[Kenyan Chapter] Monitoring Change in Urban Green Areas and Tree Cover using Satellite Imagery

Challenge Background

Nairobi city is globally admired and even termed the Green City in the Sun.

Over the years, however, the urban heat island effect has come into force. This is partially attributed to increase in greenhouse gas emissions and a decrease in tree cover as urban encroachment into forested areas ensues. Having this in mind, developing a workflow that can enable us to monitor change in the urban green areas is paramount and promises to be of use to local government and policymakers that could take the results from this project to make cities like Nairobi more green and sustainable.

The Problem

Prosperous cities seek to increase their green areas for better air quality and improved quality of life for their populations. Green spaces in cities mitigate the effects of pollution and can reduce the urban heat island effect. At the same time, land use change in urban areas leads to a reduction in tree cover, contributing to the loss of biodiversity. Accordingly, it is important for cities to monitor their progress in maintaining and increasing their tree cover and green areas. The monitoring will enable city authorities to measure the environmental impacts of urban development against their mitigation measures, as well as support city policy actors in decision-making. 

Goal of the Project

The AI solution should involve the extraction of data from satellite imageries hosted on cloud-based platforms (e.g., the Earth Engine’s public data catalog), and within defined city boundaries, generate statistics on two urban indicators related to environmental sustainability. To enable comparison of city statistics, the project will utilize the urban boundaries generated through the harmonized city definition approach (JRC-UrbanCentresDatabase).

These indicators are:

• Change in green Areas per Capita as defined in the Global Urban Monitoring Framework (UMF-47). The methodology involves the estimation of a city area under vegetation cover for several time periods e.g., the year 2000, 2010, and 2020; the indicator has 2 key metrics: change in green areas over time, and change in per capita green areas over time, which factors the changes in city population.

• Change in Tree Cover as defined in the Global Urban Monitoring Framework (UMF-48). The methodology involves estimation of the city area under tree cover for several time periods e.g., the year 2000, 2010 and 2020, and analysing the change over time.

Project Timeline

What you'll learn