Cecilia Conde

Climate and freshwater resources in Northern Mexico: Sonora, a case study.

An analysis of current trends in water availability in the Mexican border state of Sonora is presented to illustrate what may be faced under climate change conditions. Precipitation, streamflow and even dam levels data are examined to estimate what changes have been experienced in recent decades. There are indications that the more frequent occurrence of El Niño/Southern Oscillation (ENSO) events have resulted in more winter precipitation and consequently in a slight increase in water availability in northwestern Mexico. However, water demands grow much faster than such trends in water availability, mainly due to a rapid increase in population in urban areas and in socio-economic activities such as those related to agriculture, industry and power generation. Some strategies to adapt or mitigate climate change conditions are proposed.

The new national climate change documents of Mexico: what do the regional climate change scenarios represent?

This paper presents a review of the methodology applied for generating the regional climate change scenarios utilized in important National Documents of Mexico, such as the Fourth National Communication to the United Nations Framework Convention on Climate Change, the Fourth National Report to the Convention on Biological Diversity and The Economics of Climate Change in Mexico. It is shown that these regional climate change scenarios, which are one of the main inputs to support the assessments presented in these documents, are an example of the erroneous use of statistical downscaling techniques. The arguments presented here imply that the work based on such scenarios should be revised and therefore, these documents are inadequate for supporting national decision- making.

A methodology for the risk assessment of climate variability and change under uncertainty. A case study: coffee production in Veracruz, Mexico

Existing methods for the assessment of the potential impacts of climate change in productive activities and sectors are usually limited to point estimates that do not consider the inherent variability and uncertainty of climatic and socioeconomic variables. This is a major drawback given that only a limited and potentially misleading estimation of risk can be expected when ignoring such determinant factors. In this paper, a new methodology is introduced that is capable of integrating the agent’s beliefs and expert judgment into the assessment of the potential impacts of climate change in a quantitative manner by means of an objective procedure. The goal is to produce tailor-made information to assist decision-making under uncertainty in a way that is consistent with the current state of knowledge and the available subjective “expert” information. Time-charts of the evolution of different risk measures, that can be relevant for assisting decision-making and planning, can be constructed using this new methodology. This methodology is illustrated with a case study of coffee production in Mexico. Time-dependent probabilistic scenarios for coffee production and income, conditional on the agent’s beliefs and expert judgment, are developed for the average producer under uncertain future conditions. It is shown that variability in production and income, generated by introducing climate variability and uncertainty are important factors affecting decision-making and the assessment of economic viability that are frequently ignored. The concept of Value at Risk, commonly applied in financial risk management, is introduced as a means for estimating the maximum expected loss for a previously chosen confidence level. Results are tailor-made for agents that have incomplete information and different beliefs. In this case study, the costs of climate change for coffee production in Veracruz are estimated to have a present value representing from 3 to 14 times the current annual value of coffee production in the state.

Exposure to climate and climate change in Mexico

An index with the potential to integrate different climate hazards into a single parameter is required to guide preventive decision making. We integrated in a single index the degree of exposure to climate that the nations municipalities have. We selected this spatial scale because the municipality is the basic unit of administrative and economic planning; consequently, this is the scale at which policies of adaptation to climate change must be fostered. We conceptualized exposure as the sum of historic extreme events, the degree of ecosystem conservation and current climate and its future scenarios. This approach allowed us to create a climate hazard exposure index at the municipality scale integrating past and present. Maps of this index can be constructed to serve as a medium of risk communication and to aid policy design. We used information from eighteen variables to statistically standardize and compute the hazard exposure index by applying empirical formulae. We found that actually, out of ten Mexicans, three live in flood-prone zones, three may suffer the passage of tropical cyclones, five reside in drought zones and two live in extreme drought regions. Additionally, hailstorms affect five out of ten Mexicans, while eight out of ten are affected by frosts. Incorporating climate change, in the future more municipalities and a higher population will live in high exposure. Because understanding exposure is a necessary prerequisite to understanding vulnerability, knowledge of the spatial distribution of exposure should be useful for reducing the identified climate hazard exposure and vulnerability to climate change.

Climate Variability and Climate Change, and Their Impacts on the Freshwater Resources in the Border Region

Climate change scenarios and recent studies on climate variability refer to important low-frequency variations of precipitation regimes for the northern regions of Mexico. Data on precipitation, streamflow, and water levels in storage reservoirs are used to analyze tendencies and changes in water availability during the last 30 years. El Nino/Southern Oscillation (ENSO) events become of particular interest since El Nino boreal winters generally result in more precipitation and increased water availability in northwestern Mexico. However, summer precipitation in the region does not show a clear El Nino signal. Furthermore, the interannual variability of precipitation associated with the Mexican monsoon does not appear to be modulated by sea surface temperature (SST) variations.

Adaptive capacity: identifying the challenges faced by municipalities addressing climate change in Mexico

In many countries, administrative and economic planning occurs at the municipality level. We believe that relevant policies for adapting to climate change can be initiated at this level. Thus, this article assesses the adaptive capacity of Mexican municipalities and populations to address climate change to measure the challenge that climate change represents. The method was developed as follows. We selected 19 indicators organized into four categories: human, social, financial, and natural. The information was standardized, and we used empirical formulas to obtain an adaptive capacity index. The index was mapped, and the distribution showed the spatial capacity for the adaptation of Mexican municipalities. We discuss the contributions these indicators made to the adaptive capacity and show that the human capital variables were the most relevant for defining the adaptive capacity of municipalities. We also applied this index to the observed climate exposure and sensitivity of Mexican municipalities to climate change. Thus, we propose a matrix to measure the dimensions of the challenges posed by climate change in terms of both decision-making and policy management for increasing the adaptive capacity of municipalities and populations within a nation.

Analysis of indices of extreme temperature events at Apizaco, Tlaxcala, Mexico: 1952-2003

In recent years in Mexico and around the world, the scientific community has shown great interest in acquiring knowledge regarding the behavior of extreme climate events due to their increasing number and intensity. The objective of this research was to analyze variations in extreme temperature events using extreme climate indices. We conducted a case study for the municipality of Apizaco, Tlaxcala, Mexico, using data sets of the daily maximum and minimum temperatures for the period from 1952 to 2003. Six indices related to maximum and minimum temperatures were calculated: frost days, summer days, warm days, cool days, warm nights and cool nights. All of the index results were evaluated annually and only four of the indices were analyzed according to the seasons. A trend based on a linear least squares regression model was fit to the indices to determine their behavior. The index results showed that extreme events related to maximum temperatures corresponded to greater changes and an increased number of summer days and decreased cool days. Additionally, there was an increase of frost days, associated with a greater number of days with minimum temperatures below 0 oC. In general, the results indicated that warmer and colder extreme temperatures are occurring. The detection of those trends in the extreme events can be seen as a first step in any study of the attribution of those observed changes (e.g., land use change, regional climate change, etc.). This attribution aspect will not be discussed in the present study.

Coping with Climate Change Impacts on Coffee and Maize for Peasants in Mexico

In the Mexican states of Tlaxcala (figure 65.1; no. 29) and Veracruz (no. 30), two case studies cases were developed to assess the impacts and possible responses to climate change and climate variability on maize and coffee producers. These two types of producers have differences but also similarities.