Mental health and wellbeing outcomes of climate change mitigation and adaptation strategies: a systematic review

Climate change has already impacted the health and wellbeing of ∼5 billion people globally. However, the potential influence of climate change mitigation and adaptation strategies on mental health and wellbeing outcomes in low-and-middle-income countries (LMICs) remains insufficiently understood. We aimed to determine the effect of these strategies on mental health and wellbeing outcomes among LMIC beneficiaries. We carried out a systematic review to identify intervention and case studies published from 2013 to 2022, searching OVID Medline, Embase, PsycINFO, Global Health, Cochrane Library, GreenFile, Web of Science, and a subset of studies from the ‘Global Adaptation Mapping Initiative’ database. We included controlled, quasi-experimental, pilot, and focussed case studies reporting mental health or wellbeing outcomes assessments of climate change mitigation and adaptation strategies. We categorised studies by design, geographic region, target population, setting, environmental hazard, strategy type and primary outcomes. PROSPERO registry: CRD42021262711. A total of 9532 studies were initially retrieved, and 15 studies involving 12 255 participants met the inclusion criteria. Among these, twelve studies described evidence from single-adaptation strategies in nine LMICs, while three reported mitigation programmes. Only two randomised evaluations assessed common mental disorders such as depression, trauma or anxiety using validated scales. Most studies evaluated broader wellbeing at the community and individual levels. Nine studies (53.3%) reported significant beneficial changes in mental health or wellbeing outcomes among beneficiaries, while six (46.7%) obtained mixed results linked to local and sociocultural factors. The interventions ‘practical significance and overall impact remained unclear due to the heterogeneous reporting in program effectiveness, gaps in effect size assessments or qualitative insights. Our review highlights the scarcity and limited nature of the current evidence, underscoring the need for further equitable research. The ongoing global climate and mental health crises press us to fully understand and address these strategies’ psychosocial impacts and translate these findings into effective policy and transdisciplinary action as an opportunity to prevent and ameliorate significant, long-term problems in the population’s mental health and wellbeing.


Introduction
The climate change crisis negatively affects human health [1][2][3], particularly mental health and overall wellbeing [4,5].Low-and-middle-income countries (LMICs) are disproportionately vulnerable to these impacts and have the least resources to prepare for [6,7] and recover from them [8].The interconnected consequences include far-reaching, profound impacts [9], such as increased frequency and severity of extreme weather events, sea level rise and coastal erosion, changes in precipitation patterns, food and water insecurity, displacement, and loss of livelihoods [10].Unfortunately, there is a lack of research on the mechanisms and extent of these impacts, including the effects of protective interventions on mental health, particularly in LMICs [7].
Climate change exacerbates the risk factors, mechanisms, and drivers of poor mental health and psychosocial wellbeing at both population and individual levels.The World Health Organization acknowledges that 'Several environmental, social, and economic determinants of mental health are negatively affected by climate change' [11].These effects include increased rates of common mental disorders, decreased social cohesion, and increased violence [12], especially targeting historically marginalised groups [13,14].
On the other hand, climate change mitigation and adaptation responses can positively impact human health and wellbeing [15] by addressing risks [16], promoting resilience, improving global health and benefiting vulnerable populations [17,18].Globally, climate change mitigation strategies such as transitioning to clean energy sources can improve air and water quality, reduce noise pollution, and create new economic opportunities [19].Adaptation strategies [20], such as building resilient infrastructure and early surveillance systems for environmental hazards, can improve safety and reduce the negative impacts of extreme weather events.These strategies have been linked to general health co-benefits [15,21], although their specific impact on mental health and wellbeing outcomes [19], especially in LMICs, remains limited.For example, providing agricultural extension services and financial resources can alleviate stress and anxiety among subsistence farmers [22].Implementing integrated screening programs and participatory community-level activities can decrease depression and domestic violence and increase conflict resolution and community resilience in postflooding settings [23].Successful recovery efforts from flooding events require local knowledge and interdisciplinary collaboration, with careful consideration of unintended consequences associated with psychosocial interventions [24].Urban centres can benefit from adaptation actions such as expanding green spaces, strengthening health systems, and building resilient infrastructure [25].However, these strategies need greater attention and consideration for underserved communities and their potential impact on mental health and wellbeing in LMICs.
Despite the well-established evidence on the negative impact of climate change on mental health and wellbeing, few ongoing efforts to implement mitigation and adaptation strategies incorporate mental health measurements into their evaluation.To effectively address the impacts of climate change, it is crucial to integrate mental health considerations into the design and evaluation of these strategies.
This comprehensive approach allows us to understand the full impact of these strategies and consider the complex interplay between socioeconomic, structural, and political factors that contribute to human vulnerability to climate change effects and extreme weather events [26,27].
Considering mental health and wellbeing as key outcomes that cut across the lifespan in response to climate change can improve mitigation and adaptation planning efforts and ensure effective and equitable results.Such an approach would address the root causes of climate change threats, structural vulnerabilities, and contextual synergies that affect communities with high climatic and environmental exposures.It could provide an argument for a more streamlined, coordinated, and cost-efficient climate action approach across households, researchers, and policymakers.
Despite the reported benefits of these strategies, depending on population groups and geographical contexts they can also be harmful [17] linked to complex social dynamics.For example, programs that relocate at-risk communities can potentially cause distress linked to loss of cultural identity and disruption of social cohesion [28] Particularly if these strategies are not implemented widely across communities or fail to consider unique local aspects, they can lead to local injustices.For instance, a renewable energy-based electrification project in rural communities of Cajamarca, Peru [29] caused community discord when some households were selected for the intervention while others were not.Similarly, projects focusing on livelihood diversification through technology can address environmental shocks and poverty but may also exacerbate income and wellbeing inequities for those facing structural entry barriers [30].
The evidence base regarding the co-benefits of mental health and wellbeing remains limited, highlighting the need for further studies exploring the effects of climate change responses on human health.Existing reviews have addressed specific aspects but have not fully assessed the effects of both mitigation and adaptation strategies on mental health outcomes.For example, a systematic mapping of global research on climate change adaptation interventions and health emphasised the scarcity of evidence in this area [16].A recent systematic review [31] focussed on the conceptual framings of individual and community-level mitigation actions and explored mental health themes but did not specifically assess the effects of mitigation strategies.Another scoping review [32] examined the health impacts of adaptation strategies in informal settlements in LMICs but did not report results on mental health outcomes.Finally, a systematic review on urban green spaces and wellbeing [33] found positive effects on human wellbeing, including health aspects; however, evidence regarding mental health and wellbeing outcomes related to climate change mitigation and adaptation strategies remains scarce.
This review addresses this knowledge gap by compiling and assessing evidence on the co-benefits of climate change mitigation and adaptation interventions for mental health and wellbeing in LMICs by (1) examining the impact of climate change mitigation and adaptation interventions on mental health and wellbeing outcomes in LMICs, (2) reviewing the evidence base of this association, and (3) evaluating the effects of those interventions by type, climatic/environmental risk, and by their impact on different population groups and context.This systematic review is timely given the major impacts of climate events on mental health outcomes in LMICs [7,34] and the increasing implementation of climate change adaptation and mitigation strategies in these settings [35,36].Health and human wellbeing must be central in climate action, and research is critically needed to inform evidencebased policy and practice in this area.

Search strategy and selection criteria
In this systematic review, we defined climate change mitigation activities as those that 'contributes to stabilising greenhouse gas (GHG) concentrations in the atmosphere to prevent anthropogenic interference with the climate system by reducing or limiting GHG emissions or enhancing GHG sequestration'.A climate change adaptation refers to 'activities that reduce the vulnerability of human or natural systems to the impacts of climate change and climate-related risks, and enhance adaptive capacity and resilience' [37].The term 'adaptation' was deliberately not included in the search.Some authors may not have explicitly framed their studies about adaptation but would have incorporated key elements that matched this review's definition and inclusion criteria.Kelly and Adjer [38] define vulnerability as the capacity to 'anticipate, cope with, resist, and recover from a natural hazard' and highlight that reducing vulnerability is essential for adaptation.
For mental health and wellbeing outcomes, we considered mental and behavioural disorders classified in the International Classification of Diseases 11th Revision (ICD-11) [39] or The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) [40], respectively, measured in the general adult population, as well as pertinent psychosocial proxies.Wellbeing was understood as a multidimensional construct encompassing different aspects such as good social relations, freedom of choice and action, security, health, and essential materials for living well and can be measured subjectively or objectively using composite indicators [41].
This systematic review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines [42].
The protocol for this systematic review was registered on PROSPERO (doi:10.15124/CRD42021262711).
We systematically searched seven databases that provide comprehensive coverage of research done in climate change, health, mental health, and LMICs (OVID MEDLINE, EMBASE, Global Health, PsycINFO, Web of Science Core Collection, COCHRANE and GreenFILE) for studies published from 1 January 2013 until 10 September 2022 with no language restrictions.We excluded papers published before 1 January 2013, using the 5th IPCC report-published in 2014-as a reference point [43].
We used a combination of MeSH (medical subject heading) terms and keywords related to climate change, mental health, wellbeing and LMICs.Our OVID MEDLINE search strategy is appended online (supplementary file 1).Additional records were identified from the outputs Scheelbeek et al [16] and colleagues reported using the 'Global Adaptation Mapping Initiative' (GAMI) database, which was constructed through systematic literature searches in Scopus, Web of Science and Google Scholar from 2013 to 2020 [44].The search methods of the GAMI database are made available in detail elsewhere [45][46][47].Finally, we conducted manual backward search of reference lists and a forward-citation search for all included papers and related reviews.

Eligibility criteria
Study inclusion and exclusion criteria were defined a priori (supplementary file 2).We included peerreviewed, published studies that: (1) examined mental health or wellbeing outcomes related to climate change mitigation and adaptation strategies in general adult populations (>18 years old) living in LMICs, (2) the studies could use controlled evaluations, quasi-experimental methods, pilot assessments or focussed case study designs to collect quantitative or qualitative data; (3) measured mental health and behavioural conditions measured using selfreport tool, assessments by mental health workers or broad wellbeing outcomes and psychosocial proxies; and (4) included indicators of successful mitigation and/or adaptation interventions linked to a change in mental health outcomes (e.g.change in depression scores or change in the proportion of those diagnosed with a mental disorder), change in social functioning skills (e.g.improved coping skills, social functioning, self-esteem) and any other secondary outcomes related to psychosocial conditions and wellbeing (e.g.quality of life) were also considered.

Selection process
We screened titles and abstracts initially and collated them using EndNote referencing software [48].After de-duplication, the first author (ECF) screened titles and abstracts against the eligibility criteria and uploaded the selected references for full-text screening into Rayyan [49].Approximately one-third of the articles and full-text screening was performed by two co-authors independently, who resolved disagreements through discussion.Articles fulfilling all the inclusion criteria were included in the review.See supplementary file 3 for the details of excluded studies.

Data extraction and analytic approach
All studies were in English except for one in Portuguese.This article was double translated into English and Spanish, and data were extracted by ECF, a native speaker of Spanish and fluent in English.

Quality assessment
Due to the variety of included study designs, we used the Specialist Unit for Review Evidence (SURE) for the critical appraisal of randomised controlled trials and other experimental studies [50], the Joanna Briggs Institute guidelines for quasiexperimental studies [51] and the Critical Appraisal Skills Programme checklist [52] to assess qualitative case studies.The quality assessment (supplemental file 4) did not exclude low-quality articles, but their limitations were discussed.

Data analysis
Due to the heterogeneity of research designs, assessment approaches, and strategies, it was not possible to pool the results for meta-analysis.Therefore, we provide a narrative description of the findings.

Study selection
The results of the search are summarised below in figure 1.A total of 9514 records were identified in the database search and an additional 18 were found through additional methods.
Fifteen studies were ultimately included in the review comprising data from 12 255 participants.

Study characteristics
Details for the 15 included studies are shown in table 1.

Sources of bias
Supplementary file 4 contains the results of the quality assessment.Generally, controlled, and experimental studies were scored as medium quality using the SURE checklist, and only three were appraised as high quality.The risk of bias was not discussed in five of the nine controlled studies, only three offered an appraisal of the generalisability of their results, and only four disclosed funding or conflict of interest information.Across the 13 quantitative studies, the statistical methods were described sparsely in three of   Validity testing of assessment tools for the study settings was largely absent, along with verification to establish credibility and reflexivity.Unvalidated tools may be culturally inappropriate or not accurately interpreted, leading to errors in responses, and translations might not convey the intended meaning accurately, leading to information bias.The evidence base could be improved by greater attention to sources of bias and appropriate generalisability of results.

Adaptation and mitigation strategies
The types of strategy included in the 15 studies had heterogeneous designs, and differed in their goals and scale, as the adaptation studies focused on localised interventions.Twelve studies (80%) examined the effects of single adaptation strategies across nine LMICs [28,53,54,56,57,[59][60][61][63][64][65][66].Of the studies that assessed air pollution, two were adaptation studies based on behavioural interventions; One study used an RCT design [53] (n = 110) and the other a field experiment [66] (n = 48) to evaluate external air pollution.Droughts were assessed in two adaptation studies based on cash transfer programmes for farmers.One was a randomised evaluation [56] of anti-poverty programmes implemented by the Brazilian government (n = 850), and the other (n = 100) was a quasiexperimental study [60].
Of the four studies assessing extreme climatic events, all were adaptation strategies.One study (n = 480) conducted a field experiment to decrease flood vulnerability [65], another one (n = 480) did an RCT on disaster preparedness [54], another (n = 100) used a quasi-experimental design of unconditional cash transfers to flood-prone rural communities [63], and the last one (n = 223) conducted a randomised evaluation of two governmental programmes aimed at vulnerable groups to climate stressors [64].A qualitative case study (n = 89) evaluated a planned relocation governmental programme for sea-level rise and coastal erosion [28].One adaptation study on deforestation and forest degradation was a randomised evaluation [59] (n = 400).
Meanwhile three studies (20%) examined the effects of mitigation programmes [55,58,62].For instance, the study by Williams (n = 180) used an RCT design to assess a household air pollution mitigation strategy involving cleaner cookstoves [55].Two other studies assessed the same multi-country deforestation and forest degradation mitigation strategy: one study [58] performed a randomised evaluation (n = 4000), and the other (n = 3754) had a quasi-experimental design [62].

Mental health and wellbeing outcomes
Most studies (12 out of 15) used quantitative methods to assess the outcomes of climate change mitigation and adaptation strategies on mental health and wellbeing.Only two included studies [54,63] used validated scales to assess common mental disorders.The study led by James et al [54] used the Zanmi Lasante Depression Symptom Inventory [67] (ZLDSI), the Modified Post Traumatic Syndrome Disorder Symptom Scale [68] (MPSS), the Beck Anxiety Inventory [69] (BAI), the functional impairment items tools adapted from Kaiser et al [70] and the adapted Social Cohesion.

Primary findings
The included studies had overall mixed outcomes; with most (8 out of 15) reporting positive effects of climate change mitigation and adaptation strategies on mental health [54,63] and wellbeing [53,55,57,59,60,65] In contrast, the remaining ones (7 out of 15) reported no significant impact [61] or mixed outcomes [28,56,58,62,64,66] within the intervention groups.None reported adverse effects.In general, the findings from the 15 studies provide important insights into the effects of these interventions on mental health and wellbeing outcomes.However, the lack of specific effect sizes limits our ability to fully assess the magnitude and practical significance of the observed improvements.
For example, the study led by Araban et al [53] obtained positive effects on the individual's perceived benefits and self-efficacy in the intervention group compared to the control group.Similarly, the study by Bedran-Martin [56], showed varied changes in subjective wellbeing and perception of material quality of life varied across groups, indicating small to moderate improvements between the intervention groups.Binh's study [65] reported positive findings for fear feelings, structural measures, livelihoods measures, and self-efficacy among the groups participating in the intervention.Davids et al [57] used a comprehensive approach across ecological, socioeconomic and health categories to assess the impact significance of wellbeing outcomes and found improved social-economic outcomes among the participants.Gori Maia et al [60] found positive associations between participants' wellbeing and income, work,     The survey data show that households who did not receive FbF assistance felt miserable or unhappy significantly more frequently after the flood than the intervention group who received cash assistance.Similarly, FbF-assisted households were significantly less likely to have felt anxious or depressed in the last seven days before the survey (29% vs. 43%) The FbF cash transfer increased the regularity and Quality of beneficiary households' food intake, reduced the need to take out high-interest loans and appears to have reduced psychosocial stress in the aftermath of the flood.The intervention may have also prevented households from having to make destitution sales of valuable assets when compared to similarly affected households.
(Continued.)    and life satisfaction.The study led by James et al [54] showed positive effects of the intervention on disaster preparedness and mental health outcomes, such as depression, trauma, anxiety, and functional impairment, as well as social outcomes, such as helpgiving and help-seeking behaviours.However, despite the positive effects found in the studies mentioned, the specific effect sizes values across the studies were not reported, it difficult to assess the magnitude of the improvements and the significance of these changes.Additionally, confirming the long-term effects of these interventions is challenging due to the varied evaluation periods and availability of post-intervention assessments.For example, five studies [55,57,63,65,66] did not report conducting follow-up assessments, and the remaining ten did.However, their timelines ranged from onemonth follow-up evaluation post-intervention [53] to 15 years [56], as in the study led by Bedran-Martins.
On the other hand, there were studies with mixed or non-significant changes among intervention participants.For instance, Duchelle's randomised evaluation of the anti-deforestation multicountry program [58] found mixed effects of specific intervention components across countries, highlighting the importance of local factors in real-life conditions and the need to prioritise meeting communities' needs.Additionally, qualitative evaluations conducted by Kundo et al [64] of two governmental programs for communities at high-risk for short and long-term climatic stressors and McMichael and Powell [28] on the longitudinal assessment of a relocated community due to coastal erosion and sealevel rise provided valuable insights into the intervention participants'perspectives but also obtained mixed results in terms of the perceived effectiveness and improvements that these strategies brought across regions.These findings highlight sociocultural, socioeconomic, and political factors' role in wellbeing indicators and emphasise the need to involve target communities into context-specific participatory design planning meaningfully.

Discussion
This systematic review summarises the existing evidence on the effects of climate change mitigation and adaptation strategies on mental health and wellbeing outcomes among adult populations living in LMICs.Most included studies focused on adaptation interventions, with only a few examining mitigation programmes.There was limited evidence on the effects of climate action on common mental disorders.Furthermore, no studies assessed the linkages between mental health variables and mitigation programmes.
The study designs, types of intervention, and their active components varied widely across studies, reflecting the diverse range of strategies being implemented, the different climatic hazards being addressed, and the various assessment tools and approaches used to measure mental health and wellbeing outcomes.
Factors significantly associated with wellbeing outcomes ranged broadly between studies, but most findings highlighted the critical role of contextual and sociocultural factors in achieving beneficial effects.For example, there was a consistent link between cash transfer programmes and integrated interventions that strengthen community ties and improve material living conditions or wellbeing.This findings aligns with the broader literature on underserved communities and climatic events [73] and external stressors [74].However, while cash transfers programs, especially unconditioned ones can increase participant's wellbeing levels by helping them meet their basic needs, they may require an integrated approach to achieve longer-term wellbeing effects, as reported elsewhere [75].Evaluations of anti-poverty governmental programs [56,64] implemented in underserved communities and multi-country antideforestation programs [58,62] highlighted the need for tailored community protective measures that go beyond providing access to cash funds for high-risk groups affected by climatic stressors.
Notably, none of the included studies reported on additional related mental health topics, such as forced migration, gender-based violence, or substance use.The limited evidence in this area may be attributed to mental health not being a primary focus of evaluations of climate change mitigation and adaptation strategies in LMICs [76] and the lack of validated scales and tools for measuring these outcomes in cobenefits studies in LMICs [77].
The reporting of gender-disaggregated data across the included studies was scarce.Women, who often experience higher rates of mental conditions, primarily due to depression [78], are disproportionately affected by the impacts of climate change [79].Given that nine out of the 15 included studies assessed populations living in high-risk areas for cyclical extreme weather events, the lack of reported outcomes with gender-differentiated data is concerning considering the increased economic pressures faced by female beneficiaries of climate mitigation and adaption programmes.Women often become heads of households after extreme weather events [80], experience displacement [81], partner's economic migration or endure gender-based violence [82], all of which have well-documented mental health consequences [13].Ensuring equal inclusion in leadership and decisionmaking of women and minorities, especially those belonging to Indigenous groups in high-risk areas for climatic stressors, is crucial to address their mental and wellbeing needs while incorporating their unique knowledge of ecosystem handling and protection.
The relationship between the co-benefits of adaptation and mitigation strategies and mental health outcomes among LMIC populations is still largely unknown, with limited quantitative research to date.Two studies that measured mental health outcomes quantitatively were also limited by methodological constraints in conducting research in humanitarian settings.One study [54] conducted 3 day mental health integrated disaster preparedness group intervention, used validated scales and conducted followup assessments three and six months after the study.The other study [63] provided unconditional cash transfers in anticipation of extreme weather events, used a survey with a shortened version of a standardised scale, and did not report a follow-up assessment, limiting the understanding of the temporal relationship between these strategies and the possible mental health co-benefits they bring to beneficiaries and communities.
The countries and regions identified as having extensive exposure to climate change hazards are primarily located in the tropics and subtropics [83].With large regions affected by climate change hazards, Brazil has the largest population exposed to wet-bulb temperatures of 30 • C and above [84].This review's findings align with this evidence, as 5 out of 15 studies were conducted in Brazil.Peru and Indonesia were the next most common countries, with three studies each.
Most studies (12 out of 15) were implemented in rural or peri-urban villages located in various settings and exposed to different environmental threats, providing a clearer understanding of where these strategies can potentially have an impact.However, various methods were used to measure the most frequent wellbeing outcomes, and most studies did not report their translation process or validation of the surveys or tools used for individual data collection, which may weaken the reliability of the findings.Future research should incorporate validated tools to provide more accurate data on the impact of these strategies.The absence of widespread formal evaluations of these strategies 'mental health and wellbeing outcomes limits policymakers' ability to make informed decisions considering the holistic impact of climate change mitigation and adaptation strategies at both population and individual levels.
Despite the increase in recent evidence on the threats of climatic hazards and their impacts on health and wellbeing, global estimates and projections often need to be revised at regional and local levels.Higher temperatures and various extreme weather events may have different effects in different areas.However, social vulnerability factors and individual susceptibilities mediate their local impact on human populations, such as the marginalisation of certain groups like Indigenous People, lack of communication and support features for rural villages, poorly planned urban and peri-urban characteristics, and high prevalence of comorbidities.These factors tend to increase the risk of adverse health outcomes within populations [8,10].

Strengths and limitations
The strengths of this review lie in the comprehensiveness of the search strategy and the rigorous inclusion criteria used.We included controlled, quasiexperimental, and pilot studies and focused case studies that reported on the impact of climate change mitigation and adaptation strategies on mental health and wellbeing outcomes.Also, only one included study [54] directly focused on mental health outcomes rather than assessing mental health as a secondary benefit of other climate adaptation activities.This aligns with the broader lack of research examining mental health as a primary outcome in climate change intervention studies [7,85,86].The shortage of studies focused specifically on mental health measures highlights a key gap in the evidence base and underscores the need for future intervention studies to deliberately incorporate and prioritise validated mental health assessments.The limited number of studies that met the inclusion criteria underscores the need for further research in this area.
Nevertheless, as awareness of the potential mental health and wellbeing co-benefits of mitigation and adaptation efforts increases, these aspects are expected to be more deliberately considered to augment population benefits.However, more research is needed to strengthen this review's relatively weak evidence base.Our restriction to adult populations may have omitted overarching evidence across the lifespan.However, this approach is justified since most participants and beneficiaries of these strategies and programs are adults.Additionally, four studies included subpopulations with increased vulnerability to risk factors, such as older adults [66], youth [59,64], indigenous women [55] and pregnant women [53].
This review included published peer-reviewed studies reporting quantitative and qualitative outcomes in English and Portuguese.Data extraction was completed by a single author, which introduces the potential for selection and extraction bias.However, this bias is mitigated by oversight and discussion with a second author during the screening, data extraction and quality appraisal processes.Future review should also consider including grey literature for a more comprehensive search in this area.Due to the heterogeneity of outcomes, conducting meta-analysis or meta-synthesis of quantitative and qualitative studies was impossible, thereby preventing the pooling of results.

Future research recommendations
Further research should focus on collecting more data targeting local population groups with heightened vulnerabilities.This will contribute to a more comprehensive understanding of the cross-cultural impacts of these strategies.Detailed and countryspecific evaluation analyses and focused data on the most affected groups are needed to inform policymakers, the public, and key stakeholders.Additionally, joint co-design of targeted interventions with the communities at the forefront of adaptation efforts, ensuring research equity and inclusion, is crucial to understand better the magnitude of climate change impacts on population health and wellbeing and to identify and leverage the protective factors of mitigation and adaptation programs.More attention and efforts should be directed towards the potential negative impacts of implemented mitigation and adaptation strategies, such as displacement through relocation [64] and loss of livelihoods [58].This can be achieved by more frequent and better measurement of mental health outcomes, considering such potential negative impacts, and ensuring that they are minimised with strong, culturally sensitive coproduced, and participatory local adaptation measures.We have included studies that have assessed mental health and wellbeing outcomes at the individual level but there are also social-ecological level factors with an undeniable influence at both the individual and the community level, which should be explored accordingly.Furthermore, strategies should also ensure that affected communities are adequately compensated for economic and material losses and empowered to face the effects of climate change.
It is crucial to recognise that populations living in LMICs are among the most vulnerable and neglected groups, often lacking support from their governments.They have been forced to be at the forefront of adaptation activities, with little or no engagement from local authorities.Therefore, their needs, vulnerabilities and contextual factors must be considered when scaling up multisectoral approaches that harness the co-benefits of these strategies to alleviate the burden on their mental health and wellbeing.
Addressing these potential co-benefits for populations living in LMICs requires a holistic and transdisciplinary approach.It is essential to consider the specific needs and vulnerabilities of target population groups, including those living with disabilities, women, the elderly, and youth, living in highrisk areas for climatic events and environmental hazards in LMICs.This consideration ensures that these strategies are practical, equitable and capable of bringing population-wide indirect effects that positively impact sustainable development, poverty reduction and wellbeing in these countries, although more evidence is still needed.
Our findings should be interpreted with caution due to the possibility of reporting and publication bias.Additionally, the small number of studies, the lack of specific size values reported, and the heterogeneity of the study designs and populations make it challenging to draw firm conclusions.Further research is needed to fully understand the potential co-benefits of these strategies for mental health and wellbeing in LMIC settings.
The results of this review underscore the need for greater attention to the psychosocial impact of climate change mitigation and adaptation strategies, both in terms of measuring mental health and wellbeing as outcomes, and in designing interventions.The concurrent global climate and mental health crises require the prioritisation of evidence-based policies that prioritise the mental health and wellbeing of the population.Such policies should promote preparedness, resilience, and recovery facing climate change effects, foster social cohesion and community engagement, and empower individuals and communities in LMICs.

Conclusion
This review identified limited and disparate evidence regarding the effects of climate change mitigation and adaptation strategies on mental health and wellbeing in LMICs.Despite the widespread implementation of programming in this area, formal evaluations that measure these critical outcomes are lacking.Given the current global climate and mental health crises, this scarcity of evidence represents a missed opportunity to address significant long-term problems for population mental health and wellbeing.Urgent research is needed to explore how these interventions work and how to better address mental health responses, considering local factors and adopting a transdisciplinary approach at all levels to facilitate the translation of findings into policy and action.

Figure 1 .
Figure 1.PRISMA flow diagram of study selection.

Figure 2 .
Figure 2. Map with included studies distribution.

Table 1 .
General characteristics and summary results of the studies included in the review, grouped by study design (n = 15).

Table 2 .
Characteristics of the interventions included in the review, grouped by study design (n =

Table 2 .
a Brazilian Forest Code states that 20% of native habitat in semiarid regions must be maintained and conserved.b Livelihood has been described as assets, capabilities and activities to provide a living (Scoones 1998:5).RCT: randomised controlled trial; WWWC: Wise Wayz Water Care programme; REDD+: Reducing carbon Emissions through avoided Deforestation and forest Degradation and enhancement of carbon stocks; MAIS: Módulo Agroclimático Inteligente e Sustentátvel; EGPP: Employment Generation Programme for the Poorest; NJLIP: Nuton Jibon livelihood Improvement Project; FGD: focus group discussion; LPG: liquefied petroleum gas; FbF: forecast-based cash transfer; FMNR: Farmer-Managed Natural Regeneration project.

Table 3 .
Adaptation or mitigation and mental health & wellbeing assessments characteristics of the studies included in the review, grouped by study design (n =