the socio-economic model components and the physical side, and the treatment of CC uncertainties and risks in the analysis.
- ItemA review of the potential climate change impacts and adaptation options for European viticulture(Basel : MDPI, 2020) Santos, João A.; Fraga, Helder; Malheiro, Aureliano C.; Moutinho-Pereira, José; Dinis, Lia-Tânia; Correia, Carlos; Moriondo, Marco; Leolini, Luisa; Dibari, Camilla; Costafreda-Aumedes, Sergi; Kartschall, Thomas; Menz, Christoph; Molitor, Daniel; Junk, Jürgen; Beyer, Marco; Schultz, Hans R.Viticulture and winemaking are important socioeconomic sectors in many European regions. Climate plays a vital role in the terroir of a given wine region, as it strongly controls canopy microclimate, vine growth, vine physiology, yield, and berry composition, which together determine wine attributes and typicity. New challenges are, however, predicted to arise from climate change, as grapevine cultivation is deeply dependent on weather and climate conditions. Changes in viticultural suitability over the last decades, for viticulture in general or the use of specific varieties, have already been reported for many wine regions. Despite spatially heterogeneous impacts, climate change is anticipated to exacerbate these recent trends on suitability for wine production. These shifts may reshape the geographical distribution of wine regions, while wine typicity may also be threatened in most cases. Changing climates will thereby urge for the implementation of timely, suitable, and cost-effective adaptation strategies, which should also be thoroughly planned and tuned to local conditions for an effective risk reduction. Although the potential of the different adaptation options is not yet fully investigated, deserving further research activities, their adoption will be of utmost relevance to maintain the socioeconomic and environmental sustainability of the highly valued viticulture and winemaking sector in Europe. © 2020 by the authors.
- ItemCan Tanzania’s adaptation measures prevent future maize yield decline? A simulation study from Singida region(Berlin ; Heidelberg ; New York : Springer, 2021) Volk, Johanna; Gornott, Christoph; Sieber, Stefan; Lana, Marcos AlbertoCereal crop production in sub-Saharan Africa has not achieved the much-needed increase in yields to foster economic development and food security. Maize yields in the region’s semi-arid agroecosystems are constrained by highly variable rainfall, which may be worsened by climate change. Thus, the Tanzanian government has prioritized agriculture as an adaptation sector in its intended nationally determined contribution, and crop management adjustments as a key investment area in its Agricultural Sector Development Programme. In this study, we investigated how future changes in maize yields under different climate scenarios can be countered by regional adjusted crop management and cultivar adaptation strategies. A crop model was used to simulate maize yields in the Singida region of Tanzania for the baseline period 1980–2012 and under three future climate projections for 2020–2060 and 2061–2099. Adaptation strategies to improve yields were full irrigation, deficit irrigation, mulch and nitrogen addition and another cultivar. According to our model results, increase in temperature is the main driver of future maize yield decline. Increased respiration and phenological development were associated with lower maize yields of 16% in 2020–2060 and 20% in 2061–2099 compared to the 1980–2012 baseline. Surprisingly, none of the management strategies significantly improved yields; however, a different maize variety that was tested as an alternative coping strategy performed better. This study suggests that investment in accessibility of improved varieties and investigation of maize traits that have the potential to perform well in a warmer future are better suited for sustaining maize production in the semi-arid region than adjustments in crop management.
- ItemHow evaluation of global hydrological models can help to improve credibility of river discharge projections under climate change(Dordrecht [u.a.] : Springer Science + Business Media B.V, 2020) Krysanova, Valentina; Zaherpour, Jamal; Didovets, Iulii; Gosling, Simon N.; Gerten, Dieter; Hanasaki, Naota; Müller Schmied, Hannes; Pokhrel, Yadu; Satoh, Yusuke; Tang, Qiuhong; Wada, YoshihideImportance of evaluation of global hydrological models (gHMs) before doing climate impact assessment was underlined in several studies. The main objective of this study is to evaluate the performance of six gHMs in simulating observed discharge for a set of 57 large catchments applying common metrics with thresholds for the monthly and seasonal dynamics and summarize them estimating an aggregated index of model performance for each model in each basin. One model showed a good performance, and other five showed a weak or poor performance in most of the basins. In 15 catchments, evaluation results of all models were poor. The model evaluation was supplemented by climate impact assessment for a subset of 12 representative catchments using (1) usual ensemble mean approach and (2) weighted mean approach based on model performance, and the outcomes were compared. The comparison of impacts in terms of mean monthly and mean annual discharges using two approaches has shown that in four basins, differences were negligible or small, and in eight catchments, differences in mean monthly, mean annual discharge or both were moderate to large. The spreads were notably decreased in most cases when the second method was applied. It can be concluded that for improving credibility of projections, the model evaluation and application of the weighted mean approach could be recommended, especially if the mean monthly (seasonal) impacts are of interest, whereas the ensemble mean approach could be applied for projecting the mean annual changes. The calibration of gHMs could improve their performance and, consequently, the credibility of projections. © 2020, The Author(s).
- ItemAtmospheric CO2 availability induces varying responses in net photosynthesis, toxin production and N2 fixation rates in heterocystous filamentous Cyanobacteria (Nostoc and Nodularia)(Basel ; Heidelberg : Springer, 2021) Wannicke, Nicola; Herrmann, Achim; Gehringer, Michelle M.Heterocystous Cyanobacteria of the genus Nodularia form major blooms in brackish waters, while terrestrial Nostoc species occur worldwide, often associated in biological soil crusts. Both genera, by virtue of their ability to fix N2 and conduct oxygenic photosynthesis, contribute significantly to global primary productivity. Select Nostoc and Nodularia species produce the hepatotoxin nodularin and whether its production will change under climate change conditions needs to be assessed. In light of this, the effects of elevated atmospheric CO2 availability on growth, carbon and N2 fixation as well as nodularin production were investigated in toxin and non-toxin producing species of both genera. Results highlighted the following:Biomass and volume specific biological nitrogen fixation (BNF) rates were respectively almost six and 17 fold higher in the aquatic Nodularia species compared to the terrestrial Nostoc species tested, under elevated CO2 conditions.There was a direct correlation between elevated CO2 and decreased dry weight specific cellular nodularin content in a diazotrophically grown terrestrial Nostoc species, and the aquatic Nodularia species, regardless of nitrogen availability.Elevated atmospheric CO2 levels were correlated to a reduction in biomass specific BNF rates in non-toxic Nodularia species.Nodularin producers exhibited stronger stimulation of net photosynthesis rates (NP) and growth (more positive Cohen’s d) and less stimulation of dark respiration and BNF per volume compared to non-nodularin producers under elevated CO2 levels. This study is the first to provide information on NP and nodularin production under elevated atmospheric CO2 levels for Nodularia and Nostoc species under nitrogen replete and diazotrophic conditions.
- ItemFrom Paris to Makkah: heat stress risks for Muslim pilgrims at 1.5 °C and 2 °C(Bristol : IOP Publ., 2021-2-9) Saeed, Fahad; Schleussner, Carl-Friedrich; Almazroui, MansourThe pilgrimages of Muslims to Makkah (Hajj and Umrah) is one of the largest religious gatherings in the world which draws millions of people from around 180 countries each year. Heat stress during summer has led to health impacts including morbidity and mortality in the past, which is likely to worsen due to global warming. Here we investigate the impacts of increasing heat stress during the peak summer months over Makkah at present levels of warming as well as under Paris Agreement's targets of 1.5 °C and 2 °C global mean temperature increase above pre-industrial levels. This is achieved by using multi member ensemble projections from the half a degree additional warming, prognosis and projected impacts project. We find a substantial increase in the exceedance probabilities of dangerous thresholds (wet-bulb temperature >24.6 °C) in 1.5 °C and 2 °C warmer worlds over the summer months. For the 3 hottest months, August, September and October, even thresholds of extremely dangerous (wet-bulb temperature >29.1 °C) health risks may be surpassed. An increase in exceedance probability of dangerous threshold is projected by two and three times in 1.5 °C and 2 °C warmer worlds respectively for May as compared to the reference climate. September shows the highest increase in the exceedance probability of extremely dangerous threshold which is increased to 4 and 13 times in 1.5 °C and 2 °C warmer worlds respectively. Based on the indicators of hazard, exposure and vulnerability, we carried out probabilistic risk analysis of life-threatening heat stroke over Makkah. A ten time increase in the heat stroke risk at higher wet-bulb temperatures for each month is projected in 2 °C warmer world. If warming was limited to 1.5 °C world, the risk would only increase by about five times, or half the risk of 2 °C. Our results indicate that substantial heat related risks during Hajj and Umrah happening over peak summer months, as it is the case for Hajj during this decade, will require substantial adaptation measures and would negatively affect the performance of the rite. Stringent mitigation actions to keep the global temperature to 1.5 °C can reduce the risks of heat related illnesses and thereby reduce the non-economic loss and damage related to one of the central pillars of a world religion.
- ItemPotential impacts of climate change on agriculture and fisheries production in 72 tropical coastal communities(London : Nature Publishing Group, 2022) Cinner, Joshua E; Caldwell, Iain R; Thiault, Lauric; Ben, John; Blanchard, Julia L; Coll, Marta; Diedrich, Amy; Eddy, Tyler D; Everett, Jason D; Folberth, Christian; Gascuel, Didier; Guiet, Jerome; Gurney, Georgina G; Heneghan, Ryan F; Jägermeyr, Jonas; Jiddawi, Narriman; Lahari, Rachael; Kuange, John; Liu, Wenfeng; Maury, Olivier; Müller, Christoph; Novaglio, Camilla; Palacios-Abrantes, Juliano; Petrik, Colleen M; Rabearisoa, Ando; Tittensor, Derek P; Wamukota, Andrew; Pollnac, RichardClimate change is expected to profoundly affect key food production sectors, including fisheries and agriculture. However, the potential impacts of climate change on these sectors are rarely considered jointly, especially below national scales, which can mask substantial variability in how communities will be affected. Here, we combine socioeconomic surveys of 3,008 households and intersectoral multi-model simulation outputs to conduct a sub-national analysis of the potential impacts of climate change on fisheries and agriculture in 72 coastal communities across five Indo-Pacific countries (Indonesia, Madagascar, Papua New Guinea, Philippines, and Tanzania). Our study reveals three key findings: First, overall potential losses to fisheries are higher than potential losses to agriculture. Second, while most locations (> 2/3) will experience potential losses to both fisheries and agriculture simultaneously, climate change mitigation could reduce the proportion of places facing that double burden. Third, potential impacts are more likely in communities with lower socioeconomic status.
- ItemIncreasing compound warm spells and droughts in the Mediterranean Basin(Amsterdam [u.a.] : Elsevier, 2021) Vogel, Johannes; Paton, Eva; Aich, Valentin; Bronstert, AxelThe co-occurrence of warm spells and droughts can lead to detrimental socio-economic and ecological impacts, largely surpassing the impacts of either warm spells or droughts alone. We quantify changes in the number of compound warm spells and droughts from 1979 to 2018 in the Mediterranean Basin using the ERA5 data set. We analyse two types of compound events: 1) warm season compound events, which are extreme in absolute terms in the warm season from May to October and 2) year-round deseasonalised compound events, which are extreme in relative terms respective to the time of the year. The number of compound events increases significantly and especially warm spells are increasing strongly – with an annual growth rates of 3.9 (3.5) % for warm season (deseasonalised) compound events and 4.6 (4.4) % for warm spells –, whereas for droughts the change is more ambiguous depending on the applied definition. Therefore, the rise in the number of compound events is primarily driven by temperature changes and not the lack of precipitation. The months July and August show the highest increases in warm season compound events, whereas the highest increases of deseasonalised compound events occur in spring and early summer. This increase in deseasonalised compound events can potentially have a significant impact on the functioning of Mediterranean ecosystems as this is the peak phase of ecosystem productivity and a vital phenophase.
- ItemThe strategic dimension of financing global public goods(Amsterdam : Elsevier, 2020) Kornek, Ulrike; Edenhofer, OttmarOne challenge in addressing transboundary problems such as climate change is the incentive to free-ride. Transfers from multilateral compensation funds are often used to counteract such incentives, albeit with varying success. We examine how such funds can change the incentive to free-ride in a global public-goods game. In our game, self-interested countries choose their own preferred course, deciding their voluntary public good provision, whether to join a fund that offers compensation for providing the public good and the volume of compensatory payments. We show that (i) total public-good provision is higher when those contributing are given more compensation; and (ii) non-participation in the fund can be punished if the remaining members decrease their public-good provision sufficiently. We then examine three specific fund designs. In the first, the compensation paid to each country is equal to the percentage of above-average total costs for public-goods provision. This design is best able to deter free-riding and can establish the social optimum as the equilibrium. In the second, the compensation paid to each country is a function of the marginal cost of their public-good provision. Here there are significant incentives to free-ride. In the third case, the monetary resources provided by the fund are fixed, a design frequently encountered in international funds. This design is the one least able to deter free-riding. © 2020 The Author(s)