Urban Climates in Latin America

The large cities (at least five million inhabitants) in Latin America have grown in terms of both population and spatial extent and have modified the climate more drastically than medium to small cities. These modifications include surface and atmospheric urban heat islands, air pollution, dry islands, etc. Furthermore, the distribution of these modifications in cities follows the morphologies acquired by the various sectors of the city, which are defined as local climate zones. This chapter contains an exhaustive review of the literature of the eight larger cities of Latin America and a presentation of some of the differences and similarities between them and their urban climates. The authors have concluded that not all the large Latin American cities have been studied with the same intensity and that, therefore, the results for the various cities are quite different. Nevertheless, the intensities of the heat islands in these large cities have been found to vary between 3 °C and 8 °C, and population density and latitude offer partial explanations for these differences between urban and non-urban temperatures. A pending task for the large Latin American cities is the incorporation of the new analytical methodologies that are currently proposed with regard to local climate zones.

Sustainable urbanization remains one of the central challenges for South America. Cities of this region are expanding very fast and this impressive urban growth has a significant impact on the environment, on energy consumption, and on public health. This chapter explores the urban heat island (UHI) effect on the climate of Guayaquil, Lima, Antofagasta, and Valparaíso. These four cities are important urban centers on the Pacific coast of South America. The UHI effect is simulated by using the Urban Weather Generator tool (UWG), a coupled atmospheric–building simulation model that uses urban form parameters to transform rural weather files into urban weather files. Urban form parameters considered in the analysis are the built-up ratio, the facade ratio and the green area ratio, obtained for 24 one-hectare random samples and running a principal component analysis and a k-mean cluster to group them. Simulation results show the presence of a UHI effect that varies between 2 and 5 °C during the night and a more dispersed situation during the day. Valparaíso and Guayaquil seem to have higher UHI than Lima and Antofagasta, probably because of the difference in the temperature ranges (higher maximum temperatures). Some hypotheses regarding the influence of the Pacific Ocean, such as urban form, heat generation in the street, building energy use, impervious materials on the resulting UHI effect are formulated and discussed, along with an estimation of the impact on the built environment looking at energy consumption, comfort felt by users, and vulnerability to heat waves.

Promoting the generation of sustainable cities is the main objective of an urban climatologist. To incorporate urban climate knowledge into urban planning, it is necessary to create instruments that summarize the relationship between meteorological parameters and urban form and function. This chapter shows the urban climate of the city of Tandil, Argentina, and its relations with land cover. The main objective is to present an instrument that proposes improvement in urban planning using this information.

The instrument was generated combining two methodologies: local climate zones (LCZs) and climatopes. LCZs are used to characterize the different urban forms and functions. They were created based on construction and population density, the amount of vegetation, location characteristics and temperature, and spatial and temporal distribution. To summarize urban climate information, climatopes were made using seasonal temperature, humidity and precipitation distribution, wind analysis, and comfort. The results are presented in a map and a table.

Tandil is a middle-sized city located in the south east of Buenos Aires province, Argentina. It has a transitional temperate climate and is surrounded by the Tandilia Hill System. The city has a population of 116,916 inhabitants and diversified economic activity.

As a result, 16 LCZs were determined and climatic characteristics were described for each of them. The analysis of each one put into context the need to improve existing urban planning, which does not take into account climatic parameters. The mitigation strategies consisted in three types of intervention: gas emission control, improving urban vegetation, and construction restrictions.

The bioclimatic comfort is a state of complete physical, mental, and social well-being of the individual in relation to its environment, relevant in tourists and residents of coastal cities such as Mar del Plata, as its temperate climate contributes to alleviating high temperatures in other corners of the country and generates a feeling of comfort, favorable to rest and the development of various outdoor activities. The Humidex index (sensation of overwhelming or embarrassment perceived by people owing to the lack of evaporation of body humidity) was calculated to evaluate summer comfort/discomfort, based on hourly temperature and relative humidity data recorded on 18 January 2014 and 28 December 2015, identifying the periods of comfort and/or urban discomfort observed on those days. Some spatial differences were also evaluated and explained from data from three meteorological stations in the city. The results obtained, especially those on heat discomfort and its effects on the health of urban dwellers, especially children and the elderly, justify incorporating this index into the daily meteorological information of the media during the summer.

One way of evaluating the impact of urban climate on human health and the quality of life is through the sensation of thermal comfort, which depends on a series of parameters, such as the physiological, psychological, meteorological, and morphological factors of the city. In this context, this chapter focuses on evaluating and integrating the measurement of instrumental comfort, perceptual comfort, and urban morphology in public spaces for two Chilean cities. For this purpose, pedestrian urban canyons representative of the city centers are selected: the pedestrian walkway Arauco in the city of Chillán and the pedestrian walkway Barros Arana in the city of Concepción. The survey was carried out during the months of January 2016 and February 2014 and included meteorological parameter measurements of atmospheric temperature, relative humidity, wind speed and direction, in 2-h intervals. The comfort indicators of Olgyay, the Temperature–Humidity Index, and the Actual Sensation Vote were calculated. In addition, a survey of comfort perception was conducted according to an adaptation of Cheng’s proposal. For the purposes of urban morphology, three-dimensional constructions and vegetation were modeled. A significant correlation is observed between instrumental indicators and perceived comfort; this is clearly demonstrated by the greater discomfort declared by permanent residents of Chillán. The importance of planning the structure and urban morphology of the canyons stands out as it regulates heights; materiality and green spaces that help to reduce the causes of discomfort in the summer. More studies are needed to determine winter comfort.

Air pollution is currently the most serious environmental risk worldwide. Air pollution is the result of different driving forces (demography, economic growth, consumption patterns, energy options, cultural traditions, etc.) constrained by climate conditions, urban shapes and development patterns, distance to industrial or mining activities, air quality regulations and plans, etc. Air quality has been improving in some of the largest cities in Latin America, yet in most of them ambient air quality standards are not attained. In Brazil, Chile, Ecuador, and Mexico, the most polluted city is not the country’s capital, emphasizing the relevance of sustainable local governance. In countries that report air quality just for their capital cities, most of their pollution levels are above the respective national ambient air quality standards. There is less information for mid-sized cities, and the available results are mixed. We present case studies from several countries that show serious air quality exposure for millions of inhabitants, especially the low-income segment. We discuss environmental justice, urban governance, and citizen participation in decision-making processes, sustainable urban transport options, and gender issues throughout those case studies.

Most Latin American cities have air quality problems owing to high levels of particulate matter and ozone. By 2050, it is expected that more than 80% of Latin Americans will live in urban areas, leading to an increment in pollution problems. Santiago, Chile shows a high level of pollution from PM₁₀ and PM_2.5, especially during the autumn–winter period and from ozone (O₃) during the spring–summer period owing to natural and anthropogenic causes. Information for this chapter was obtained from the official monitoring system of pollutants, but also from scientific papers and experimental work developed in our laboratory. The chapter contains a general description of the particulate matter, some analytical methods of studying it, and their officially reported sources; also, some new findings are included. For tropospheric ozone, a similar procedure was followed. The result is essentially focused on considering the ability of urban trees in capturing PM, while at the same time emitting minimal amounts of biogenic volatile organic compounds (BVOCs) that can potentially generate ozone. Available information shows that native species and a few exotic species were the most frequently appropriated to accomplish both requirements. As the vegetation of Santiago is mainly composed of exotic tree species that lose their leaves during the winter and produce high quantities of BVOCs during spring–summer, it does not contribute to the improvement of air quality; on the contrary. This situation should be remedied as soon as possible through the correct choice of trees and urban planning measures. The chapter also includes some similar variables reported in the literature from other countries of Latin America.

Rapid urbanization and countryside depopulation in Chile, as in the whole of Latin America, has not been accompanied by the available resources, urban planning and management necessary to supply urban societies and spaces with the required services and environmental quality. Although Chile currently has one of the highest indicators of per capita income and human development index in Latin America, and it has achieved some of the lowest poverty figures, Chilean cities still have neighborhoods where poverty is linked to a lack of opportunities and equipment, and higher insecurity levels that result from combining natural and socio-economic threats. The poor people live in places with urban heat islands, where a lack of vegetation dries the air and generally occupy areas with less ventilation, which, consequently, lead to a higher concentration of air pollutants. In contrast, richer inhabitants are used to living in areas of urban cooler islands, where temperatures are not as high because of the presence of gardens, urban forests, and parks. First, this chapter addresses the spatial relationships between land uses/cover changes and surface temperatures in Santiago de Chile. Second, such urban internal differences are represented by local climate zone (LCZ) analyses for some of the Chilean cities located throughout the country: Calama, Antofagasta, Valparaíso, Santiago, Concepción, and Chillán. Three cases of land use changes in Santiago neighborhoods (LCZs) are described and related to socioeconomic conditions. Urban heat islands and heat waves in Santiago are examined. Finally, the relationship between the spatial distribution of particulate matter, temperatures, urban geography, and socioeconomic groups are shown.

Despite their individual socio-spatial paths of development, the countries of Latin America underwent similar urbanization processes. Analyzed from the geographical perspective of the spatial relationship between society and nature, the different forms of urbanization, especially in their material dimension, directly affect the creation of different climates. Based on this assumption, Carlos Augusto de Figueiredo Monteiro originally proposed, in his associate professorship thesis, the Urban Climate System (UCS) theory in Brazil with the goal of analyzing the climates of specific locations and their urbanization. Based on the work by Monteiro, combined with a climate geographical perspective, the goal of our study was to analyze the urban climate, specifically the hydrometeorological subsystem that triggers extreme events in the urban portion of Rio de Janeiro, Brazil. First, the specifics of urbanization of a Latin American metropolis underlining the particularities of its urban climate are briefly introduced. Subsequently, the UCS theory is presented, focusing on the perceptual channels and the specifics of flood events, which is followed by a characterization of the climate dynamics of the study area, including those that occur on an hourly scale. Last, the hours of highest precipitation are identified, and the ways in which social groups are related to the urban climate of Rio de Janeiro are explained.

This chapter reports trends in climate extreme indices (CEI) and comfort indices for the period 1965–2015 and its relationship to historical disasters associated with hydrometeorological events for several Chilean cities. CEI analysis focused on differences in temperature trends and precipitation indices proposed by an Expert Team on Climate Change Detection, Monitoring, and Indices using RClimdex software. The disaster database had been obtained from journals, documents, and the DesInventar platform for 50 years. The results indicate that the minimum temperature increased in most parts of the country and frost events (TNn, CSDI3, and FD0) are decreasing. The heat extremes (TXx, SU30, and SU35) are decreasing in cities located in northern Chile, but increasing in central and southern Chile. The heatwaves (WSDI3 and HWN) have shown a decreasing trend in northern cities located near the coastline and an increasing trend in the rest of the cities, especially those located more centrally and in an inland position, such as Santiago and Chillán. Precipitation (RX3day, RX5day, R20mm, R50mm, and R95p) has decreased, but is more concentrated; and precipitation total (PRCTOT) and the consecutive number of dry days (CDD) are increasing according to the latitudinal gradient of cities. Furthermore, in the last 50 years, urban cities have been affected by approximately 682 natural disasters. The greatest amount of natural disasters occurred during 1991 and 1997, mainly because of precipitation. Both the extreme events and the high frequency of natural disasters show trends toward climate change, but these trends are strongly influenced by natural climate variability and events such as El Niño–La Niña.

Dengue is currently one of the most serious worldwide public health problems. It is considered an neglected urban tropical disease by the World Health Organization, and Latin America has the ideal environment conditions for the proliferation of the Aedes mosquito (Aedes aegypti and albopictus), vector of the disease. Moreover, the urbanization, lifestyle, and ineffectiveness of public health policies have resulted in severe epidemics. This research focuses on analyzing the influence of the urban climate and the proliferation of dengue in three different cities in Brazil: Campo Grande, Maringá, and Ribeirão Preto, correlating climatic variables with the incidence of the disease through the use of GIS and modeling tools to understand the dynamics of the urban climate. The analysis of daily temperature showed significant correlation (R = 0.70 and P > 0.99) with the records of the disease and a delay of 7 days, just as there is a good correlation between the end of the rainy season and the epidemic peak. The results show the complexity of the disease, in a close relationship among the environment, the circulation of different serotypes, solid waste disposal, rubble, and abandoned pools, which puts its own population at risk and vulnerable to disease. An important point is that, even in different cities, the epidemic followed a similar pattern, emphasizing the importance of climate variables in an epidemiological understanding of this process. From the results, it is expected that study helps local health agencies in implementing appropriate early warning systems from monitoring and preventive control of environmental conditions.

Green infrastructure (GI) offers a new perspective on the benefits of urban and peri-urban green spaces. In Latin America, the urbanization process has involved a loss of these green spaces of high environmental value. These changes have had a series of consequences on the climate of Latin American cities that have been intensified by climate change. Although the contribution of GI to urban climate regulation and to climate change mitigation and adaptation is growing in recognition, the debate has still had little influence on urban planning initiatives, with exceptions in North America and Europe. In Latin America and Africa little is known about how climate change adaptation plans incorporate the development of urban GI. This chapter explores institutional actions to develop GI as an alternative to tackle climate change in Latin American cities. A bibliographic review was conducted using the terms “green infrastructure” or “climate change.” The analysis focused on identifying: responsible institutions, objectives, and the understanding and use of the GI concept. Results indicate that GI has been recently and slowly incorporated into urban planning. This scenario suggests a growing awareness of the need to plan sustainable, green, and more prepared cities to face climate change. However, planners have not considered enough the potential contribution of GI; thus, the role of GI has not been properly identified and valued in urban planning, and planning and design efforts do not maximize the benefits of GI.

Although Uruguay undertakes many actions at the national level to tackle extreme phenomena in climate change, such as the creation of the National Plan on Climate Change, most of the attention was given to the Energy Reconversion Plan, or agriculture insurance facilities for Climate Change Disaster. In a local urban context, however, extreme climate events, mainly floods and droughts, have had less attention but concrete adverse effects on many urban areas, particularly on the most vulnerable communities (population and infrastructure) and on climate-dependent basic services and economic activities. This chapter describes the current policies and initiatives taken regarding climate change at an urban level. We can identify the birth of a new institutional framework, which is creating a methodology to create a dialogue with the main changes in Territorial and Urban Planning at an international level. The chapter also focuses on the main case studies in the capital city, Montevideo, in particular the Urban Plans for Streams and Basins, which dialogue with Local Plans for urban renewal, including climate change issues. In addition to this, a focus on the Metropolitan Plan on Climate Change shows how from a methodological point of view an innovative participatory methodology has been developed considering the necessary actor’s network to be established toward the implementation of the adaptation measures. Finally, some important considerations are made, thinking critically about how to include all the new strategies to deal with climate change, resilience, and sustainable development from a long-term perspective on a multi-level scale, national, metropolitan, and local.

Globalization and urbanization have been two forces that have spread around the world in an accelerated form and without adequate planning in the localities where their impacts are greatest. In the case of Latin America, this is especially evident in small and intermediate towns and cities. Climate change is another force that combines with globalization and urbanization, generating severe impacts and major challenges for integrated planning. In this chapter, a preliminary rapid appraisal tool is provided as a first step for climate risk assessment. The methodology includes six stages, and is developed with the goal of identifying the climate risk hotspots, and existing and potential local responses. A pilot application was carried out in the city of Florencia, in south west Colombia. The results provide inputs for the formulation of local development strategies and policies, acting as a platform for initiating climate change adaptation.