Heeft landgebruik effect op ons weer? : Literatuuronderzoek relatie landgebruik en klimaat op regionale en lokale schaal: De Kleine Waterkringloop

Climate change, caused by an increase in anthropogenic emissions of greenhouse gasses, is having an increasingly noticeable effect on the Netherlands. Over the past years, we have seen periods of extreme droughts and high temperatures, but also periods of heavy rainfall. It is expected that these extreme events will continue to increase in the future. In addition to global mitigation efforts, it is necessary to take measures to adapt to the negative consequences of climate change. Many ongoing and large-scale spatial redevelopment initiatives, including the Nationaal Programma Landelijk Gebied (NPLG), the Programmatische Aanpak Grote Wateren (PAGW), the Programma NOVEX, Provinciale Bossenstrategieën and the Programma Waterveiligheid en Ruimte Limburg (WRL), consider climate-adaptive planning as a major theme in their planning. However, these policies do not consider the more direct way in which land use and spatial planning can influence the climate: through alternating land-atmosphere interactions and the so-called small water cycle. Yet, the exact role of how this mechanism affect the local climate remains uncertain. Therefore, a coalition of Limburg-based parties (including the Natuur en Milieufederatie Limburg, Waterschap Limburg, RVO, Provincie Limburg and the Limburgse Voedselbosbrigade) argues that there is an urgent need for more research into these land-atmosphere interactions on a regional scale. In this research, a first step has been taken in the form of an overview of the current state of knowledge on land-atmosphere interaction in the Netherlands and North-western Europe, including the possibility to influence these interactions on a regional or local scale through choices in land use, land cover, water management and planning. Based on this, we can provide well-founded advice on the scientific and societal relevance of further (model) research on these interactions in the context of climate adaptation. Based on a bibliographic database of relevant scientific literature, consisting of 338 sources, we can formulate the following conclusions: • Land use can influence the local and regional climate through changes in albedo, evaporation and surface roughness, affecting energy distribution at the Earth’s surface, the depth and temperature of the atmospheric boundary layer, cloud formation, and precipitation. • Reforestation in the Netherlands leads to an increased precipitation, especially in the winter. Unlike many other locations on Earth, this precipitation in not formed by increased evaporation and convection, but rather seems to be created by capturing moist air due to increased surface roughness. • Urbanisation increases local and downwind precipitation due to an increase in sensible heat flux, surface roughness, and aerosols. • Changes within land use types, including transitions from deciduous to coniferous forests, plantations, forest management and increasing vegetation in cities, can also affect the local climate. • The ultimate (negative) effect of land use changes on the local and non-local water availability remains unclear. This literature review provides an overview of the current state of knowledge on land-atmosphere interactions and highlights the potential importance of the small water cycle on the water availability. Further research can be used to expand this knowledge towards specific policy-related issues. To adapt the Netherlands to the negative effect of global climate change, further model research on this subject is of both societal and scientific importance.