Nature-based solutions (or nature-based systems, abbreviated as NBS or NbS) are methods that use natural ecosystems and natural processes to solve social and environmental problems. These problems include reducing the effects of climate change, ensuring access to clean water and food, and reducing the risk of natural disasters. The goal is for strong and healthy ecosystems—whether natural, managed, or created—to provide benefits for people and protect biodiversity. The 2019 UN Climate Action Summit recognized nature-based solutions as a useful way to address climate change. For example, nature-based systems can help with climate change by managing floods, restoring natural barriers along coasts, and reducing heat in urban areas.
The idea of NBS is connected to other fields, such as ecological engineering, ecosystem-based adaptation, and ecological restoration. A key part of using NBS is managing natural resources in a way that supports long-term environmental health.
Restoring mangrove forests along coastlines is an example of a nature-based solution. Mangroves help protect coastal communities by reducing the force of waves and wind. They also absorb carbon dioxide from the air and provide habitats for young marine animals, which supports fishing industries. Additionally, mangroves help prevent erosion caused by rising sea levels.
In cities, green roofs, blue roofs, and green walls (part of green infrastructure) are nature-based solutions. These features can lower urban temperatures, collect rainwater, reduce pollution, and store carbon. They also help support plants and animals in urban areas.
Nature-based solutions are increasingly included in national and international climate policies, infrastructure projects, and funding programs. The European Commission has focused more on NBS since 2013. Many global examples of NBS studied by Debele et al. (2023) are from Europe. While there is potential to use NBS more widely around the world, challenges often arise during planning and implementation.
The IPCC noted that the term "nature-based solutions" is still being discussed, with concerns that it might suggest NBS alone can solve climate change. To clarify, the IPCC emphasized that nature-based systems cannot replace the need to reduce greenhouse gas emissions significantly.
Definition
The International Union for Conservation of Nature (IUCN) explains that Nature-Based Solutions (NBS) are actions that help protect, manage, and restore natural or changed ecosystems. These actions solve problems that people face, like climate change, food shortages, reducing disaster risks, and ensuring safe water supplies. At the same time, they help both people and wildlife.
In simpler terms, NBS are ways to use healthy ecosystems to protect the environment. These methods also offer many benefits, such as helping the economy and improving people’s lives. They are used to reduce the effects of climate change and to prepare for its impacts.
The European Commission describes NBS as solutions inspired by nature. These solutions are cost-effective and provide benefits for the environment, society, and the economy. They also help make communities stronger by bringing more natural elements into cities, landscapes, and oceans. In 2020, the European Commission updated its definition to stress that NBS must help protect wildlife and support the services that ecosystems provide, such as clean air and water.
The IPCC Sixth Assessment Report noted that the term "Nature-Based Solutions" is used often in scientific studies, but not always in the same way. In 2017, scientists said the term was not clearly defined and unclear.
Ecosystem-Based Adaptation (EbA) is a type of NBS. It focuses on keeping ecosystems and people safe from the harmful effects of climate change.
The term NBS was first used by people working in the field in the late 2000s. At that time, groups like the IUCN and the World Bank used it to describe new ways to reduce and prepare for climate change by working with natural ecosystems instead of only using engineering methods.
Many Indigenous communities have long believed that the natural world is important for people’s well-being, as part of their traditional knowledge. This idea became part of modern science in the 1970s with the idea of ecosystem services.
The IUCN mentioned NBS in a report for the United Nations Framework Convention on Climate Change. European leaders, especially the European Commission, also used the term in a report that said NBS can create jobs and support economic growth as part of a green economy. The term became more widely known in the media around the time of the Global Climate Action Summit in California in September 2018.
Objectives and framing
Nature-based solutions focus on using natural resources in ways that help solve problems affecting the environment, society, and the economy. These solutions go beyond simply protecting nature by emphasizing how human well-being, reducing poverty, and improving society and the economy can be connected to nature. They also consider how rules and leadership can support these efforts.
The main goal of nature-based solutions is to manage and use natural resources wisely to address challenges faced by people. However, different groups have different ways of understanding these solutions. For example, the International Union for Conservation of Nature (IUCN) believes that well-managed and restored ecosystems are central to nature-based solutions. Their main aim is to help society reach its development goals while protecting human health and happiness, respecting cultural values, and strengthening ecosystems so they can recover and provide benefits.
The European Commission highlights that nature-based solutions can turn environmental and social problems into chances for innovation. By using natural resources as a way to support growth and development, these solutions can bring more natural elements, such as plants, water, and wildlife, into cities, countryside, and oceans. These actions are adapted to local needs, use resources efficiently, and work together to solve problems. As a result, nature-based solutions are seen as a way to stop and reverse the loss of nature by 2030 and fully restore nature by 2050.
Categories
The IUCN suggests that NBS is a broad idea that covers many different methods. The IUCN lists different types and examples of NBS methods.
Types
Scientists have created a classification system to describe Nature-Based Solutions (NBS) based on two factors:
- The amount of engineering or human involvement in changing ecosystems, and
- The number of ecosystem services (benefits provided by nature) and groups of people affected by a specific NBS.
This system shows that NBS can involve different ways of working with ecosystems, such as protecting them, managing them, or even creating new ecosystems. It also explains that the more ecosystem services and groups of people an NBS tries to help, the harder it may be to fully meet the needs of all groups at the same time.
There are three main types of NBS, though some solutions may mix features of different types in different areas or over time. For example, combining protected and managed areas in a landscape can help achieve multiple goals.
Type 1 involves little or no changes to ecosystems, with the goal of keeping or improving ecosystem services in and around these areas. Examples include protecting mangroves in coastal regions to reduce risks from extreme weather, and creating marine protected areas to preserve biodiversity while allowing fish and other resources to move to fishing areas. This type is similar to the idea of biosphere reserves.
Type 2 includes managing ecosystems in ways that make them more sustainable and useful for many purposes. These methods improve specific ecosystem services compared to traditional approaches. Examples include planning agricultural areas to support multiple uses, using existing plant diversity to boost biodiversity and resilience, and improving tree and genetic diversity to help forests survive extreme events. This type is closely related to practices like agroforestry.
Type 3 involves managing ecosystems in very simple ways or creating entirely new ecosystems, such as man-made environments like green roofs and walls to cool cities and clean polluted air. This type is connected to ideas like building green and blue infrastructure (such as parks, wetlands, and water systems) and restoring damaged or polluted areas. An example is constructed wetlands, which help clean water and support wildlife.
Applications
The 2019 UN Climate Action Summit showed that nature-based solutions (NBS) are a helpful way to fight climate change. For example, NBS can include managing floods naturally, restoring coastal barriers, cooling areas naturally, and restoring natural fire patterns.
The Paris Agreement asks all countries to recognize how natural ecosystems help provide services like storing carbon. Article 5.2 encourages countries to use conservation and management to increase carbon storage. Article 7.1 encourages countries to strengthen the ability of communities and ecosystems to survive challenges by diversifying economies and managing natural resources sustainably. The Agreement mentions nature (ecosystems, natural resources, forests) in 13 different places. A detailed review of climate pledges from 130 countries (65% of signatories) found that most included NBS in their plans. This shows many countries agree that nature can help meet climate goals. However, strong actions to support these plans are often not carried out.
A global study mapped evidence to show how well NBS work for climate change adaptation. After analyzing 386 case studies using computer tools, the study found that NBS were as effective, or more effective, than traditional flood management methods. In 66% of cases, ecological improvements were reported. In 24%, no change in ecological conditions was noted. Less than 1% reported negative effects. NBS also had better social and climate benefits compared to other methods.
At the 2019 UN Climate Action Summit, NBS was a major topic discussed as a way to fight climate change. A group called the "Nature-Based Solution Coalition" was formed, with many countries joining, led by China and New Zealand.
Since around 2017, many studies have suggested ways to plan and use NBS in cities.
It is important to use both grey infrastructure (like concrete systems) and green infrastructure (like natural systems) together. Studies show that while NBS improves flood resilience, it works best when combined with grey infrastructure. Using only green or only grey systems is less effective. When used together, these systems improve flood management, social conditions, carbon storage, and city planning for resilience.
In the 1970s, the U.S. used Best Management Practices (BMP) to model infrastructure after nature. The UK used "sustainable drainage systems" for flood control. Australia developed "Water Sensitive Urban Design" (WSUD) in the 1990s, and the U.S. created "Low Impact Development" (LID). New Zealand later adapted LID into "Low Impact Urban Design and Development" (LIUDD), focusing on involving many groups. In the 2000s, the western hemisphere widely used "Green Infrastructure" for stormwater management and to improve social, economic, and environmental conditions.
In China, the National Government’s Sponge Cities Program uses a mix of green and grey infrastructure in 30 cities to manage flooding and reduce climate risks after rapid urban growth.
For water issues, NBS can:
– Use natural processes to increase water availability (e.g., keeping soil moist, recharging groundwater),
– Improve water quality (e.g., using wetlands to treat wastewater, planting buffer strips along rivers), and
– Reduce risks from water-related disasters and climate change (e.g., restoring floodplains, building green roofs).
The UN has promoted NBS by using themes like "Nature for Water" for World Water Day 2018 and a report titled "Nature-based Solutions for Water."
For example, the Lancaster Environment Centre has tested flood management in different areas using software to calculate how floodplains expand during storms. The goal is to redirect large floodwaters into storage areas in the landscape.
Restoring forests helps both wildlife and people (e.g., providing food, wood, and medicine). Diverse, native trees are more likely to survive climate changes than single-species plantations. Expanding agriculture has caused most global deforestation. Between 2010 and 2020, forests were lost at about 4.7 million hectares per year. During the same time, Asia, Oceania, and Europe had the most forest growth. Restoring forests as part of national plans can help countries reach sustainable development goals. For example, Rwanda started a forest restoration program in 2015 with help from the World Resources Institute and IUCN. NBS methods used included ecological restoration and ecosystem-based solutions to address food and water security and reduce disaster risks. The Great Green Wall, a joint African effort to stop desert expansion, began in 2007.
Implementation
Many studies and reports have created rules and plans to help use Nature-Based Solutions (NBS) in the best way possible. One important rule is that NBS should work with, not take the place of, natural conservation efforts. NBS can be used alone or together with other ways to solve problems, such as technology or engineering, and are used across large areas of land.
Researchers have said that instead of seeing NBS as a replacement for man-made solutions, it is better to find ways for different solutions to work together.
The idea of NBS is becoming more accepted by people outside of the conservation field, such as those who plan cities. NBS are now being included in policies and programs related to climate change, laws, building projects, and funding, even though there are still many challenges to using NBS successfully.
Several examples have shown that NBS can sometimes cost less than traditional technology-based projects.
To use NBS, steps like changing how money is given as support for certain activities and creating ways to fund conservation efforts are needed.
NBS depend on the natural and cultural features of a place, including knowledge from local people, scientists, and traditions. Tools called Geographic Information Systems (GIS) can help choose areas that might work well for NBS. GIS looks at things like land slopes, water sources, how land is used, and soil types to find the best places for NBS. These maps are often combined with old flood maps to study how well certain areas can store floodwater using 3D models.
Since 2016, the European Union has helped create a group (called ThinkNature) where people from many different areas can work together to design, test, and use new NBS ideas. This kind of group that brings together science, policy, business, and society may help more people use NBS. This project was part of the EU's Horizon 2020 program and lasted for three years.
In 2017, during Estonia’s time leading the European Union, the Estonian Ministry of the Environment and the University of Tallinn held a conference called "Nature-based Solutions: From Innovation to Common-use." This event aimed to help different groups work together on NBS projects, focusing on policies, research, and new ideas.
Concerns
The Indigenous Environmental Network has said that "Nature-based solutions (NBS) is a way to hide real problems and does not fix the main causes of climate change." They also mentioned that "the history of colonial rule continues through nature-based solutions." For example, NBS activities might include changing non-forest land into forest plantations to help reduce climate change, but this can cause unfairness by taking land from farmers and herders.
The IPCC noted that the term "nature-based solutions" is still being debated, with worries that it might make people think NBS alone can solve climate change worldwide. To explain further, the IPCC stated that "nature-based systems cannot be seen as a replacement for, or a reason to delay, large reductions in greenhouse gases."
Most examples and studies about NBS come from the Global North, which means there is little information about how well NBS works in many countries with medium or low incomes. Because of this, many ecosystems and climates in these areas are not included in current research or cost studies. More research is needed in the Global South to understand how effective NBS is for climate, social, and environmental goals.
Related concepts
NBS is connected to ideas such as ecosystem approaches and ecological engineering. These ideas include things like ecosystem-based adaptation and green infrastructure.
For example, ecosystem-based approaches are being used more often for climate change adaptation and mitigation by groups like the United Nations Environment Programme and non-governmental organizations such as The Nature Conservancy. These groups describe "policies and measures that consider the role of ecosystem services in reducing society's vulnerability to climate change, using a multi-sectoral and multi-scale approach."