Browsing by Author "Meza, Francisco"
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- ItemAnalysis of Climate-Related Risks for Chile's Coastal Settlements in the ARClim Web Platform(2022) Winckler, Patricio; Contreras-Lopez, Manuel; Garreaud, Rene; Meza, Francisco; Larraguibel, Cristian; Esparza, Cesar; Gelcich, Stefan; Falvey, Mark; Mora, JavieraThe web-based tool ARClim provides an atlas of climate change-related risk assessments spanning over 50 environmental and productive sectors in Chile. This paper illustrates the implementation of ARClim on two coastal sectors, operational downtime in fishing coves and flooding in coastal settlements, aiming to provide a tool to visualize comparative estimates of risk, which may enable decision makers and stakeholders to prioritize adaptation measures. The risk is calculated as a function of the hazard, exposure, and sensitivity. Exposure and sensitivity are characterized using present day information. To assess the hazard, wave climate for a historical period (1985-2004) and a projection (2026-2045) were modeled with six general circulation models (GCMs) for an RCP8.5 scenario. Similarly, sea-level rise was computed from 21 GCMs. Results show that the flooding hazard is mostly dependent on sea-level rise, with waves playing a minor role. However, the flooding risk is highly variable along the coast, due to differences in the exposure, which strongly depends on the population of each settlement. The analysis of increased operational downtime in fishing coves also shows risk, which is dependent of the size of each site. Lastly, limitations of the analysis and opportunities for improvement are discussed.
- ItemAssessing temperature-based adaptation limits to climate change of temperate perennial fruit crops(2023) Meza, Francisco; Darbyshire, Rebecca; Farrell, Aidan; Lakso, Alan; Lawson, James; Meinke, Holger; Nelson, Gerald; Stockle, ClaudioTemperate perennial fruit and nut trees play varying roles in world food diversity-providing edible oils and micronutrient, energy, and protein dense foods. In addition, perennials reuse significant amounts of biomass each year providing a unique resilience. But they also have a unique sensitivity to seasonal temperatures, requiring a period of dormancy for successful growing season production. This paper takes a global view of five temperate tree fruit crops-apples, cherries, almonds, olives, and grapes-and assesses the effects of future temperature changes on thermal suitability. It uses climate data from five earth system models for two CMIP6 climate scenarios and temperature-related indices of stress to indicate potential future areas where crops cannot be grown and highlight potential new suitable regions. The loss of currently suitable areas and new additions in new locations varies by scenario. In the southern hemisphere (SH), end-century (2081-2100) suitable areas under the SSP 5-8.5 scenario decline by more than 40% compared to a recent historical period (1991-2010). In the northern hemisphere (NH) suitability increases by 20% to almost 60%. With SSP1-2.6, however, the changes are much smaller with SH area declining by about 25% and NH increasing by about 10%. The results suggest substantial restructuring of global production for these crops. Essentially, climate change shifts temperature-suitable locations toward higher latitudes. In the SH, most of the historically suitable areas were already at the southern end of the landmass limiting opportunities for adaptation. If breeding efforts can bring chilling requirements for the major cultivars closer to that currently seen in some cultivars, suitable areas at the end of the century are greater, but higher summer temperatures offset the extent. The high value of fruit crops provides adaptation opportunities such as cultivar selection, canopy cooling using sprinklers, shade netting, and precision irrigation.
- ItemDo ecosystem insecurity and social vulnerability lead to failure of water security?(2021) Scott, Christopher A.; Zilio, Mariana I.; Harmon, Thomas; Zuniga-Teran, Adriana; Diaz-Caravantes, Rolando; Hoyos, Natalia; Perillo, Gerardo M. E.; Meza, Francisco; Varady, Robert G.; Neto, Alfredo Ribeiro; Velez, Maria Isabel; Martin, Facundo; Escobar, Jaime; Piccolo, M. Cintia; Mussetta, Paula; Montenegro, Suzana; Rusak, James A.; Pineda, NicolasAchieving water security for humans and ecosystems is a pervasive challenge globally. Extensive areas of the Americas are at significant risk of water insecurity, resulting from global-change processes coupled with regional and local impacts. Drought, flooding, and water quality challenges pose significant threats, while at the same time, rapid urban expansion, competing water demands, river modifications, and expanding global markets for water-intensive agricultural products drive water insecurity. This paper takes a social-ecological systems perspective, aiming to identify examples and pathways towards resilient ecosystems and social development. It draws on lessons from two science-policy network projects, one focusing on water scarcity in arid and semi-arid regions of Argentina, Chile, Brazil, Peru, Mexico and the United States; and the second addressing river and lake basins as sentinels of climate variability and human effects on water quantity and quality in Canada, the United States, Argentina, Colombia, Uruguay and Chile. Together, these `complementary contrasts' provide an analytical basis to empirically examine stakeholder engagement, knowledge co-production and science-policy interaction supporting decision-making to achieve water security. The paper identifies four tenets for decision-making based on water-security-focused global-change science in the Americas: 1) Decision makers should focus on protecting ecosystems because water security (along with food and energy security) depend on them; 2) Water-use and allocation decisions ought to be made considering future environmental and societal vulnerabilities, especially climate projections; 3) Holistic approaches (at basin or other appropriate levels) are best suited to ensure social-ecological system resilience and reduce vulnerability; and 4) It is essential to support local/traditional livelihoods, and underserved populations to achieve equitable water security and ecosystem resilience.
- ItemModeling Phenology Combining Data Assimilation Techniques and Bioclimatic Indices in a Cabernet Sauvignon Vineyard (Vitis vinifera L.) in Central Chile(2023) Garcia-Gutierrez, Victor; Meza, FranciscoPhenology is a science that is fundamental to crop productivity and is especially sensitive to environmental changes. In Mediterranean and semi-arid climates, vineyard phenology is directly affected by changes in temperature and rainfall distribution, being highly vulnerable to climate change. Due to the significant heterogeneity in soil, climate, and crop variables, we need fast and reliable ways to assess vineyard phenology in large areas. This research aims to evaluate the performance of the phenological data assimilation model (DA-PhenM) and compare it with phenological models based on meteorological data (W-PhenM) and models based on Sentinel-2 NDVI (RS-PhenM). Two W-PhenM approaches were evaluated, one assessing eco- and endo-dormancy, as proposed by Caffarra and Eccel (CaEc) and the widely used BRIN model, and another approach based on the accumulation of heat units proposed by Parker called the Grapevine Flowering Veraison model (GFV). The DA-PhenM evaluated corresponds to the integration between RS-PhenM and CaEc (EKF-CaEC) and between RS-PhenM and GFV (EKF-GFV). Results show that EKF-CaEc and EKF-GFV have lower root mean square error (RMSE) values than CaEc and GFV models. However, based on the number of parameters that models require, EKF-GFV performs better than EKF-CaEc because the latter has a higher Bayesian Index Criterion (BIC) than EKF-GFV. Thus, DA-PhenM improves the performance of both W-PhenM and RS-PhenM, which provides a novel contribution to the phenological modeling of Vitis vinifera L. cv Cabernet Sauvignon.
- ItemNitrogen Application in Irrigated Rice Grown in Mediterranean Conditions: Effects on Grain Yield, Dry Matter Production, Nitrogen Uptake, and Nitrogen Use Efficiency(TAYLOR & FRANCIS INC, 2009) Artacho, Pamela; Bonomelli, Claudia; Meza, FranciscoField experiments were conducted in the major rice growing area of Chile to evaluate the effects of nitrogen (N) fertilization and site on grain yield and some yield components, dry matter production, N uptake, and N use efficiency in rice cultivar 'Diamante'. Two sites (indicated as sites 1 and 2) and six N rates (0, 50, 100, 150, 200, and 300 kg N ha-1) were compared. Nitrogen fertilization increased yield, panicle density, spikelet sterility, dry matter production, and N uptake at maturity. 90% of maximum yield was obtained with 200 kg N ha-1 in site 1 (12,810 kg ha-1) and with 100 kg N ha-1 in site 2 (8,000 kg ha-1). These differences were explained by lower panicle density, and the resulting lower dry matter production and N uptake in site 2. Nitrogen use efficiency for biomass and grain production, and grain yield per unit of grain N decreased with N fertilization. While, agronomic N use efficiency and N harvest index were not affected. All N use efficiency indices were significantly higher in site 1, except grain yield per unit of grain N. The observed variation in N use efficiency indices between sites would reflect site-specific differences in temperature and solar radiation, which in turn, determined yield potentials of each site. On the basis of these results, cultivar 'Diamante' would correspond to a high-N use efficiency genotype for grain yield.
- ItemResearch trends and gaps in climate change impacts and adaptation potentials in major crops(2023) Wakatsuki, Hitomi; Ju, Hui; Nelson, Gerald C.; Farrell, Aidan D.; Deryng, Delphine; Meza, Francisco; Hasegawa, ToshihiroCrop adaptation to climate change is critical for ensuring food security. We systematically reviewed the projected impacts of climate change and adaptation potentials to identify gaps in crop adaptation research. We screened 203 studies of four major crops published between 2021 and 2022. Recent scholarship has increasingly studied sudden yield losses, but the capacity of crop models to reproduce the impacts of extreme events still needs to be improved. Grain quality has rarely been considered. Only four adaptation options accounted for 90% of all options tested. Adaptation potentials, defined as the difference between yield impacts with and without adaptation, averaged 4-5% per degree of warming, but their effectiveness in risk reduction was significantly smaller in the currently warmer regions. The effectiveness of adaptation needs to be assessed using various indicators, including profitability and environmental impact. More adaptation options tailored to each region need to be assessed locally.