Concerns and emotions related to climate change and students’ mental health before and after the floods in Rio Grande do Sul, Brazil

Preocupação e emoções com as mudanças climáticas e saúde mental de estudantes antes e depois das enchentes no Rio Grande do Sul, Brasil

Preocupaciones y emociones relacionadas con el cambio climático y la salud mental de los estudiantes antes y después de las inundaciones en Río Grande del Sur, Brasil

Abstract

This study aimed to assess the association between concern and negative emotions about climate change and mental health among students in Rio Grande, Rio Grande do Sul, Brazil, before and after the 2024 flood. A quantitative, single-group pre-post design was used. The outcomes were concerned about climate change and negative emotions or thoughts that harmful events may occur due to climate change (yes/no). Mental health was assessed using the Depression, Anxiety, and Stress Scale for Adolescents. Adjusted linear regression analyses were performed, with results expressed as beta coefficients and 95%CIs. Increases were observed from pre- to post-event in concern, negative emotions, depression, anxiety, and stress. Depression scores increased significantly among those concerned about climate change before and after the flood, and depression and anxiety scores rose among those with negative emotions. Students showed increased climate-related concern and emotional distress, along with worsened mental health, following the extreme event.

Key words:
Flood; Posttraumatic stress disorder; Ecoanxiety; Extreme weather events; Adolescent

Resumo

O estudo teve como objetivo avaliar a associação entre preocupação e emoções negativas relacionadas às mudanças climáticas e à saúde mental de estudantes de Rio Grande, Rio Grande do Sul, Brasil, antes e após a enchente de 2024. Trata-se de um estudo quantitativo com delineamento pré e pós-teste em um único grupo. Os desfechos foram a preocupação com as mudanças climáticas e emoções negativas ou pensamentos de que eventos prejudiciais podem ocorrer devido às mudanças climáticas (sim/não). A saúde mental foi avaliada pela Escala de Depressão, Ansiedade e Estresse para Adolescentes. Foram feitas análises de regressão linear, com resultados expressos em coeficientes beta e IC95%. Observou-se aumento de preocupação, emoções negativas, sintomas de depressão, ansiedade e estresse no período pós-evento. Os escores de depressão aumentaram significativamente entre os preocupados antes e depois da enchente, assim como os escores de depressão e ansiedade entre os que relataram emoções negativas. Conclui-se que os estudantes apresentaram maior preocupação e sofrimento emocional relacionados ao clima, além de piora da saúde mental após o evento extremo.

Palavras-chave:
Enchente; Transtorno de estresse pós-traumático; Ecoansiedade; Eventos climáticos extremos; Adolescente

Resumen

Este estudio tuvo como objetivo evaluar la asociación entre la preocupación y las emociones negativas relacionadas con el cambio climático y la salud mental de estudiantes en Rio Grande, Rio Grande do Sul, Brasil, antes y después de la inundación ocurrida en 2024. Se utilizó un diseño cuantitativo de grupo único con evaluación pre y postevento. Las variables de resultado fueron la preocupación por el cambio climático y la presencia de emociones o pensamientos negativos ante la posibilidad de eventos dañinos causados por el cambio climático (sí/no). La salud mental se evaluó mediante la Escala de Depresión, Ansiedad y Estrés para Adolescentes. Se realizaron análisis de regresión lineal ajustados, con resultados expresados en coeficientes beta y sus respectivos intervalos de confianza (IC) del 95%. Se observaron aumentos significativos del pre al postevento en preocupación, emociones negativas, depresión, ansiedad y estrés. Los puntajes de depresión aumentaron significativamente entre quienes estaban preocupados por el cambio climático antes y después de la inundación, y los puntajes de depresión y ansiedad se incrementaron entre quienes presentaban emociones negativas. Se concluye que los estudiantes presentaron un aumento en la preocupación y el malestar emocional con relación al clima, además de empeorar su salud mental tras el evento extremo.

Palabras clave:
Inundación; Trastorno de estrés postraumático; Ecoansiedad; Eventos climáticos extremos; Adolescente

Introduction

Human activities, especially greenhouse gas emissions, have caused global warming, which has, in turn, accelerated climate change worldwide¹. In addition to directly contributing to humanitarian health emergencies triggered by extreme events such as heatwaves, wildfires, tropical cyclones, hurricanes, and floods², these climate changes have become increasingly frequent and intense across the globe, posing a serious threat to human health².

As an example of this, at least 14 extreme events were experienced in the state of Rio Grande do Sul, Brazil, in less than a year, such as the passage of cyclones and significant floods³, the last of which occurred between late April and early May 2024 and was the largest among them, with record rainfall volumes and unprecedented floods⁴, as a consequence of the El-Niño⁵.

This flood led to a state of public calamity. Essential services were interrupted and there was speculation regarding basic survival items. In one of the most affected municipalities, around 2,000 people were in a situation of environmental refugees until May 6, 2024⁶. Events of this magnitude have generated fear in the population and increased several health problems, including mental and psychological health issues treated in the literature as ecoanxiety^7,8.

Ecoanxiety was initially described by Albrecht et al.⁹ and adopted by the American Psychology Association¹⁰ as a chronic fear of suffering an environmental cataclysm, which occurs when observing the impact of apparently irrevocable extreme events, generating a concern associated with the future of oneself and the next generations. Moreover, this problem can cause chronic fear of environmental catastrophe, a mix of negative emotions such as concern and sadness¹¹.

A recent systematic review has shown that younger generations, women, and more impoverished countries in the global south are more affected by mental health problems from concerns about climate change¹². A study conducted with young people from several countries around the world, including Brazil, found that 59% of participants were very much or extremely concerned about climate change, and more than 50% reported sadness, anxiety, irritation, and helplessness before such changes, besides feeling helpless and guilty¹³. Additionally, around 45% also reported that climate change negatively affected their daily lives, besides having negative thoughts about climate change, reporting that they think the future is scary¹³.

Regarding Brazilian children and adolescents, a qualitative study by Chou et al.¹⁴ showed that children and adolescents with a profile that was aware of and engaged with climate change were those who most perceived climate change as imminent and as needing self-protection, the need to act urgently for what is not yet lost, negative emotions, and feeling pressured to act in some way vis-à-vis such changes.

The evidence described above highlights the importance of verifying the effects of exposure to extreme events, such as the floods experienced in Rio Grande do Sul, on the mental health of children and adolescents. However, studies with Brazilian adolescents that assess ecoanxiety and its possible acute impacts on the manifestation of mental health symptoms after an extreme climate event are scarce. Therefore, this study aims to verify the changes in concerns and negative emotions about climate change and in depression, anxiety, and stress symptoms in students from a municipality in the extreme south of Rio Grande do Sul after the floods that occurred between late April and early May 2024 in Rio Grande do Sul, Brazil. Additionally, we analyzed whether the concern about climate change and the negative emotions related to it impacted the possible changes in the mental health symptoms of these students, using the same research instruments at both points of data collection.

Methods

Rio Grande has 191,900 inhabitants and is 313 kilometers away from the capital of Rio Grande do Sul (Porto Alegre)¹⁵. The municipality is peninsular, bathed by Lagoa dos Patos and the Atlantic Ocean. The flood that occurred in Rio Grande between late April and early May was caused by heavy rainfall and Lake Guaíba’s water runoff, which bathes Porto Alegre, to Lagoa dos Patos, which bathes several municipalities in the state, including Rio Grande, where it reached significantly high levels, flooding most of the city, such as the riverside regions, which involve a significant part of the municipality’s territory due to its peninsula characteristics. The public state school involved in the study is in the Cassino neighborhood, a beach resort that was not directly affected by the flood but has the Barra jetties channel nearby. In this place, the waters of the lagoon drain into the ocean. Figure 1 presents a map of the municipality of Rio Grande, RS, highlighting its peninsular characteristics. The map also indicates the location of the Cassino neighborhood, where the school involved in the study is located¹⁶.

Figure 1
Map of the municipality of Rio Grande, RS, highlighting its peninsular characteristics and the location of the Cassino neighborhood, where the school involved in the study is located¹⁶.

Study design

This quantitative, analytical study was conducted using before-and-after measurements on a single group, with the same research instruments employed at both data collection points (Chart 1). It is nested in a longitudinal project that started collecting data with adolescents from 10 public state schools in Rio Grande do Sul in April 2024, which was interrupted the following month due to the weather conditions and floods that affected the state. Data collection resumed after suspended classes, making it possible to evaluate the same group of students at different times.

Chart 1
Questionnaire used in the study.

Questions and answer options from the instruments used at both data collection points. DEMOGRAPHIC DATA 1) Full name: _____________________________________________________ 2) Gender: □ Male □ Female 3) Age: _________________ (complete years) 4) What is your race or ethnicity? □ White □ Black □ Asian □ Brown □ Indigenous 5) What grade are you currently in? □ 7th □ 8th □ 9th □ 10th □ 11th □ 12th CLIMATE CHANGE 1) Do you worry about climate change? □ No □ Yes 2) Have you independently found interesting information about climate on the internet or social media? □ No □ Yes 3) Have you experienced negative emotions regarding climate change, or had thoughts and feelings that harmful events could happen to the planet because of climate change? □ No □ Yes DEPRESSION, ANXIETY, AND STRESS SCALE FOR ADOLESCENTS 1) I had difficulty calming down. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 2) I noticed that my mouth was dry. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 3) I was unable to feel positive emotions. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 4) I had difficulty breathing (for example, I breathed very rapidly or experienced shortness of breath without physical exertion). □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 5) It was hard to take initiative to do things. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 6) In general, I had exaggerated reactions to situations. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 7) I had tremors (for example, in my hands). □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 8) I felt very nervous. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 9) I was worried about situations in which I might panic and embarrass myself. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 10) I felt I had no positive expectations about anything. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 11) I noticed that I was getting restless. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 12) I found it difficult to relax. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 13) I felt down and sad. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 14) I had no patience with things that interrupted what I was doing. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 15) I felt I was about to panic. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 16) I couldn’t get excited about anything. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 17) I felt I had little value as a person. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 18) I felt that I was very irritated. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 19) I noticed my heart beating faster without physical exertion (for example, the sensation of an increased heartbeat or an irregular heartbeat). □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 20) I felt scared without reason. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week 21) I felt that life had no meaning. □ It did not happen to me this week □ It happened a few times this week □ It happened most of the week □ It happened almost all the time this week Questions used only in the second data collection phase FLOOD IMPACT 1) Were you and the people who live with you directly affected by the flood (did water enter the house, or did you lose property due to the floods)? □ No □ Yes 2) Were any relatives who do not live with you, or friends affected by the flood (water entered their house or they lost property due to the floods)? □ No □ Yes

• Source: Authors.

Population and sample

The sample included all students who participated in at least one phase of data collection, representing both genders and enrolled in the final years of elementary school. All students regularly attended classes at one of the ten selected public schools in the city’s urban area as part of the longitudinal study. In the first stage, the total sample consisted of 45 adolescents. During the second stage, only two students lost to follow-up (n = 43) due to their absences from classes over a two-week period of active searching at the school (Table 1).

Table 1
Sample characteristics across the two data collection phases.

Variables	Total sample before (45)		Total sample after (43)
	N	%	N	%
Gender (female)	24	53.7	24	55.8
Age (years)
12	5	11.4	5	11.9
13	14	31.8	10	23.8
14	17	38.6	14	33.3
15	4	9.1	9	21.5
16	4	9.1	4	9.5
Skin color
White	24	55.8	23	57.2
Black/brown	17	39.5	16	38.1
Yellow	2	4.7	2	4.7
School grade (high school)
7º	11	24.4	10	23.3
8º	16	35.6	15	34.9
9º	18	40.0	18	41.8
Economic status
A (higer socioeconomic status)	8	22.2	8	23.5
B	19	52.8	18	53.0
C (lower socioeconomic status)	9	25.0	8	23.5
Affected by the floods (yes) (n = 42)	-	-	26	61.9

• Source: Authors.

Ethical aspects

The Federal University of Rio Grande Research Ethics Committee approved the study, which was registered under Protocol No. 6.703.297, CAAE:77513224.5.0000.5324. All participants presented an Informed Consent Form signed by a legal guardian and agreed to participate through the Informed Assent Form.

Inclusion and exclusion criteria

The study included students regularly enrolled in the selected school aged 12-16. Students with some cognitive impairment or who did not answer questions questionnaire involving the variables of this study were excluded.

Data collection

The first data collection occurred in April 2024 (April 22-26), before the floods in the state and municipality. Data collection resumed after the period of suspended classes, and the same participants were again sought to respond to the research instruments in June and July of the same year (June 24-July 3). A team of trained researchers conducted the collection, and the data were collected through tablets using the Research Electronic Data Capture (RedCap) platform, with the responses self-reported by the participants.

Study variables

Demographic and economic variables were collected from self-reported information on gender (male, female), age (in years), skin color or ethnicity (White, Black, Yellow, Brown, or Indigenous), and socioeconomic stratum measured from the questionnaire of the Brazilian Association of Research Companies (ABEP)¹⁷, where students were identified as being from strata A (higher socioeconomic status), B (including strata B1 and B2) and C (lower socioeconomic status; including strata C1 and C2).

Concern about climate change was assessed through a question adapted from a study by Chou et al.¹⁴, in which students were asked the following question: “Are you concerned about climate change?” with a dichotomous answer (yes or no) as the response option. Those who responded positively to the question were deemed to be concerned. Furthermore, students were asked whether they had negative emotions regarding climate change or thoughts and feelings that bad things could happen to the planet because of climate change, and whether they found interesting information about the climate on their own on the internet, social networks¹⁴, also with a dichotomous answer (yes or no). Regarding these questions and according to the students’ responses at both times, a categorical variable was created in which they were distributed into four groups: No-No (negative responses at both times); no-yes (positive response only at the second time); yes-no (positive response only at the first time) and yes-yes (positive responses at both times).

Anxiety, depression, and stress symptoms, and the overall mental health score, were measured using the Depression, Anxiety, and Stress Scale for Adolescents in its short form (DASS-21), validated and adapted, for Brazilian adolescents¹⁸. Each of the 21 items on the scale has response options on a Likert scale ranging from 0 (no symptoms) to 3 (worst symptoms), and the score is generated by adding the questions together and multiplying by 2. The higher the score, the worse the mental health problems. Cronbach’s alpha for the scale was 0.91 before the flood and 0.95 for the post-flood period.

To assess whether students were affected by the flood in the municipality, two new specific questions were included in the second phase of the survey, namely: “Were you and the people who live with you directly affected by the flood (did water enter the house or did you lose property due to the floods)?; and, “Were any relatives who do not live with you or friends affected by the flood (water entered their house or they lost property due to the floods)?” Both questions had a dichotomous answer option (yes or no).

Statistical analysis

Data from the RedCap platform were exported to the Stata statistical package (version 14.2), where statistical analyses were conducted. Descriptive results are shown as means and standard deviations for continuous variables and absolute and relative frequencies for categorical variables. Comparisons between measurements before and after the floods were performed using the McNemar test for categorical variables and the paired t-test for continuous variables.

Changes and factors associated with mental health symptoms (depression, anxiety, stress, and total DASS-21 score) were assessed using random-effect linear regressions. For each outcome analyzed, the time variable (pre-post), gender, and the variables of concern and negative emotions about climate change, as well as having been impacted by floods, were included as possible predictors. Interaction terms between time and the other variables in the model were created to identify possible moderations of these variables in the changes in mental health symptom scores before and after the extreme climate event. Additionally, a new linear regression models with random effects were performed to test the interactions between time and perceived concern about climate change and negative emotions about climate change before and after the extreme climate event. Regression coefficients (b) with 95% confidence intervals (95%CI) were used as effect measures. Standard errors and 95%CI of the regression coefficients were obtained using the bootstrap resampling method with one thousand random samples and a 4-digit random seed (1234). The significance level adopted in this study was p < 0.05 for two-tailed tests for all analyses performed.

Results

The study achieved a response rate of 95.5%. During the initial data collection, 45 students were evaluated, with the majority being female (53.7%) and white (55.8%), and their ages ranging from 12 to 16 years. Most students were in ninth grade (40%), and 52.8% belonged to socioeconomic B (middle), characteristics that largely remained unchanged during the second data collection (Table 1).

In the second phase, two students were lost to follow-up: one aged 13 and another aged 14, both from the seventh and eighth grades, respectively, one identified as white and the other as brown, and both residing in the municipality’s urban area. Overall, 61.9% of the students reported being directly or indirectly affected by the floods, while 83.7% stated that they found climate-related information engaging on the internet and social media.

Figure 1 shows the percentage of students who reported concerns and negative emotions about climate change (Figure 2A) and the mean score of mental health symptoms (Figure 2B) before and after the extreme weather event. There was a significant increase in the percentage of students who were concerned about climate change (35.6% vs. 67.4%) and the percentage of students who reported having negative emotions about climate change or thinking and feeling that bad things could happen to the planet because of climate change (44.4% vs. 69.8%). Regarding mental health variables (Figure 2B), the bivariate analysis identified an increase in depression, anxiety, and stress scores and, consequently, in the overall DASS-21 scores.

Figure 2
Perceptions about climate change (A) and mental health symptoms (B) before and after the extreme climate event.

Table 2 presents the changes and factors associated with mental health symptom scores after the extreme weather event. A significant increase was observed in the scores of depression (β = 2.68, 95%CI = 0.76; 4.60, p = 0.006), anxiety (β = 2.85, 95%CI = 0.83; 4.88, p = 0.006), and stress (β = 2.51, 95%CI = 0.48; 4.54, p = 0.015) symptoms, and in the overall DASS-21 score (β = 4.19, 95%CI = 1.53; 6.85, p = 0.002).

Table 2
Changes and factors associated with mental health symptoms after an extreme climate event.

	Depressive symptoms		Anxiety		Stress		DASS-21 Overall score
	B (95%CI)	P	B (95%CI)	P	b (95%CI)	p	b (95%CI)	p
Time	2.68 (0.76; 4.60)	0.006	2.85 (0.83; 4.88)	0.006	2.51 (0.48; 4.54)	0.015	4.19 (1.53; 6.85)	0.002
Gender (Female)	4.10 (0.27; 7.92)	0.036	6.54 (1.94; 11.13)	0.005	7.11 (2.19; 12.04)	0.005	8.89 (2.60; 15.17)	0.006
Concerns about climate change (yes)	-2.20 (-4.91; 0.51)	0.112	-2.33 (-5.31; 0.64)	0.125	-0.06 (-3.29; 3.17)	0.971	-2.68 (-6.60;1.23)	0.180
Negative feelings about climate change (yes)	1.80 (-0.69; 4.29)	0.156	1.04 (-1.64; 3.72)	0.447	1.12 (-1.35; 3.60)	0.373	1.77 (-1.48; 5.02)	0.285
Being impacted by the floods (yes)	1.91 (-1.87; 5.68)	0.322	2.74 (-1.35; 6.83)	0.190	3.64 (-1.03; 8.31)	0.127	4.11 (-1.72; 9.94)	0.167
Interactions	B (95%CI)	P (interaction)	B (95%CI)	P (interaction)	b (95%CI)	P (interaction)	b (95%CI)	P (interaction)
Time vs. Gender
Male	1.48 (0-.53; 3.49)	0.116	0.82 (-1.64; 3.30)	0.006	0.44 (-1.91; 2.70)	0.008	1.61 (-1.39; 4.61)	0.015
Female	3.63 (1.01; 6.25)		4.52 (2.00; 7.04)		4.20 (1.55; 6.84)		6.29 (2.74; 9.83)
Time vs. Concerns about climate change
No	3.15 (0.38; 5.91)	0.274	3.29 (0.65; 5.92)	0.289	2.24 (-0.15; 4.63)	0.772	4.62 (1.11;8.12)	0.369
Yes	2.03 (0.03; 4.03)		2.18 (0.13; 4.21)		2.52 (0.60; 4.44)		3.42 (0.79; 6.04)
Time vs. Negative feelings about climate change
No	1.57 (-0.48; 3.62)	0.068	2.01 (-0.24; 4.26)	0.181	1.74 (-0.41; 3.87)	0.151	2.89 (0.11; 5.67)	0.089
Yes	3.22 (1.13; 5.32)		3.20 (1.15; 5.25)		2.86 (0.80; 4.92)		4.76 (2.06; 7.45)
Time vs. Affected by the floods
No	1.71 (-0.17; 3.60)	0.170	1.77 (-0.39; 3.93)	0.176	1.06 (-1.18; 3.31)	0.067	2.42 (-0.21; 5.05)	0.094
Yes	3.30 (0.87; 5.72)		3.53 (0.99; 6.06)		3.41 (0.91; 5.91)		5.31 (1.83; 8.78)

• Source: Authors.

Female students had on average, higher scores than males in all mental health symptoms analyzed, with regression coefficients ranging from 4.10 (95%CI = 0.27; 7.92, p = 0.036) for depressive symptoms to 8.89 (95%CI = 2.60; 15.17, p = 0.006) for the total DASS-21 score. Interaction analyses showed that the increase in symptoms of anxiety, stress, and overall DASS-21 scores after the extreme weather event occurred more markedly in female students.

Figure 3 (A to D) shows the changes in mental health symptoms per perceived concern about climate change before and after the extreme weather event. For all conditions evaluated, students with concerns before and after the event (yes-yes) had significant symptom elevations. However, significant interactions were seen only for depressive symptoms between the yes-yes group (β = 4.64, 95%CI = 1.91; 7.38) and the no-yes (β = 0.81, 95%CI = -1.33; 2.95, p-interaction = 0.006) and yes-no (β = -0.12, 95%CI = -3.72; 3.47, p-interaction = 0.031) groups.

Figure 3
Interaction between time (before and after) and concerns about climate change in mental health symptoms.

Figure 4 (A to D) shows the changes in mental health symptoms per the occurrence of negative emotions resulting from climate change before and after the extreme climate event. For all symptoms assessed, students with negative emotions before and after the event (yes-yes) and only after the event (no-yes) showed significant increases in scores. However, significant interactions were seen for depressive symptoms between the yes-yes group (β = 5.11, 95%CI = 1.59; 8.62) and the no-no group (β = 0.76, 95%CI = -1.96; 3.48, p-interaction = 0.015), for anxiety symptoms between the yes-yes group (β = 4.43, 95%CI = 1.28; 7.78) and the no-no group (β = 0.75, 95%CI = -1.59; 3.10, p-interaction = 0.028) and overall DASS-21 scores between the yes-yes group (β = 6.76, 95%CI = 2.12; 11.40) and the no-no group (β = 1.37, 95%CI = -1.63; 4.38, p-interaction = 0.022).

Figure 4
Interaction between time (before and after) and negative feelings about climate change mental health symptoms.

Discussion

The results indicate a significant increase in concern about climate change, along with negative emotions and thoughts related to the potential harmful impacts on the planet due to these changes. Symptoms of anxiety, depression, and stress were also noted, along with a decline in overall mental health indicators, particularly among girls. The study revealed an increase in depressive symptoms among students who were already concerned about climate change before the flood and remained concerned afterward, as well as among those who initially did not express concern but became worried after the extreme event. Furthermore, there was a significant rise in symptoms of depression, anxiety, and overall mental health issues among those who reported negative emotions regarding climate change, both before and after the floods.

Floods are the most frequent natural disaster, with approximately 23% of the global population exposed to them¹. Projections indicate an escalation in the severity, duration, and frequency of floods due to increasingly frequent extreme precipitation events and rising sea levels caused by global warming, which is responsible for climate change¹.

The increased concern and negative emotions related to climate change observed in this study reflect global patterns, where a large percentage of young people, including those older than the sample studied (16-25 years), demonstrate extreme concern about climate change¹³. Many have reported negative impacts of these changes on their daily lives and express pessimistic thoughts about the planet’s future¹³. In Brazil, 29% of young people reported being very concerned, and 38% reported being extremely concerned about climate change change¹³.

Some of the impacts of extreme climate events have harmful consequences for the mental health of affected individuals^13,21, and even children and adolescents with little awareness of climate threats may develop a fear of nature and the natural risks that can emerge following such events¹⁴. In this context, it is essential to understand the how these climate change perceptions might impact their mental health to develop effective communication strategies, promote climate education, and help them cope with their anxiety and distress related to climate change¹⁴.

The elevated symptoms of depression and anxiety among students concerned about climate change, as well as among those with negative emotions and thoughts about it before and after the extreme climate event, reflect what is highlighted in the literature: the greater the concern and negative feelings young people have about such events, the higher the prevalence of these symptoms and other mental disorders^13,21. In Tanzania, young people aged 18 to 23 who were most affected by climate change exhibited more symptoms of depression²¹, and those who expressed greater concern about these changes also had more general mental health problems²¹.

Regarding the fact that girls showed the greatest increase in mental health problems, this situation reflects the Brazilian context, where girls are more affected by common mental disorders²² and, at the same time, show greater psychological distress resulting from concern about climate change^12,21. Most students (about 60%) were indirectly affected by the flood, yet the mental health issues were alarming. The effects could have been even more severe if they had been directly affected. A qualitative study conducted in Bangladesh with 53 adolescents living in shelters for flood victims demonstrated high prevalence rates of post-traumatic stress and depression, especially among girls, who showed prevalence rates above 80% for these disorders²³.

Current epidemiological data on the health impacts of floods have focused on the risks of hospitalization, the incidence of digestive and infectious diseases, and mental disorders²⁰, corroborating these findings. In Brazil, specifically in Rio Grande do Sul, studies based on data from the general population affected by the same 2024 flood highlighted in the present study focused on outcomes such as leptospirosis²⁴ and dermatitis²⁵, identifying increased incidence of these diseases due to this climate catastrophe.

Different types of extreme climate events can cause and intensify symptoms leading to negative emotions^26-29, such as sadness and guilt²⁶, depression, anger, violence²⁷, anxiety disorders and post-traumatic stress²⁹, in addition to negatively affecting well-being and quality of life³⁰. These mental health problems observed after disasters result in various immediate adverse consequences for psychological well-being¹⁰. However, classic studies in the field, related to the psychiatric implications of direct experiences of emergencies and disasters, indicate increasing stress levels during the first year following the event, depending on the type of exposure the victim experienced^22,31. Based on the findings of the present study, one may hypothesize that, due to the relationship between mental health issues, particularly symptoms of depression and post-traumatic stress disorder³², the majority of the effects of the extreme event on students’ mental health may be associated with this type of disorder.

The neighborhood where the school involved in the study is located was not directly affected by the flood, and the flooding in the city may not be the direct cause of the reported increase in concern about climate change, related negative emotions and thoughts, or the rise in mental health problems. However, it is plausible to argue that information from social media may have intensified climate-related perceptions and tensions, as it is assumed that students closely followed the events in Rio Grande do Sul. More than 80% reported seeking information on the topic via the internet and social media. This may have increased uncertainty regarding future events in the municipality of Rio Grande, where the water began to rise and flooded the city nearly a week after other regions of the state. Thus, this uncertainty may also have negatively affected students’ mental health, emotions, and concerns about climate change and eco-anxiety.

Although a large portion of young people sought climate-related information online and on social media, the access to reliable and high-quality information can be complex depending on the type of humanitarian crisis and the post-event context. This is particularly relevant given the spread of fake news, which has been intensified by the easy access to artificial intelligence and popularized in scientific discussions during the COVID-19 pandemic^33-35. Although one study indicates that most individuals consume news neutrally³⁶, other studies show that this exposure may be associated with symptoms of post-traumatic stress in more vulnerable or younger populations, especially when fake news is consumed^37-40.

This study had some limitations that may have affected the interpretation of the results, such as the study design, which showed weaknesses in terms of internal and external validity, and the small sample size, which reduced the statistical power of the analysis. Furthermore, the fact that the school’s neighborhood was not directly affected by the flood may have reduced the prevalence of some outcomes, especially mental health outcomes, which could also have been underestimated due to their longer manifestation period, as flood-related exposures can persist for up to 210 days after the event²⁰.

Nevertheless, this is one of the few studies conducted in the country addressing this topic. Considering the timing of data collection, it allowed for an almost real-time assessment of the extreme event’s impact on students, as the initial data collection took place in the week before the start of the floods. Data collection was interrupted due to school closures in response to the state of public emergency and returned almost simultaneously with the return of water levels to normal, as the water drained into the ocean. The importance of future longitudinal studies and more robust methodological designs is highlighted to deepen the understanding of the relationship between concern and emotions about climate change and mental health problems.

The findings indicated, almost in real time, a significant increase in students’ concern about climate change, along with negative emotions and thoughts on the topic. A worsening of mental health problems was also evidenced from the beginning to the end of the floods in Rio Grande do Sul and in the city of Rio Grande, particularly among girls. The fact that students showed a substantial increase in depressive symptoms and general mental health indicators contributed to the rise in climate concern as well as in negative emotions and thoughts related to climate change. This effect was more pronounced among those who were already concerned before the extreme event and remained so, or among those who were previously unconcerned but became worried after the event. These findings point to an acute increase in mental health problems among the evaluated students. Consequently, there was an increase in concern about climate change and related negative emotions, underscoring the importance of public health actions, including those within the school environment, in preparing and supporting young people in the face of these increasingly frequent climate conditions.

Acknowledgments

The authors acknowledge the expertise of Raquel de Carvalho Dumith and appreciate her technical support in creating the map artwork of the municipality of Rio Grande, RS.

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Funding

CNPq/MCTI Call No. 10/2023 - Track A - Emerging Groups - 421455/2023-3.

Data availability statement

The data sources adopted in the research are indicated in the article’s body.

Chief editors:

Maria Cecília de Souza Minayo, Romeu Gomes, Antônio Augusto Moura da Silva, Vania de Matos Fonseca

Publication Dates

• Publication in this collection
  09 Oct 2026
• Date of issue
  2026

History

• Received
  16 Sept 2024
• Accepted
  06 Aug 2025
• Published
  08 Aug 2025