Institutional and social trust as determinants of SDG 13 implementation in low- and middle-income countries: A mixed-methods systematic review

The world is running behind on SDG 13. At the halfway point to the 2030 deadline, SDG 13 is among the goals making only limited progress globally (Sachs et al., 2023). Current Nationally Determined Contributions (NDCs) are collectively insufficient to meet the Paris Agreement's temperature targets. A significant gap persists between what countries have committed to and what policies are actually in place (Roelfsema et al., 2020). To stay within 1.5°C of warming, global emissions need to fall by roughly 42% by 2030. Current pledges indicate only a 0.3% reduction, essentially no change (UNEP, 2023). The burden of this failure falls disproportionately on low- and middle-income countries (LMICs). NDC implementation in Least Developed Countries is contingent on external finance in 93.5% of cases and on technology transfer in 89.1% of cases, conditions that have been systematically unmet (Mehrotra & Benjamin, 2022). Climate finance reached only $89.6 billion of the $100 billion per year promised to developing countries by 2021 (Garschagen & Doshi, 2022; Omukuti et al., 2022). Adaptation funds reach the most vulnerable countries inconsistently. Understanding what enables climate action to succeed in LMIC contexts is therefore urgent. Studies increasingly argue that successful climate governance depends on more than formal policy instruments. Trust also plays a critical role. Ostrom (2009) identified trust as central to collective action and the sustainable governance of shared resources. This insight applies directly to the multilevel challenges of climate governance. Adger (2003) showed that social capital grounded in trust is a foundational determinant of adaptive capacity, particularly in communities with limited state support. Newton and Zmerli (2011) established that social and political trust are positively associated constructs. Together, they underpin collective governance and public goods provision mechanisms essential to delivering climate outcomes at scale. Meta-analytic evidence confirms that trust matters empirically. A synthesis of 141 correlations from 51 studies found that trust in scientists and environmental experts is among the strongest predictors of climate mitigation and adaptation behaviours (Cologna & Siegrist, 2020). Domain-specific institutional trust, meaning trust in institutions' capacity to act on climate change, is also positively associated with public climate-related behaviours (Cologna & Siegrist, 2020). Cross-national research further demonstrated that trust in both law-making and law-enforcing institutions predicts climate policy preferences across diverse national contexts (Davidovic & Harring, 2020). Notably, trust in impartial institutions is more consistently influential than trust in elected politicians (Kulin & Johansson Sevä, 2020). Despite this evidence, most studies are cross-national attitudinal surveys conducted in high-income settings. Few examine implementation outcomes in LMICs (Cologna & Siegrist, 2020). The limited LMIC-focused evidence suggests trust operates differently where state capacity is limited. In Zimbabwe, local climate adaptation frameworks have been found to break down not from lack of awareness, but from distrust in governmental delivery (Mubaya & Mafongoya, 2017). These findings point to a consistent pattern: where trust is absent or damaged, climate action stalls regardless of what formal policies say. No systematic review has yet consolidated empirical evidence on how institutional and social trust influence SDG 13 implementation in LMICs. This review addresses that gap. It synthesises findings across quantitative, qualitative, and mixed-methods studies. The goal is to build an integrative understanding of trust as a governance enabler and barrier for achieving SDG 13, where the consequences of failure are most severe.