Greenhouse gas regulation by wetlands

Abstract

Wetlands are unique and productive ecosystems that perform essential ecological functions. They cover only 6% of the earth's surface, yet they play a crucial role in maintenance and improvement of water quality; controlling soil erosion and floods, regulating the hydrological cycle and retention of nutrients and carbon. Wetlands also contribute to local climate regulation through distribution of incoming solar energy, by transferring solar energy from latent heat flux (cooling) into sensible heat flux (warming of air). The amount of water vapour, as a greenhouse gas, found in plant stands and in the atmosphere is many times higher than the amount of CO 2 and it changes dramatically across time and space. Water exists on the Earth in three phases and its transition between these phases is linked with uptake or release of high amounts of energy. The cooling effect of evapotranspiration is introduced in terms of solar energy and water vapour fluxes. The effect of wetlands on the daily dynamic of surface temperature is shown by thermographic and visible pictures of the mosaic of a cultural landscape with wetlands. We thus demonstrate that wetlands cool landscape and moderate daily extremes of temperature; in this way we seek to quantify the global role of wetlands in regulation of greenhouse gases and influence on local climate.