Green infrastructure, also called blue-green infrastructure, is a system that helps solve problems in cities and with the environment by working with nature. This system includes managing rainwater, helping cities adapt to climate changes, reducing the effects of heat, increasing plant and animal life, growing food, improving air quality, creating clean energy, providing clean water, and keeping soil healthy. It also helps improve people's lives by offering places for recreation, shade, and shelter in and around towns and cities. Green infrastructure creates a natural framework that supports the health of communities, the economy, and the environment. Recently, experts and activists have also encouraged green infrastructure that helps everyone have equal access to nature-based services, instead of continuing unfair patterns.

Green infrastructure is a part of "Sustainable and Resilient Infrastructure," a term explained in standards like SuRe. It can also refer to "low-carbon infrastructure," such as systems for renewable energy and public transportation. Blue-green infrastructure may be part of "sustainable drainage systems" or "sustainable urban drainage systems" (SuDS or SUDS), which manage water quality and quantity while improving biodiversity and making areas more pleasant for people to live in.

Introduction

Nature can help protect communities from problems like flooding or extreme heat. It can also improve the quality of air, soil, and water. When people use natural systems as part of their infrastructure, it is called "green infrastructure." Many projects model this after prairies, where soil soaks up water and plants remove pollutants. Green infrastructure works at different sizes, but it is most often linked to green stormwater systems. These systems are smart and save money. However, green infrastructure is an extra part of other systems and helps create a healthy environment for people, the economy, and nature.

"Blue infrastructure" refers to water-related structures in cities, such as rivers, lakes, and ponds. These features can be natural or added during city planning. Coastal areas may use parts of the shoreline in their designs, like harbors and piers. Blue infrastructure supports life in water, such as insects, frogs, and birds. It also helps people by improving their health and happiness. In cities, accessible blue infrastructure is called "blue spaces." Blue and green infrastructure often work together and are sometimes called "blue-green infrastructure."

Terminology

Ideas for green urban structures started in the 1870s with plans for urban farming and garden spaces. Other terms used to describe these ideas include stormwater best management practices, source controls, and low impact development (LID) practices.

In the mid-1980s, new plans for managing stormwater were introduced to help reduce runoff, prevent erosion, and recharge groundwater. In 1987, changes to the U.S. Clean Water Act added rules to manage pollution from urban areas, requiring practices that handle runoff at its source instead of using traditional drainage systems. In 1990, the U.S. Environmental Protection Agency (EPA) created rules for municipal separate storm sewer systems (MS4s), which required large systems to make stormwater pollution prevention plans and use "source control practices." In 1993, the EPA published a handbook that listed stormwater management methods, such as using plants, filters, and porous pavement. Rules for smaller cities were added in 1999. MS4s provide drainage for over 80% of the U.S. population and cover 4% of the country’s land.

Green infrastructure is a concept that shows how natural environments should be considered in land-use planning. However, there is no single, widely accepted definition for the term. It is also called "blue-green infrastructure" or "green-blue urban grids" and is used by many fields, including design, conservation, and planning. These terms often include stormwater management, climate adaptation, and creating green spaces that serve multiple purposes.

Sometimes, the term "green infrastructure" is expanded to "multifunctional" green infrastructure. This means combining different uses or functions on the same piece of land. The EPA later used the term "green infrastructure" to describe managing stormwater runoff at the local level using natural systems or systems that copy natural processes. This helps improve natural ecosystems, even though it is not the main focus of the concept.

The term "blue-green infrastructure" is often used in urban areas and focuses more on managing stormwater as a key part of creating sustainable, multifunctional cities. At the building level, "blue-green architecture" is used, which applies similar ideas on a smaller scale. This includes using water from sources like grey water and rainwater for building greening and water management.

As mentioned, the term Green Infrastructure (GI) now includes topics like walking and cycling paths and renewable energy, which has caused confusion for stormwater experts. To clarify, stormwater professionals in the U.S. created the term Green Stormwater Infrastructure (GSI) in the 2010s. GSI is more specific to stormwater management and separates it from other GI topics. GSI often refers to small-scale projects, such as stormwater curb extensions, tree well filters, and pervious pavement. It can also describe large projects that manage runoff from large areas of land. Many cities and regions in the U.S. have created guides, such as the GSI Handbook developed by the Santa Clara Valley Urban Runoff Pollution Prevention Program in California.

History

The term "green infrastructure" was first used in the early 1990s. However, the idea of using natural spaces to support communities existed long before that. In 1994, Buddy MacKay, who led the Florida Greenways Commission, wrote a report to Florida’s governor about a project from 1991 called the Florida Greenways Project. He said, "Just as we plan roads, water, and electricity for our communities, we must also plan and manage natural spaces like green areas."

In ancient China, gardens were designed to show the beauty of nature in cities. These gardens, which began during the Shang Dynasty (1600–1046 BC), allowed native plants to grow naturally without human interference. This helped create peaceful, natural spaces in urban areas.

In ancient Greece, people used a public space called the agora for meetings and conversations. Many agoras were built across Greece, and some included natural elements like trees and plants. These spaces gave people a chance to enjoy nature while being part of the community.

A common feature in cities is the lawn, which is an area covered with short grass and sometimes other plants. While modern artificial lawns can harm the environment, historical lawns were more sustainable. They helped support wildlife and native plants, and today’s lawn designs are inspired by these older, greener examples.

In medieval Europe, lawns filled with flowers and plants, called "flower meads," were used to create sustainable green spaces. Later, during the Edwardian Era, lawns with thyme plants were planted because their flowers attracted insects and helped support biodiversity. In the 20th century, a type of lawn called "enamelled mead" was used in England for both beauty and to help manage rainwater.

During the Renaissance, public spaces like parks and gardens became common in cities. These areas were chosen carefully to provide places for people to gather and relax. They also helped improve the look of cities and provided fresh air, which reduced the heat in urban areas.

The idea of green infrastructure in Europe began in the 17th century in France. French cities used nature to organize public spaces and provide areas for people to interact. Plants were grown in these spaces to provide food near where people lived. Large open areas were used to create peaceful settings that showed power and wealth, especially for French leaders. These areas included gardens and paths lined with trees, which helped keep the air clean for wealthy people while keeping them separated from poorer citizens.

French city planners focused on making cities green by blending nature with urban design. They created spaces where people could live alongside nature, showing how the French valued natural areas as part of their growth.

In the 18th century, French citizens asked to remove old city walls to make room for new gardens and green walkways. This added more green spaces to cities. Town halls and city centers were decorated with trees and rare plants from other countries. This helped make cities look more beautiful and impressive.

In 1847, George Perkins Marsh spoke about the harm caused by cutting down forests. He later wrote a book called Man and Nature in 1864, which promoted forest conservation. Around the same time, Henry David Thoreau wrote Walden in 1854, which encouraged protecting nature and using it in city planning. Frederick Law Olmsted, a landscape architect, supported these ideas and designed parks and scenic roads. In 1887, he created the Emerald Necklace in Boston, a system of connected parks that helps protect wildlife and manage water.

In Europe, Ebenezer Howard started the garden city movement to balance urban development with nature. He designed cities with green areas and wide, tree-lined streets in England. His idea of combining towns and countryside helped create sustainable communities.

In the late 1800s, the U.S. government began protecting land and nature. This started with the 1864 law to preserve Yosemite Valley as a public park. Eight years later, the first national park in the United States was created.

In the 19th century, industrial leaders wanted to improve workers’ lives by providing clean environments and outdoor spaces. This idea continued into the 20th century, leading to efforts like green spaces in industrial areas, well-planned landscapes, and suburban gardens.

The Anaconda Copper Mining Company caused environmental damage in Montana. However, a refinery in Great Falls used the land around it to create a green space for recreation. This area included a golf course, flower beds, picnic spots, a pond, and walking paths.

The role of water: blue spaces and blue infrastructure

Water has played an important role in where people have lived throughout history. Being near water sources helps with transportation, trade, and producing energy. Water also provides resources such as drinking water, food, and opportunities for activities like recreation and tourism. Many of the world's largest cities are located close to rivers, lakes, or oceans. Cities have built water-related structures, such as canals and harbors, to use the benefits of water while reducing risks. However, cities face challenges like floods, droughts, and changes in water levels on rivers that cross borders. As cities grow quickly, many water-related structures are no longer visible. Coastal areas are becoming more populated, and many cities have changed how they use waterways like canals and docks because of changes in global trade. Scientists have recently studied how improvements to water areas near cities can affect people's health. A study from 2017 found that being near water areas is linked to better mental health and more physical activity.

One-fifth of the world’s population, or about 1.2 billion people, live in places where water is scarce. Climate change and water-related disasters will increase the need for water in cities and cause more people to move to urban areas. Cities use a lot of fresh water and have a major impact on water systems. Water use in cities and industry is expected to double by 2050. In 2010, the United Nations stated that access to clean water and sanitation is a basic human right. Scientists and planners are looking for new ways to make cities more sustainable. Managing water in cities is complex and requires not only systems for water and waste, but also ways to control pollution and prevent flooding. It also needs cooperation between different groups and governments to use water resources in a fair and lasting way.

Types of green infrastructure

Urban forests are forests found in cities. They are an important part of city green systems. Urban forests use tree and plant species that are not harmful or invasive, which reduces the need for maintenance and watering. Native plants also look nice and lower costs. Designing urban forests with a variety of plant species helps avoid planting only one type of plant. This makes the forests stronger and better at resisting pests and damage.

• Energy use: A study by the Lawrence Berkeley National Laboratory and Sacramento Municipal Utility District found that shade trees planted near homes can save up to 47% of energy used for heating and cooling.
• Urban heat island mitigation: Tree-covered areas have lower air temperatures than open areas without trees. This happens because trees cool the air through water evaporation from their leaves, block sunlight with their canopies, and increase air movement to help cool the environment.
• Water management: Urban forests help manage city water by capturing rainfall before it flows into water channels. Trees catch a lot of rainwater that lands on them.
• Property values: Adding more trees and greenery in cities can increase the value of nearby homes and businesses.
• Public health: Green spaces in cities improve mental health and well-being. Urban forests reduce the effects of heat islands caused by city materials, which harm health. Trees provide natural shade at a lower cost than artificial structures. Green spaces also help ecosystems become more stable, as seen in traditional Japanese farming. Green infrastructure can create jobs in cities and support environmental goals like those in the 1992 Rio Declaration on Environment and Development.

Constructed wetlands are manmade wetlands that act as natural filters. They include wetland plants and are built on land or floodplains to avoid harming natural wetlands. There are two types: subsurface flow systems and free water surface systems. Proper planning and care help prevent damage from changing water patterns or introducing harmful plants.

• Water efficiency: Constructed wetlands copy natural wetlands to improve water quality and use. They use plants, soil, and microorganisms to trap dirt, slow water flow, and break down pollutants.
• Cost-effective: Wetlands are inexpensive to operate and maintain. They help manage water levels and add greenery to their surroundings. They also reduce unpleasant smells from wastewater.

Green roofs improve air and water quality while lowering energy costs. In some areas, green roofs increase the ability to reflect sunlight, leading to cooler temperatures and less energy use. Plants and soil on green roofs add insulation and help reduce stormwater runoff in cities. Green and blue roofs also support rooftop farming for residents.

Green roofs capture rainwater and carbon pollution. Up to 40% to 80% of rain that falls on green roofs is stored. Water flows slowly from green roofs, reducing the amount of runoff that enters water systems at once.

Blue roofs collect and store rainwater, reducing the sudden flow of water into sewers. They use ponds or basins to hold rainwater before releasing it slowly into sewers and waterways. Blue roofs also lower cooling costs and reduce heat in cities when paired with reflective roofing materials.

Rain gardens are shallow, planted areas that collect rainwater from rooftops or roads. They allow stormwater to soak into the ground slowly.

Regular lawn grass does not control runoff effectively, so alternatives are needed. Rain gardens can reduce residential runoff by 30%. A typical rain garden for a home is 150 to 300 square feet. Costs range from $5 to $25 per square foot, depending on plant types and property slope. Native plants from wetland and river areas are best for cleaning runoff.

Stormwater basins collect rainwater in vegetated areas to reduce runoff, prevent erosion, filter water, and stop flooding. Newer designs use more plants instead of mowed grass for better results. These basins, called bioretention basins, are good at removing pollutants and absorbing dirt. Stormwater basins are part of the sponge city concept for managing floods.

Downspout disconnection is a green method that separates roof water from sewers, directing it to permeable surfaces. It helps reduce sewer overflows in cities with combined sewer systems. During heavy rain, downspouts can send 12 gallons of water per minute into sewers, increasing risks of backups. Some cities, like Milwaukee, require downspout disconnection to reduce water entering sewers.

Bioswales are stormwater systems that replace traditional sewers. Like rain gardens, they are planted channels in urban areas. They absorb or carry stormwater runoff.

Planning approach

The Green Infrastructure approach studies the natural environment to understand its functions and then creates rules or planning policies to protect important natural areas. If certain natural functions are missing, plans may suggest ways to improve them using landscaping or engineering.

In cities, this can mean reintroducing natural waterways and making a city self-sustaining, especially with water. For example, cities can collect water locally, reuse it, and include stormwater management in everyday infrastructure.

This approach has multiple uses, which helps use land efficiently and sustainably. In a crowded country like England, where land is under pressure, this is especially important. For example, an urban river floodplain can store floodwater, act as a nature reserve, provide green space for recreation, and support farming through grazing. There is growing evidence that the natural environment improves human health.

In the United Kingdom, Green Infrastructure planning is now included in national, regional, and local planning documents. For example, it is part of the Milton Keynes and South Midlands Growth area plan.

In 2009, Natural England published guidance on Green Infrastructure planning. This guidance highlights the importance of Green Infrastructure in "place-making," which means recognizing and preserving the unique character of a place, especially when new developments are planned.

In North West England, the former Regional Spatial Strategy included a Green Infrastructure Policy (EM3) and other references to the concept in land use policies. This policy was supported by the North West Green Infrastructure Guide. The Green Infrastructure Think Tank (GrITT) helps develop policies in the region and manages a website that shares information about Green Infrastructure.

The Natural Economy Northwest program supported projects led by The Mersey Forest to study the value of Green Infrastructure in the region. These projects looked at the economic benefits of Green Infrastructure, how it connects with traditional infrastructure, and where it can help solve problems like flooding or poor air quality.

In March 2011, a prototype Green Infrastructure Valuation Toolkit was introduced. This Toolkit, available under a Creative Commons license, includes tools to measure the economic value of Green Infrastructure projects. It has been tested in areas like the Liverpool Green Infrastructure Strategy.

In 2012, the Greater London Authority released the All London Green Grid Supplementary Planning Guidance (ALGG SPG). This guidance proposes an integrated network of green spaces and waterways. The ALGG SPG aims to promote Green Infrastructure and encourage its use by boroughs, developers, and communities to support sustainable travel, flood management, health, and economic and social benefits.

Green Infrastructure is being promoted as a way to address climate change challenges.

Green Infrastructure may include goals related to geodiversity.

In the United States, Green Infrastructure programs managed by the EPA and partners aim to improve water quality by managing stormwater runoff more effectively. These practices are expected to reduce pressure on traditional drainage systems, such as storm sewers and combined sewers, which are networks of underground pipes and surface water channels in cities. Improved stormwater management is expected to reduce overflows, reduce urban flooding, and provide other environmental benefits.

Although Green Infrastructure is not yet widely used, many U.S. cities have started using it to meet MS4 permit requirements. Cities do this by creating programs that offer incentives for private property owners to adopt Green Infrastructure or landscaping projects. There are about 555 such programs in the United States. For example, Philadelphia has installed or supported projects like permeable pavements in parks, rain gardens at schools, and constructed wetlands for stormwater management. These projects help reduce runoff entering the city’s combined sewer system, which lowers the risk of overflows during rainstorms.

Another example is Maryland’s "GreenPrint" program, which is a web-based map showing the ecological importance of every parcel of land in the state. GreenPrint Maryland uses maps, aerial photography, and environmental science to help protect critical lands and support sustainable growth. The program began in 2001 with the goal of preserving lands vital to protecting the state’s natural resources.

In April 2011, the EPA announced a Strategic Agenda to protect water and build more livable communities through Green Infrastructure. The first ten communities selected as partners included Austin, Texas; Chelsea, Massachusetts; Cleveland, Ohio; Denver, Colorado; Jacksonville, Florida; Kansas City, Missouri; Los Angeles, California; Puyallup, Washington; Onondaga County and Syracuse, New York; and Washington, D.C.

The Federal Emergency Management Agency (FEMA) also supports Green Infrastructure as a way to manage urban flooding.

Since 2009, Singapore’s Public Utilities Board has published two editions of the ABC (Active, Beautiful, Clean) Waters Design Guidelines. The 2011 version includes planning and design ideas for integrating drains, canals, and reservoirs with the environment. The Public Utilities Board encourages landowners, developers, and communities to use ABC Waters features in their projects for recreation and education.

The main benefits of the ABC Waters Concept include:
– Treating stormwater naturally near its source using plants and soil to clean water before it enters waterways and reservoirs.
– Improving biodiversity and making areas more visually appealing.
– Bringing people closer to water and creating spaces for recreation and learning.

Examples

A good example of green infrastructure used on a large scale is the Beijing Olympic site. First built for the 2008 Summer Olympics and later used for the 2022 Winter Olympics, the site is located in the northern part of the city between the 4th and 5th ring roads. It covers an area that was once an old industrial site that has been cleaned up and reused. The main green feature is the "Dragon-shaped river," a system of water basins and wetlands covering more than 500,000 square meters. From above, this system looks like a traditional Chinese dragon.

This system helps reduce pollution in water by filtering nutrients from nearby wastewater treatment plants.

Farmers once claimed that their farmlands flooded because of development upstream. The flooding happened because rainwater from hard surfaces, like roads and buildings, ran directly into storm drains and flowed into their fields. The farmers received an undisclosed amount of money in the tens of millions as compensation. Areas with low-density housing and many paved surfaces send stormwater into streams faster than before development. These practices harm the environment and are expensive to maintain. To address this, the city of Surrey, Canada, used green infrastructure at a 250-hectare site called East Clayton. This approach reduced the amount of stormwater flowing downstream and allowed rainwater to soak into the ground near where it fell. The system could hold one inch of rain per day, covering 90% of the yearly rainfall. This helped save about $12,000 per household.

The former factory site of Nya Krokslätt is located between a mountain and a stream. Danish engineers designed a plan to slow and guide stormwater using plants, ponds, streams, and soak pits. Green and blue areas around buildings help delay and clean water from roofs and greywater. This design creates a city space that includes energy-efficient buildings and green-blue infrastructure to support nature.

Since 1991, the city of Zürich, Switzerland, has required green roofs on flat buildings (except those used as terraces). This policy increases plant life, stores rainwater, and helps manage temperature extremes. Green roofs act as stepping stones for plants, connecting with natural areas and supporting biodiversity.

In Germany’s Ruhr District, Duisburg-Nord is a park that includes old industrial buildings and natural areas. The water park uses the old River Emscher, divided into five sections: Klarwasserkanal, Emschergraben, Emscherrinne, Emscherschlucht, and Emscherbach. Rainwater is collected and slowly added to the old river, keeping water levels stable even during dry periods. This allows nature to grow and provides space for recreation. Overgrown areas were kept to support plant and animal life, including species at risk. The plan also made the water system visible to help people connect with it.

The Greenhouse Project began in 2008 when parents and teachers wanted to teach children about food, the environment, and sustainability. Greenhouses are built on school rooftops and include hydroponic farms, solar panels, rainwater collection, weather stations, and composting systems. Lessons cover topics like nutrition, water use, climate change, and waste management. Students learn how humans and nature are connected and how sustainable practices support cultural diversity.

In the 1990s, Hammarby Sjöstad in Stockholm was a polluted and run-down area. Now, it is a model for sustainability. The Hammarby Model uses waste heat from wastewater to warm buildings, treats rainwater to return it to nature, and recycles sludge as fertilizer. This system inspires projects in cities like Toronto and China.

The U.S. Environmental Protection Agency (EPA) helped Emeryville, California, create "Stormwater Guidelines for Green, Dense Redevelopment." Emeryville, near San Francisco, cleaned up old industrial areas in the 1990s, boosting the economy. In the 2000s, the city required green infrastructure in new developments to manage stormwater. Challenges included high water tables, clay soils, and limited natural areas. Guidelines and tools were created to use redevelopment sites for stormwater management. Strategies included reducing parking space, using shared parking, promoting public transit, and requiring bicycle parking.

Geographic information system applications

A geographic information system (GIS) is a computer tool that helps people collect, keep, show, and study different types of information about Earth's surface. GIS can combine many types of data, such as roads, buildings, soil kinds, and plants, onto one map. Planners use GIS to mix or calculate useful details, like the percentage of hard surfaces or how much green space is in a certain area, to help plan or study green infrastructure projects. These systems can also use public participation GIS (PPGIS) to add information from people, along with traditional data, to better understand specific situations. As GIS technology improves and is used more often, it becomes very important for creating Green Infrastructure plans. These plans often rely on GIS to study many layers of information about an area. When planning urban green projects, GIS is increasingly used with methods from many fields, such as social, environmental, and cultural studies, to help planners make better decisions that consider all important factors.

According to the "Green Infrastructure Master Plan" created by Hawkins Partners, civil engineers use GIS to study maps of hard surfaces and compare them with past rainfall data in Nashville’s combined sewer system. This helps them find how much water runs off the land now. GIS can also help planning teams see how much water could be reduced in certain areas using green infrastructure, such as rainwater collection systems, green roofs, city trees, and structures that control water flow.

Implementation

Not having enough money is often a problem when trying to build green infrastructure. However, green infrastructure projects can help get money from many different sources. Some tax incentive programs run by the federal government can help attract funding for these projects. Here are two examples of programs that support green infrastructure:

• The U.S. Department of Energy manages energy efficiency tax incentives. Green infrastructure can be part of project designs to qualify for these incentives. For example, in Eugene, Oregon, a new biofuel station built on an old gas station site included a green roof, bioswales, and rain gardens. In this case, nearly $250,000 in tax credits helped reduce income and sales taxes for the private company that built the project.
• The U.S. Department of Treasury runs the New Markets Tax Credit Program, which encourages private investment for projects in areas that need help. This program gives tax benefits to non-profit and private groups based on their plans for using these benefits.

Some people might think green spaces are expensive and hard to maintain, but well-designed green spaces can provide real economic, environmental, and social benefits. For example:

• Trees in cities can help manage stormwater and reduce energy costs and runoff.
• Bioretention systems can be used to create green transportation systems.
• Lawn grass is not a good solution for runoff, so alternatives like rain gardens are needed. In homes, rain gardens can reduce runoff by about 30%. A typical size for a rain garden on a private property is between 150 and 300 square feet. The cost per square foot is about $5–$25, depending on the plants used and the slope of the land. Native trees, shrubs, and wetland plants are best for reducing runoff pollution.

Well-designed green spaces help balance built and natural environments. More green space in neighborhoods has been linked to more physical activity among older men and better mental health for people living near green areas.

Studies also show that people value the look and feel of green infrastructure. This means that green projects should focus on making spaces beautiful and meaningful to communities. A 2012 study of 479 green infrastructure projects in the U.S. found that 44% of these projects saved money, compared to 31% that increased costs. The biggest savings came from reducing stormwater runoff and lowering heating and cooling costs. Green infrastructure is often cheaper than traditional water management methods. For example, Philadelphia’s green infrastructure plan would cost $1.2 billion over 25 years, compared to $6 billion for a traditional plan using concrete tunnels.

Philadelphia’s green plan is expected to:
• Create 250 green jobs each year.
• Avoid or absorb up to 1.5 billion pounds of carbon dioxide yearly (equal to removing about 3,400 cars from roads).
• Improve air quality through trees, green roofs, and parks.
• Help communities with health and social benefits.
• Prevent about 20 asthma-related deaths and reduce missed work or school days by 250.
• Reduce deaths from extreme heat by 250 over 20 years.
• Increase property values by $390 million over 45 years, which also raises city property taxes.

In New York City, a green infrastructure plan would save $1.5 billion compared to a traditional plan. Green stormwater systems alone would save $1 billion, costing about $0.15 less per gallon. Over 20 years, the benefits in New York City would range from $139–$418 million. Each fully vegetated acre of green infrastructure is expected to provide $8.522 in energy savings, $166 in reduced carbon emissions, $1,044 in better air quality, and $4,725 in higher property values.

A 2016 study in the United Kingdom found that residents are more willing to pay for green infrastructure that is clearly visible, accessible, and serves many purposes. This suggests that designing green spaces to be both functional and attractive can increase their value to communities.

In cities like Chicago, green projects aim to improve the environment and quality of life, but they can also create social issues like gentrification. This happens when green spaces in low-income areas raise property values, pushing out current residents. Studies show that these projects often improve air quality and reduce heat but mainly benefit wealthier, whiter neighborhoods. In Los Angeles, research found that green infrastructure can increase the gap in green space quality and housing prices for minority communities, leading to "green climate gentrification." The effects of gentrification depend on the community and the types of infrastructure built, such as parks and transportation systems.