One means of quantifying natural resources is to use the concepts of Natural Capital and Ecosystem Services. Analogous to financial accounting, Natural Capital is the stock of environmental assets – land, air, water, species, habitats and ecosystems – that generates a flow of benefits, or ‘dividends’, to human beings in the form of Ecosystem Services – such as food, fuel, soil production, pollination, nutrient cycling and climate regulation. On one hand, some stocks and flows are simple quantities, such as the amount of forest present in an area of interest and the annual primary productivity associated with this forest. On the other hand, some flows can consist of complex processes, such as the coastal protection afforded by mangroves against floods and hurricanes, or water and nutrient cycling.
It is now widely acknowledged that we are currently experiencing unprecedented rates of global environmental change. These changes are threatening the Earth’s Natural Capital and its ability to provide goods and services today and into the future. Hence, maintaining the health and integrity of Natural Capital is central to safeguard future human well-being. However, Natural Capital cannot be managed or protected efficiently unless we know what stocks and flows are available, where they are distributed and how global environmental change is affecting them. Moreover, not only do we need a tool to accurately measure Natural Capital stocks and flows, but the assessment ideally needs to be performed at the global scale. This means that measures have to be repeatable and comparable between different regions of the world, but also transparent, verifiable and ideally performed relatively cheaply. Satellite-based remote sensing is a crucial tool in meeting those requirements.
This project, 'Monitoring Natural Capital from Space', makes use of freely-available remote sensing products, such as the Moderate Resolution Imaging Spectroradiometer (MODIS), Landsat and the Advanced Very High Resolution Radiometer (AVHRR) to quantify Natural Capital stocks and flows by, for example, deriving information on the structure of the environment and calculating vegetation indices like the Normalized Differenced Vegetation Index (NDVI) that serves as an indicator of the productivity and state of vegetation.
Using Kenya - a country known for its huge savannahs and mangroves which contain a high level of biodiversity - as a case study, we demonstrate in this initial report how 10 types of Natural Capital and Ecosystem Services can be measured from space at national and site level, using mainly freely-available remote sensing data.
For further information on this project, contact Dr Nathalie Pettorelli.