Introduction
With approximately one billion highly vulnerable people at risk from the adverse impacts of climate change, the urgency of mitigation cannot be overstated. The world is far from being on track from the maximum 1.5°C change, recommended by scientists (Fig. 1).
Low-income communities, dependent on local natural resources, are particularly threatened as we witness unprecedented rates of ecosystem loss. This alarming trend not only exacerbates climate change but also amplifies its impacts, highlighting the intertwined challenges of land degradation, biodiversity loss, and global warming.
Fig. 1. Average global air temperature compared with pre-industrial level (source: Era5, C3S/ECMWS)
Nature-based solutions (NbS) have emerged as a promising approach to address these interconnected crises. By leveraging natural processes, such as those found in forests and wetlands, NbS offer a sustainable pathway to reduce greenhouse gas emissions and enhance ecosystem resilience. Recent reports suggest that NbS could account for up to 30% of the world's mitigation potential, making them a crucial component in the global strategy to combat climate change and limit warming to the 1.5°C threshold [1].
Understanding Nature-Based Solutions
NbS are interventions that involve the conservation, management, and restoration of ecosystems to address climate change challenges while providing co-benefits for human development and biodiversity [2]. They are designed to deliver measurable climate adaptation and mitigation benefits, improving ecosystem functionality and resilience against anticipated climate risks.
NbS are informed by the best available scientific knowledge, synergistic in reducing emissions and human vulnerability, co-designed with local stakeholders, and measurable through robust monitoring frameworks.
Examples of NbS include a variety of interventions such as:
Reforestation: Planting trees to restore forests and increase carbon sequestration.
Wetland restoration: Reviving wetlands to enhance water filtration, reduce flooding, and support biodiversity.
Urban green spaces: Creating parks, green roofs, and gardens to improve air quality, reduce urban heat islands, and provide recreational areas for communities.
NbS are actions that work with and enhance nature to help address societal challenges, offering a harmonious approach to environmental, social, and economic issues [3]. Fig. 2 highlights the environmental, social, and economic benefits of implementing NbS and it can be seen that NbS represent a holistic approach to climate change mitigation, leveraging nature's inherent processes to build a sustainable and resilient future.
Fig. 2. Environmental, social, and economic benefits of implementing NbS
Nature-Based Solutions in Infrastructure Climate Change Mitigation
NbS play a crucial role in capturing and storing CO2e, thereby mitigating climate change. Afforestation and reforestation projects involve planting trees to create new forests or restore degraded ones, which sequester carbon as trees grow. Soil conservation techniques, such as cover cropping and reduced tillage, enhance soil organic matter, trapping carbon within the soil. These approaches not only reduce atmospheric CO2e levels but also improve soil health and agricultural productivity [4].
NbS enhance biodiversity and provide essential ecosystem services that support climate resilience [5]. By protecting and restoring diverse habitats, NbS maintain the ecological balance necessary for species survival. Healthy ecosystems offer services such as water purification, flood regulation, and pollination, which are vital for human well-being and agricultural stability. Biodiverse ecosystems are more resilient to climate impacts, as they can better adapt to changes and recover from disturbances.
Several case studies illustrate the successful implementation of NbS in climate change mitigation:
Natural England Projects: Natural England has funded six projects focused on nature restoration for carbon sequestration, each covering areas greater than 500 hectares.
Silvopastoral Systems in Colombia: Livestock-based agriculture is a significant source of emissions and a critical income source in Colombia, which helps to reduce emissions while sustaining farmers' livelihoods.
Guyana’s REDD+ Project: it maintained the national deforestation rate at 0.1%. It also provides financial mechanisms for a national carbon credit strategy, incentivizing forest conservation.
Vida Manglar Project: This project collaborates with local communities to restore and protect 11,000 hectares of mangrove forest along the Caribbean coast.
Hinewai Reserve in New Zealand: Covering 1,250 hectares, the Hinewai Reserve is a privately owned nature regeneration project focusing on restoring endemic plants and animals.
Implementing Nature-Based Solutions in Engineering and Construction
NbS can be effectively integrated into urban planning and infrastructure projects to enhance sustainability, resilience, human and ecological well-being [6]. Urban planners can incorporate green roofs and walls, which provide insulation, reduce the urban heat island effect, and capture stormwater, thus reducing runoff and flooding. They can also bulit parks, urban forests, and sustainable drainage systems which not only sequester carbon but also improve air quality and provide recreational spaces, contributing to the overall well-being of urban populations.
Innovative engineering practices are increasingly leveraging NbS to enhance infrastructure resilience and environmental benefits. Bioengineering techniques, such as planting native vegetation buffers to stabilize shorelines, provide coastal protection by reducing erosion and buffering against storm surges. Living shorelines, which combine plants, sand, and rock, create habitats for marine life while protecting coastal areas from erosion (Fig. 3). These techniques are often more cost-effective and sustainable compared to traditional hard engineering solutions, such as concrete seawalls and hard shorelines, and they offer additional ecological benefits.
Fig. 3. Bioengineering techniques for coastal protection (source: UMCES)
Implementing NbS in engineering and construction faces several challenges, including technical, financial, political and regulatory barriers (Fig. 4). Technically, integrating NbS requires multidisciplinary knowledge and expertise, which can be addressed through cross-sector collaboration and training. Financially, the initial costs of NbS may be high, but long-term savings from reduced maintenance and enhanced ecosystem services can offset these costs.
Governments and private sectors can incentivize NbS through grants, subsidies, and public-private partnerships. Regulatory barriers, such as outdated building codes and zoning laws, can hinder NbS adoption. Updating regulations to incorporate NbS standards and promoting policy frameworks that support sustainable practices can overcome these obstacles. Public awareness campaigns and stakeholder engagement are also crucial in building support for NbS initiatives.
![Fig. 4. Barriers to implementing NbS and possible solutions (reproduced from [7])](https://static.wixstatic.com/media/a08c91_b1a641e5ba18439bb16fdfd7200698af~mv2.png/v1/fill/w_79,h_71,al_c,q_85,usm_0.66_1.00_0.01,blur_2,enc_auto/a08c91_b1a641e5ba18439bb16fdfd7200698af~mv2.png)
Fig. 4. Barriers to implementing NbS and possible solutions (reproduced from [7])