COOL: The cooling effect of urban vegetation in relation to plant water use and water availability during heat waves and drought events
Short description
Summers in southern Sweden in particular are expected to become warmer and drier as the climate changes. This means longer and more intense periods of heat waves, drought, and water shortages—societal challenges that require new solutions. Trees and other vegetation have a cooling effect both during the day and at night in built-up areas, and in order to utilize the potential of greenery, good access to water is required. This project investigates the cooling efficiency of different plants in different types of buildings and in relation to water consumption and water availability.
Water availability and consumption in warm environments
Access to water is often limited in relatively warm and dry built-up environments as a result of the large amount of built-up and paved surfaces that quickly drain water away and prevent infiltration and long-term storage of soil and groundwater. Some plants have adapted well to these conditions and continue to provide ecosystem services even during periods of increased climate stress. However, there are many species that respond to stress by reducing their water consumption, sometimes by shedding leaves, which leads to a significant reduction in cooling and shade when these are most needed to create a pleasant environment for city dwellers.
How this research is conducted
The cooling efficiency of urban vegetation in different types of buildings will be calculated using an urban energy and water balance model. This model will be linked to a surface water and groundwater model to analyze how water availability affects the cooling efficiency of vegetation during periods of heat and drought and how various surface water and groundwater measures (e.g., delaying and diverting surface water, infiltration and pumping of groundwater to urban vegetation) can increase water availability for plants and thus the cooling effect.
Research results
The results of the research are expected to contribute to better assessment of the ability of various green solutions to cool their surroundings based on the specific conditions and water availability of the location. The project will also contribute knowledge about how various measures can increase the amount of water available to plants during periods of heat and water stress. The study will also develop recommendations and tools for selecting the most appropriate green measures from a climate adaptation and sustainability perspective.
Expertise in the research project
The project is being carried out by researchers with expertise in urban climate, plant physiology, soil science, hydrology, and hydrogeology from the University of Gothenburg and Lund University. An important part of the study is input from local, regional, and national actors in the planning, establishment, and operation of green solutions and climate adaptation measures.