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Mexico is vulnerable to extreme climatic events; however, their impact is not uniform in all the country. This study presents an analysis of extreme temperatures in 12 Mexican cities, modeled under the assumption of a non-stationary climate. Temporal trends were estimated from an available climatological base of maximum and minimum temperatures with the non-parametric tests of Mann-Kendall and Sen’s slope method, and a generalized extreme value (GEV) distribution was used to model both temperatures. A likelihood ratio test and Akaike and Bayesian information criteria were used to evaluate the optimal model choice with incorporation of a covariate. Using the best model, return levels and confidence intervals for future scenarios were estimated. A trend towards urban warming was detected from both the non-parametric tests and the GEV distribution, although with heterogeneous behavior. In the series of the maximum temperatures, half of the cities analyzed were non-stationary, and of those, the city of Guadalajara, located in the center-west of the country had a negative trend. The trend for minimum temperatures was more uniform, as 90% of the cities were non-stationary with a positive trend, and only 10%, in an urban area to the east of the metropolitan area of the Valley of Mexico (Milpa Alta) and a coastal city of the Gulf of Mexico (Veracruz), showed stationary series. It is therefore concluded that return periods of thermal extremes estimated in a changing climate temporarily showed a significant variation, so statistical modeling must consider this behavior due to its importance for risk assessments and adaptation purposes.

In cities with dry arid climate, air conditioning (AC) equipment is necessary for thermal comfort in indoor spaces. The use of this equipment generates an increase in electricity consumption and an increment in CO₂ emissions to the environment, thus, one way to mitigate these negative effects is the Living Green Wall (LGW). The objective of this research is to assess the decrease in thermal gain, energy benefits, and estimate the greenhouse gas (GHG) emissions that are not emitted by the use of the LGW. Measurements of heat flux, solar radiation, and temperatures were made on a concrete wall and another with an LGW in a west-facing building in the city of Mexicali, Mexico. The results indicate that it is possible to reduce 49% of the heat flow through the wall, which reduces the thermal load 102,212 Btu/h to the indoor space, implying the additional work of 8.53 tons of AC. This excess equals 985.6 kWh of electrical energy and generates a total of 697 kg of CO₂ emissions during the warm season. It is concluded that shading with an LWG becomes a very influential element to mitigate the heat fluxes towards the indoor spaces.

Global studies focusing on climate extremes in urban areas, specifically in Mexico, have not been approached with a sufficient level of detail, despite considerably increased risks for both infrastructure and human society. Based on 14 climate indices proposed by the Expert Team on Climate Change Detection and Indices (ETCCDI) and the application of the nonparametric Mann-Kendall and Sen’s slope tests, the observed trends of climate extremes in 16 urban areas in Mexico from 1980 to 2010 were analyzed. The results show that climate conditions over most cities of Mexico are changing, as indicated by a warming trend during the study period. Significant increases were detected in the annual average maximum temperature (TMX) and the annual average minimum temperature (TMN). There is no clear trend that the warmest days (TXx) are increasing, but the annual number of warm days (TX90p) and summer days (SU) has increased, and the cold days (TX10p) have decreased. Associated with these changes are concomitant decreases in fewer coldest nights (TNn), an increase in the percentage of days with warm nights (TN90p) and tropical nights (TR), and a decrease in the number of frost days (FD). In contrast, the analysis reveals a statistically significant decrease in the mean temperature and the amount of warm days in Mexico City, which could be associated with the increasing trend of atmospheric pollution and the continuous smoke and ash emissions from the volcano Popocatepetl, which disperse incoming solar radiation and reduce radiative forcing. Climate change indices based on daily precipitation data show positive trends in many cities. In general, an increasing trend in very wet days (R95p), a number of very heavy rainfall days ≥ 25 mm (R25), and the annual total wet days (PRCP) were observed. These results highlight the vulnerability of cities confronted with both global and local climate change and the importance of promoting effective local risk reduction measures as part of urban planning for city dwellers.

This paper presents a hypothetical and comparative performance of a 5 ton air conditioner (AC) operating in two zones in different urban microclimates for 25 days. One site represents a type of homogeneous planned urbanism and the other is a traditional heterogeneous zone. Air temperature data was collected and then processed using a linear regression model included in the operating manual of the AC in order to obtain their energy consumption. Results indicate that for an area with 500 homes, a traditional urban complex requires 12,350 kWh of electrical energy more than a planned zone (1.89%). This extra energy amounts up to $1180 and adds 9191 kg of CO2 to the atmosphere. The increased energy consumption has implications that increase the cost and environmental aspects of two urban microclimates, so that urbanization without planning is less friendly to the environment. In this sense, this study highlights the effects of urban microclimates on domestic electricity consumption from air conditioning. In addition, for a city with an arid desert climate, the variation in electricity consumption is associated with changes in the urban mosaic. The results found represent scientific evidence that can be used as a reference to establish public policies that could be incorporated into the local construction regulations, oriented to reduce the energy consumption associated with the use of air conditioning equipment.

Electronic waste is a widespread environmental problem. From all waste streams, e-waste is registering one of the largest growing rates (between 3% and 5%). In Mexico, the e-waste recovery system comprises a mix of formal and informal sectors not well known to date. The goal of this article was to analyze electronic waste in Mexico through the active actors in the recovery chain. This article presents the evolution of studies on electronic waste in Mexico. The legal regulations and public policies were analyzed, as were the existing practices of electronic waste handling, and some challenges facing this country for waste flow management. A management model is proposed which highlights components that must be considered in the model and the opportunities and challenges to transition from an unbundled handling, which still has practices that lack environmental and technical support, to sustainable management.

The generalized extreme value distribution is applied in this article to model the statistical behavior of the maximum and minimum temperature distribution tails in four cities of Baja California in northwestern Mexico, using data from 1950–2010. The approach used of the maximum of annual time blocks. Temporal trends were included as covariates in the location parameter (μ), which resulted in significant improvements to the proposed models, particularly for the extreme maximum temperature values in the cities of Mexicali, Tijuana, and Tecate, and the extreme minimum temperature values in Mexicali and Ensenada. These models were used to estimate future probabilities over the next 100 years (2015–2110) for different time periods, and they were compared with changes in the extreme (P90th and P10th) percentiles of maximum and minimum temperature scenarios for a set of six general circulation models under low (RCP4.5) and high (RCP8.5) radiative forcings. By the end of the twenty-first century, the scenarios of the changes in extreme maximum summer temperature are of the same order in both the statistical model and the high radiative scenario (increases of 4–5 °C). The low radiative scenario is more conservative (increases of 2–3 °C). The winter scenario shows that minimum temperatures could be less severe; the temperature increases suggested by the probabilistic model are greater than those projected for the end of the century by the set of global models under RCP4.5 and RCP8.5 scenarios. The likely impacts on the region are discussed.

El mercado de telefonía móvil ha experimentado un continuo crecimiento en la última década. Cada vez más, los teléfonos móviles son reemplazados por nuevos modelos con diseños más modernos y ampliación de funciones. Este estilo de vida está provocando incremento en la cantidad de residuos de aparatos electrónicos que no siempre reciben tratamiento. Por lo que, en este artículo, se presentan los resultados de la aplicación de la metodología de análisis de ciclo de vida (ACV) para calcular cuantitativamente el beneficio ambiental debido a la extensión de vida útil del teléfono móvil durante diferentes períodos. Tomando como unidad funcional el ciclo de vida promedio de 30 meses, se modelaron tres escenarios considerando cuatro etapas: adquisición de materias primas/producción, distribución, uso y fin de vida útil. Se utilizó el paquete SimaPro (2013), la base de datos Ecoinvent para configurar el inventario y las emisiones consideradas se asignaron en seis categorías de impacto según el método CML2000 del Centro para Estudios Medioambientales (CML). Se observó que al prolongar la vida útil del teléfono móvil y dar tratamiento cuando se convierte en residuo representa una ganancia ambiental no sólo porque se evita su disposición y consumo de uno nuevo, sino porque se ahorran recursos limitados y la energía necesaria para su extracción a través de la recuperación de materiales. Sin embargo, antes de reciclar es importante considerar su reutilización (extensión de su vida útil) ya que una cantidad sustancial de los móviles son dispuestos por razones de moda o estética mientras aún son funcionales. The mobile phone market has experienced continuous growth over the last decade. Increasingly, mobile phones are replaced by new models with more modern designs or expansion of functions. This lifestyle is causing increasing amount of electronic waste that do not always receive treatment. This article presents the results of the application of the methodology for life-cycle assessment (LCA) to calculate quantitatively the environmental benefit due to the extension of lifespan mobile phones during different periods of time. Taking as a functional unit the life cycle of an average mobile phone during 30 months and considering the stages of raw materials/production, distribution, use and end of life, three scenarios were modeled. The SimaPro (2013) software was used, the Ecoinvent database has been applied to configure the life cycle inventory, and the emissions were allocated into six categories according to the impact CML2000 method. It was observed that to extend the mobile phone useful life and to provide treatment when it becomes a waste, represents an environmental gain not only because the provision and consumption of a new one is avoided, but because limited resources and energy required for extraction are saved through recovery of materials. However, before recycling it is important to consider reuse (extending lifespan) because a substantial amount of the mobile phones are discarded for fashion or cosmetic reasons while they are still functional.

The waste derived from Electrical and Electronic Equipment (WEEE) is of interest now worldwide, in some countries due to the rapid technological development and in others due to technological dependence through the acquisition of second hand equipment. Therefore it is necessary to implement strategies for the sustainable management of electrical and electronic equipment at the end of its useful life. This paper presents the results of an investigation that was conducted in a city located in the Northwest of Mexico, which seeks to understand the management practices of household WEEE generators. A survey was applied to a representative sample of the population with a confidence level of 90%. Six home appliances were quantified and it was found that approximately 21% of them are disposed directly as part of the household flow of Municipal Solid Waste (MSW), while 79% are storage for a latter sale, repair or reuse. The results obtained support the need to develop evaluations and to implement possible scenarios for the sustainable management of Electrical and Electronic Waste.

The most severe impacts of climate on human society and infrastructure as well as on ecosystems and wildlife arise from the occurrence of extreme weather events such as heat waves, cold spells, floods, droughts and storms. Recent years have seen a number of weather events cause large losses of life as well as a tremendous increase in economic losses. According to the IPCC (2007), an extreme weather event is an event that is rare at a particular place and time of year. Definitions of rare vary, but an extreme weather event would normally be as rare as or rarer than the 10th or 90th percentile of the observed probability density function. Changes in frequency or/and intensity of extreme events can affect not only human health, directly through heat and cold waves and indirectly by floods or pollution episodes, but also for example, on crops or even insurance calculations. Climate extremes associated with temperature (heatwaves) and precipitation (heavy rain, snow events, droughts) can also affect energy consumption, human comfort and tourism and are responsible for a disproportionately large part of climate-related damages (Easterling et al., 2000; Meehl et al., 2000). Extreme weather events recorded in recent years, and associated losses of both, lives and economics goods, has captured the interest of the general public, governments, stakeholders and media. The scientific community has responded to this inquiry and has raised interest in studying with more attention to detail. Our understanding of the mean behavior of climate and its normal variability has been improving significantly during the last decades. In comparison, climatic extreme events have been hard to study and even harder to predict because they are, by definition, rare and obey different statistical laws than averages. In particular, extreme value analysis usually requires estimation of the probability of events that are more extreme than any that have already been observed, and they are linked to small probabilities. Climate extremes can be placed into two broad groups: (i) those based on simple climate statistics, which include extremes such as a very low or very high daily temperature, or heavy daily or monthly rainfall amounts, that occur every year; and (ii) more complex event-driven extremes, examples of which include drought, floods, or hurricanes, which do not necessarily occur every year at a given location. Katz & Brown (1992) first suggested that the sensitivity of extremes to changes in mean climate may be greater than one would assume from simply shifting the location of the climatological distributions. Since then, observations of historical changes as well as future

El clima de cualquier región es afectado por influencia antrópica cuando se cambia el uso de suelo nativo, como por ejemplo, cuando se establecen tiraderos de basura en las periferias de las ciudades. La respuesta térmica de esta modificación es el resultado de la composición de suelo heterogéneo del sitio que se integra a los procesos de la atmósfera baja al interactuar con el ambiente. Como resultado se promueven la generación de microclimas, no siempre deseables, dentro de la región. En esta investigación se presenta un análisis de las componentes radiativas superficiales y temperaturas del suelo sobre una cobertura de residuos sólidos municipales situado en las afueras de la ciudad de Mexicali, B.C., México. Se realizan mediciones con instrumentación que usualmente se utilizan para evaluar balance energético en la atmósfera baja, complementada con mediciones de temperatura de suelo realizadas con una cámara de imágenes en infrarrojo siguiendo transectos determinados previamente. Las campañas de medición se llevaron a cabo durante un horario matutino con el fin de obtener el comportamiento sin ganancia solar y en las primeras horas del mediodía cuando se tiene la máxima ganancia solar. La radiación neta, el albedo y la temperatura del suelo en el basurero se comparan con los obtenidos del suelo circundante sin perturbación por el basurero encontrándose diferencias importantes, las cuales pueden ser atribuidas al cambio local en el uso del suelo, las propiedades biofísicas de los materiales y el poder calorífico de los residuos depositados en el vertedero. Se discuten las afectaciones potenciales del bioclima en las comunidades circundantes.