CO2 produced by human activities is recognized as the main environmental disturbance of the Anthropocene, with dramatic consequences on the climate. There is therefore an urgent need to find innovative nature based solutions to reduce CO2 emissions and to find ways of storing it. Small water bodies, such as ponds, have recently been recognized as ecosystems playing a central role in the carbon cycle. Collectively, ponds trap as much carbon as the oceans. However, they can also produce large amounts of greenhouse gases.
In this project, we are, for the first time, investigating the CO2 sequestration potential of rooftop ponds. Indeed, urban areas are growing rapidly, offering countless new roof surfaces. These surfaces are often green (vegetation), but can also include blue elements (water). Our hypothesis is that rooftop water bodies, due to their elevated location, can effectively trap carbon. They are exposed to the wind, which promotes oxygenation and water mixing. In addition, rain, their only water source, is only lightly loaded with nutrients. These two characteristics are known to shift the carbon balance towards sequestration rather than emissions.
This project plans to study 40 ponds located on existing roofs in several large Swiss cities.
It is financed by the SNSF's SPARK programme and will run for one year (2021).
Project leader - team
Beat Oertli
(HEPIA),
Marine Decrey
(HEPIA)