This paper presents the results of the “Economic Evaluation of Climatic Change Impacts on Water Resources at River Basin Scale” project (eec2-water project) developed in Chile, Colombia, and Bolivia. The project is a combined effort between Universities, NGOs, and local government institutions, which aims at providing useful information for policy makers, increase awareness about climate change among stakeholders and fostering undergraduate and graduate students.
The main objective of this project is to provide an analytical tool that allows policy makers to identify the economic impacts of climate change on water availability at a basin scale taking into consideration the spatial allocation of users and to evaluate different policy strategies in order to minimize the economic impact of those changes.
To reach our goal we rely on a hydro-economic model, which links the physical impacts of climate change (decrease on water availability) with the economic responses of water users. The physical impacts on water supply are modeled using the SWAT hydrologic model for the basin, and the potential economic responses of distinct water users are analyzed using an appropriate combination of econometric and optimization methods.
This approach allows us to identify both the economic sectors and the population groups that will likely be affected by changes on water availability, as well as to identify policy alternatives that can be used to cope with climate change, and evaluate them using a cost effectiveness approach. Any potential change would have winners and losers, but some of the affected communities are not necessarily identified by the hydro-economic model due to their little share in the agricultural production or residential consumption. This is, for instance, the case of several agricultural communities oriented to subsistence agricultural production. Therefore, our hydro-economic analysis is accompanied by the identification of the most vulnerable communities using participatory techniques.
Often technical information is hardly apprehended by decision makers and therefore not incorporated in the planning process. On the other hand, many types of data are constantly produced and still poorly interpreted. Additionally, when the topic is climate change, the difficulty in understanding its complexity and at the same time find the balance among science and policy implementation can be even more challenging.
With that in mind, the project aims to quantify economic loss in monetary terms as a consequence of variations in flow rates patters due to possible effects of climate change, and therefore water availability, over a river basin located in northeast Brazil, region well recognized for its drought problems and social vulnerability.
For this propose, different future climate and economic scenarios were simulated through specific water allocation decision support system that computes how this resource will be distributed according to the set priorities. In the local context, human and animal supplies are always the first priority, followed by agriculture, industry and aquaculture, in this order. As an outcome, the modeling provides corresponding water deficits in a monthly basis based on each user.
It is recognized that users will respond differently to a scarcity situation, therefore each type of activity needs to be addressed from a specific angle. To estimate the loss in monetary terms several economic methods can be appropriate depending on the desired level of coverage. In this sense, the economic loss was calculated considering how a potential deficit can affect the production of goods for each user.
By translating water scarcity into economic value it is possible to bring together climate change understanding and management in a hydrologic perspective and thus provide objectivity to decision makers. Through a more practical point of view, also offer solid ground for further planning pertinent applications, like cost-benefit, cost-effectiveness and multicriteria analyses, among others.
Significant value is at stake. The results shows that, when compared to the baseline scenario, the total deficit in the river basin can be up to 133% higher in the worst case scenario, corresponding to a potential total economic loss estimated around US$ 1.16 trillion until 2065.
Consequently, it is possible through an economic standpoint to measure the dimension of the potential loss and begin to understand how water shortage can affect societal and productivity dynamics. By translating something as abstract as climate change into physical risk and ultimately into a tangible financial damage, the decision making process can be guided in a robust manner, offering palpable scientific substance to the policy sphere. Moreover, the economic loss was estimated for six different future configurations of climate and economics dynamics, scaling up scenario planning and promoting strong adaptation actions strategies.
Besides that, the distance between scientific approach and management actions start to be reduced. Advances in economic loss estimation methodology can solidify its understating and replicability, empowering decision makers and consequently promoting general welfare.
The aim of the project was to define future climate scenarios considering possible changes in patterns and physical behaviors of a river basin located in Northeast Brazil. Although the intention seems common, its methodology has potential to represent a new understanding over scenario planning under the context of a changing climate. Once introducing a counterpoint to GCMs (General Circulation Models) when engaged in a practical application, the goal is to embrace uncertainty and promote its incorporation on climate risk management.
Far from the ambition of predicting the future, the challenge is to find an efficient set of scenarios that can represent possible and plausible situations and therefore perceive science in a more comprehensive way, placing the habitual predictive modeling closer to the decision-making process.
The region of interest is recognized as one of the most vulnerable in the country, being constantly threatened by rough droughts. Besides that, the area itself already has to deal with its peculiar climate dynamics: all the rain drops between February and May in a way that the water supplies for the rest of the year depends primarily on this period. Therefore, the basin is mainly characterized as a system of 51 integrated reservoirs operating in order to maintain the water flow and storage.
Being of high national interest, the region is the focus of different researches. A previous study compiled IPCC’s 21 GCMs results of precipitation, evaporation and flow data. Such results were than analyzed using statistics methods to understand the main hydroclimate parameters to be replicated in order to achieve a contextualized and representative ensemble of future flow rates scenarios.
In a simplified way the methodology establishes, in this order, the following steps:
Three scenarios came out from the process, each one representing a different possible future state, gathering a range of interesting contexts and comprehending many potential analyses. In a changing climate, relying upon just one GCM might be inefficient in the public policy sphere. Thus, to embrace uncertainty means not trying to have a better prediction of the future, but to be better prepared for whatever the future might be.
The process involving data acquisition, processing and application of GCMs is still unclear and inaccessible to most decision-makers. Trying another approach and use in a consistent way the results of GCMs can open a whole new perspective for this field in the public policy dimension.
The stromatolites are organosedimentary carbonate deposits formed from the interaction between benthic microbial communities and detrital sediments. These structures are unique in the Bacalar lagoon because they are one of the largest freshwater microbialite occurrences in the world. The Bacalar lagoon is facing to antrophogenic activities increasing like wastewater non treated, use of pesticides, etc. The Bacalar town becomes a municipality 3 years ago, and the plans for urban development, and tourism (infrastructure and activities) investments are causing a pressure over these ancient structures and over the symbolic lagoon (called “Seven colors Lagoon”). Besides, the tourist activities in the lake also disturb the water characteristics.
The carbonate structures(stromatolites) are present worldwide and in the Bacalar lagoon are particularly important, because they preserve past information about the climatic and life conditions in the moment of their sedimentation. The analysis of sedimentary record of these structures permit to realize a paleohydrology reconstruction indicated how the Bacalar lagoon have changed through the time, in terms of the chemical composition, changes in temperature and precipitation (climate change), and due to the groundwater contribution and other factors.
Through this investigation it could be seen the changes in the composition and dynamic of the lagoon, and the results can let us to make some projections (climatic, recharge and anthropogenic).
For the study, six cores of the stromatolites were collected in the west part of the lagoon. Also, sediment and water samples were collected in order to assess the quality in the influence area of the collected cores. To establish the chronology of the lacustrine sequence, the cores were dated through AMS 14C at the University of California Santa Cruz. Furthermore, the stable isotopes as 18O and 13C were analyzed. Additionally, it was determined the concentration of trace elements and the rare earth elements (REE). To water characterization, the pH, temperature, dissolved oxygen, conductivity, alkalinity, nutrients, major and trace elements concentration were determined in the collected samples. With the analysis we can infer the factors of regulation and behavior patters.
The Bacalar lagoon does not have a regulation like protected area, and the management plan is been developed. The tourism and economic activities are impacting the ecosystem. The Bacalar Lagoon ecosystems need a protection, governance and policies in adaptation/resilience programs facing to climate change. To define policies based on scientific research, using ancient structures like stromatolites as proxies, to explain the past and to help us to answer the present challenges, and to visualize the future transformations, it is fundamental in order to make decisions and take action about the management of the coastal lagoon in the Mexican Caribbean.
Climate change is likely to impact the Australian continent by changing the trends of rainfall, increasing temperature and affecting the accessibility of water quantity and quality. The problem of future water resources availability in Australia has drawn the attention of many researchers to investigate this matter for planning and control purposes. This study presents the future climate change impact on streamflow variability in the contributing catchment of the Goulburn River at Coggan, Hydrologic Reference Stations (HRS) in New South Wales, Australia. Goulburn River catchment distributed over 3402 km2 area and it forms the whole western part of the Hunter River catchment which is the largest coastal catchment in NSW. The Australian HRS network represent ‘living gauges’ that enable the long-term investigation of water resources availability in the contributing catchments. The impact of future climate changes on the corresponding catchments of the HRS is then of great interest, for planning and management purposes, to investigate how climate change will impact the availability of future water resources in these regions.
The HBV conceptual model is applied to simulate the discharge at Coggan HRS for two future periods, mid (2046-2065) and late (2080-2099) of the current century.Daily observed rainfall, temperature, discharge and monthly mean potential evapotranspiration from the contributing catchment of Coggan HRS are used to run, calibrate and validate the HBV model prior to the simulation process. The modelling performance was assessed using three efficiency criteria including Nash-Sutcliffe efficiency (NSE.), relative volume error (VE) and the coefficient of determination (r2). The calibration and validation results revealed a good modelling performance which indicates that the model could be used successfully to simulate the future discharge at Coggan HRS. The downscaled and bias corrected future rainfall and temperature from a multi-model ensemble of eight Global Climate Models (GCMs) from the CMIP5 model under two Representative Concentration Pathways, RCP 4.5 and RCP 8.5 are used to force the HBV model to simulate the future streamflow at Coggan HRS. The CSIRO and the Australian Bureau of Meteorology explained that the GCMs used in the present study represent the best eight GCMs out of 40 GCMs of the CMIP5 that can be used effectively to investigate the Australian future climatic conditions especially for the impact assessment studies.Results show a clear rainfall-runoff reduction trend across the contributing catchment of Coggan HRS for the mid (2046-2065) and late (2080-2099) of the 21st century under the two climate scenarios as compared to the control run. The results are also in well-match with the streamflow reduction trend provided by the Australian Bruere of Meteorology through the step change analysis of the historical observed mean annual streamflow. The findings of this study will be helpful for local communities and decision makers to manage the usage of future water resources in the contributing catchment such as irrigation, domestic and even drinking by taking into consideration the low flows situation.