Coastal vulnerability and adaptation to climate change

Given that a global change is coming that will affect the climate, the hydrological cycle, and the way it rains, some things need to be done to make people and the environment less vulnerable. This will help communities be better prepared to deal with natural disasters and get back to normal as soon as possible if they do happen.

The Intergovernmental Panel on Climate Change (IPCC) defines vulnerability as the propensity or predisposition to be negatively affected. In 1988, the United Nations (UN) put together this group of international experts to help people understand the technical and scientific information about climate change, its causes and effects, and possible actions and strategies to deal with it.

In this sense, the IPCC has become the main reference on climate change (CC), and many governments, including the Mexican government, generate their CC strategies following the guidelines set by this international agency. In Mexico, the National Institute of Ecology and Climate Change (INECC) states that it follows the conceptual framework proposed by the IPCC (2007), expanding the previous definition, indicating that vulnerability is the degree of susceptibility or incapacity of a system to face the adverse effects of climate change and, in particular, climate variability and extreme phenomena. It also says that a system's vulnerability will depend on the type, size, and speed of climate change to which it is exposed, as well as on how sensitive it is and how well it can adapt.

In addition, INECC highlights, within the institutional actions and programs, the issue of vulnerability and adaptation to climate change, focused on generating strategies to address the risks of climate change through mitigation and adaptation actions with a territorial and systemic vision. To achieve this objective, it is based on three methodological approaches that incorporate considerable transdisciplinary research work: ecosystem-based adaptation (EbA), community-based adaptation (CBA), and adaptation based on disaster risk reduction (AbRRD). Based on these three approaches, the goal is to make regions less vulnerable, increase their ability to adapt, find ecosystems and species that are at risk because of climate change, and bring back the functionality of watersheds and landscapes through the conservation, restoration, and sustainable use of natural heritage.

From the information generated by these institutions, some points stand out as basic for any vulnerability analysis focused on CC. Firstly, we wish to emphasize the unquestionable presence of climate change, despite the existence of ideological currents that deny it, particularly about the role played by humans in driving it. According to the most recent IPCC AR5 synthesis report, the following conclusions are reached:

• Climate change is unmistakable, and the influence of human activities is clear. The more we disrupt our climate, the more we risk severe, widespread, and irreversible impacts. In that sense, it is very likely that heat waves will occur more frequently and last longer, and that extreme precipitation events will become more intense and frequent in many regions.
• We can stop climate change and build a more prosperous and sustainable future if we have the right tools, the right ways to run things, and better ways to respond.

As a result of the above, it is clear that the intensification of climate change will make some of its main expressions more noticeable, such as the warming of the oceans and the increase in the average sea level, the acceleration of melting ice at the poles, and the increase in extreme meteorological phenomena.

Each of these manifestations will directly or indirectly affect the human population, which will perceive their negative effects differently and at different magnitudes in different regions and environments of the planet.

There may be short-, medium-, and long-term effects of global change. Extreme weather events like droughts and storms may be the most obvious and worrying, since they are likely to become more common, severe, and intense, causing damage right away and over time.

The fact that any population could be damaged by extreme events, especially heavy rains, shows how vulnerable it is. This is the main focus of this work, even though it is limited to the coastal zone, and it looks at populations not as separate social entities but as parts of socio-ecological systems, in which the survival, presence, resilience, and health of all their parts will lead to a better future.

For all of the above reasons, this work seeks to provide an integrated approach to the analysis of vulnerability derived from a climatic hazard, in this case, heavy rains, involving not only the social component, i.e., the human populations exposed and their response capacity, but also the environmental factors that define them.

So, it's important to include ecosystem services (ES), which are the many benefits and services that ecosystems provide to societies, such as food, water purification, pollutant trapping, and flood protection. These services also help people's well-being by giving them security, good health, and the things they need to live a good life.

Even though ES as a whole is about the benefits of the natural capital of the coastal zone, this work focuses on wetlands because of their ability to protect against rain, coastal erosion, and flooding. They also provide food and shelter, clean water and air, and help control the environment's temperature. All of these things are important to the resilience of coastal systems and, by extension, their ability to adapt to changes.

Additionally, it is important to point out that in this work reference is made to northwestern Mexico as the geographic area of study, where it is foreseen that there are high possibilities of increasing its vulnerability in the short term, due to the accelerated population growth along its coasts and the intensification of diverse environmental factors resulting mainly from climate change and the transformation of the natural landscape, as will be seen in the different topics discussed here.

Vulnerability in coastal areas

Once the issue of climate change became part of the scientific discourse as one of the main threats worldwide, numerous contributions were made to understanding the causes of the process, its effects, and possible future consequences. In particular, the issue of the rise in the average sea level is the most worrying. This has been known since the turn of the century when the IPCC put together data from the end of the 19th century.

In this sense, although climate change affects the entire world, the coastal zone is possibly the region that has aroused the most significant concern, since it is there that many of its effects are reflected with the greatest intensity, as has already been mentioned. This is bad for both the coastal ecosystems, which are some of the most productive in the world and the people who live there, who make up a big part of the world's population.

In demographic terms, the UN estimates that more than 600 million people, or about 10% of the world's population, live in coastal zones that are 10 meters above sea level or lower. This figure rises to 40% if all those living within 100 km of the coastline are included.

Also, with exceptions, the most populated cities, and even the most densely populated ones, are located on the coastal strip, making them vulnerable to the effects of CC. Tourism, fishing, and the oil industry, among others, depending on the resources of this zone. It is not surprising, then, that efforts have been made to evaluate the area's vulnerability to come up with things that can help prevent disasters.

Among other studies, the works published at the end of the last century by Gornitz (1991), Haq and Milliman (1996), and Klein and Nicholls (1999), who, with a global vision, initially focused on sea level rise as the main threat, highlighting the risks that this phenomenon could generate, such as the salinization of low-lying agricultural lands, deterioration in the deltas of the main rivers, damage to coastal wetlands, and coral islands as the ecosystems most susceptible to damage, stand out.

They also point out the dangers of episodic flooding, coastal erosion, and salinization of estuaries and coastal aquifers, which could eventually contaminate freshwater supplies and affect agricultural production. To deal with these problems, they suggest risk assessment and integrated coastal zone management, which would work better if they were done on a regional scale.

As a result of these and other proposals related to the evaluation of coastal vulnerability, Feenstra et al. (1998) were among the first authors to generate a compendium of methods for assessing the impact of CC and to propose various adaptation strategies, including a specific section for the coastal zone in which various management scenarios are proposed (Klein and Nicholls 1998). The latter authors categorize possible impacts as the direct loss of economic, ecological, cultural, and livelihood values.

In their analysis, they highlight vulnerability as a multi-dimensional concept and distinguish between natural vulnerability and socioeconomic vulnerability, which are closely associated, emphasizing that prior knowledge of the possible effects on the natural system is required to determine the extent of these effects on the socioeconomic system. This method has been widely accepted for assessing vulnerability, and it is still used, with some changes, to look at environmental and socioeconomic factors that affect how vulnerable a place is.

Following this approach, the United Nations Environment Programme (UNEP) generated an initiative to evaluate vulnerability indices in coastal zones based on the selection of environmental and socio-economic criteria and indicators, which has been taken up and adapted for application in other latitudes, including the Mexican Pacific Northwest.

Extreme weather events

Extreme events are rare by definition, being established in a practical way as those that are located below or above a certain threshold with a variation of 10% of the distribution of occurrence records at a local level over a relatively long period. Consequently, droughts and storms are considered extreme events within the precipitation spectrum.

However, the significance of these events has resulted in diverse analyses to define the term without reaching a consensus, even when considering their influence to achieve a transdisciplinary understanding useful for the management of such events, which are gaining importance due to their potential to cause damage and impacts to populations, infrastructure, and the environment.

Heat waves, droughts, tsunamis, earthquakes, floods, hailstorms, and severe storms are all extreme events, but only those driven by climate change are possibly increasing in frequency and intensity. Montijo and Ruiz-Luna (2018) point out that there isn't a single definition for "extreme precipitation events" (EPEs). They suggest that EPEs are precipitation events whose volume is above the 90th percentile (P90) of accumulated records and that, because of how strong or long they last, they have the potential to change a region's physical features in a big way.

These types of phenomena are probably increasing in frequency, particularly in the northern hemisphere, which will increase risks, possibly resulting in the loss of lives and resources. Also, it is thought that, unlike the rise in global temperature, which is more or less uniform, the patterns of rainfall will be more complicated and harder to predict.

Especially in the northwest of Mexico, where the so-called "North American Monsoon" or "Mexican Monsoon" is strongest, extreme rain events are likely to happen more often. This is because there have been more records of these events from 1950 to the start of this century.

It is noted that one of the main challenges worldwide in the short and medium term lies in the capacity for adaptation and resilience of communities to the impact of disasters caused by natural phenomena. But everyone agrees that there aren't enough long-term data series with enough quality and detail to make reliable analyses and, thus, better forecasts.

Therefore, the adaptive capacity and resilience to the presence of these phenomena cannot be evaluated in a standard way and with rigid schemes, since there are no immediate possibilities of generating predictions on their severity and impact. In addition to the loss of lives, the impacts generated by EPEs produce income losses by affecting sources of work, with total or partial loss of personal belongings and damage to basic infrastructure; the greatest burden of recovery falls on public finances, with a notable imbalance in Mexico between the funds allocated to prevention and those generated for disaster recovery.

Due to all of this, it is very important to warn coastal communities, which are thought to be more vulnerable, about the possibility of more SPEs and how they might affect their businesses.

Integral vision

As mentioned above, EPEs can eventually lead to floods, landslides, and other negative impacts, also affecting biodiversity and ecosystems, thereby altering the transfer of ecosystem services (Jentsch and Beierkuhnlein 2008) and impacting human health and safety. Because of this, it is important to support an adaptation process that takes local conditions into account and is based on solid scientific data and the strengthening of local institutional arrangements, such as government policies and tools that aim to make people's lives better.

Any technical contribution in this sense contributes to the strengthening of response capacity and favors adaptation processes, particularly in the context of climate change. With this in mind, CONACYT's (No. ref. 2017-01-4764) funding of the project "Determinants of vulnerability and diagnosis of institutional capacity to respond to extreme precipitation events: implications for adaptation in the coastal zone of northwest Mexico" help the country become more resilient to natural disasters and strengthen mechanisms for adapting to climate change, especially in the coastal zone of northwest Mexico.

The goal is to not only contribute to the methodological development of vulnerability assessment in the face of specific meteorological events but also to support the development of institutional capacities with a transdisciplinary approach, given the nature of the phenomenon, to help understand the causes of vulnerability and stop the risks that come with it.

As has already been said, the study area is the coastal zone of northwest Mexico, where environmental and socioeconomic conditions vary. Because the ability to deal with possible impacts depends on these differences, it is important to have tools that can measure vulnerability and its causes in line with the strategies and action lines of the Special Program on Climate Change (2014–2018).

Based on a previous study developed in different regions of Latin America, the approach used here was applied at the municipal scale, depending on the availability of data from different environmental and socioeconomic indicators. The goal is to figure out how vulnerable this area is while also looking at its institutional capacity. This is defined as the variety of tools that the government and society have at their disposal that will help them face and solve a problem that affects everyone.

It is assumed that all municipalities in the country have the same legal and administrative framework, which gives coastal communities a certain ability to respond to EPE. However, this ability can be weakened or strengthened depending on exposure to hazards and threats, as well as the strength of local institutional and citizen arrangements (governance). As much as possible, this local scale is added to the analysis to round it out.

It is also based on the idea that each of the components of this scheme can be dimensionalized through indicators, which will allow the standardization of knowledge throughout the study area and can be extended to other geographical scales, allowing the prioritization of the problem and the prioritization of actions. By including and analyzing institutional capacity components, it will be possible to get information from the local to the regional level that can be used for making decisions and coming up with public policy, which will make the process of adapting easier.

Considering that an ecosystemic approach must be taken, which integrates society with its environment, the analysis of changes in the extent of some land covers and uses, especially those related to wetlands, has been added as an approximation to the trends of change in the ES that these environments generate and that serve as indicators of resilience capacity. This is a new topic that has just been added to the discussion.

So, combining the above-mentioned methodological approaches will make it possible to see the problem of vulnerability to EPE with a transdisciplinary approach and a broader view. This is because it is based on the idea that including different scales of analysis (local, municipal, state, and regional) will make it easier for local governments that want to deal with the problem to choose which issues to prioritize and possibly solve.

By Arturo Ruiz-Luna, Aimée Cervantes-Escobar, Rafael Hernández-Guzmán, Abril Montijo-Galindo. Source: CIAD. The link is included below for those interested in downloading the book in digital format: https://drive.google.com/file/d/1_LgmyJiBiZmj5CnhavE6iin_LSkgMCJ8/view?usp=sharing