Carbon sinks and human freshwater dependence in Stockholm County

People living in cities depend on the capacity of ecosystems to sustain their welfare. However, many services provided by ecosystems for city life are not perceived by people and policy. The city of Stockholm is growing and in that process natural capital is replaced by human-made capital. To visualize the dependence on natural capital of citizens in Stockholm County, we estimate the ecosystem areas required for accumulating the total emissions of CO2 by the county’s population. Stockholm County is inhabited by 1.8 million people and covers an area of ≈7240 km2. Our results indicate that about 20170 km2 of forest-, wetland- and lake-area is required to accumulate the CO2 emissions of the population in Stockholm County. The Stockholm County ecosystems can potentially accumulate about 41% of the CO2 generated by traffic and about 17% of total anthropogenic CO2. We also estimate the amount of freshwater required to uphold a continued generation of ecosystem services in the county (green water). The ecosystems within Stockholm County require about 2.2 km3 of green water per year to sustain the flow of ecosystem services, which is about nine times the direct human use of freshwater in households and industry (blue water). The potentially appropriated ecosystem area, if total CO2 emissions from the population in Stockholm County were to be accumulated, would need more than 40 times the human blue-water appropriation. The green water appropriated by the ecosystems in Stockholm County is also indirectly appropriated by the human population through their dependence on ecosystem services. We discuss the usefulness and limitations of our approach in relation to focusing on people’s dependence on functioning ecosystems for ecosystem service generation and in structuring guidelines for management of these ecosystems.

Keywords: Carbon sinks, ecosystem services, Freshwater flows, Urban ecosystems

Jansson, Å., and P.Nohrstedt. 2001. Carbon sinks and human freshwater dependence in Stockholm County. Ecological Economics 39:361-370.