title: Effects of city expansion on heat stress under climate change conditions.
abstract: We examine the joint contribution of urban expansion and climate change on heat stress over the Sydney region. A Regional Climate Model was used to downscale present (1990-2009) and future (2040-2059) simulations from a Global Climate Model. The effects of urban surfaces on local temperature and vapor pressure were included. The role of urban expansion in modulating the climate change signal at local scales was investigated using a human heat-stress index combining temperature and vapor pressure. Urban expansion and climate change leads to increased risk of heat-stress conditions in the Sydney region, with substantially more frequent adverse conditions in urban areas. Impacts are particularly obvious in extreme values; daytime heat-stress impacts are more noticeable in the higher percentiles than in the mean values and the impact at night is more obvious in the lower percentiles than in the mean. Urban expansion enhances heat-stress increases due to climate change at night, but partly compensates its effects during the day. These differences are due to a stronger contribution from vapor pressure deficit during the day and from temperature increases during the night induced by urban surfaces. Our results highlight the inappropriateness of assessing human comfort determined using temperature changes alone and point to the likelihood that impacts of climate change assessed using models that lack urban surfaces probably underestimate future changes in terms of human comfort.
authors: Climate Change Research Centre, University of New South Wales, Sydney, Australia; ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney, Australia.
authors: Daniel
authors: D
authors: Argüeso
authors: Climate Change Research Centre, University of New South Wales, Sydney, Australia; ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney, Australia.
authors: Jason P
authors: JP
authors: Evans
authors: Climate Change Research Centre, University of New South Wales, Sydney, Australia; ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney, Australia.
authors: Andrew J
authors: AJ
authors: Pitman
authors: Climate Change Research Centre, University of New South Wales, Sydney, Australia.
authors: Alejandro
authors: A
authors: Di Luca
mesh_terms: D002947:Cities; D057231:Climate Change; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D014507:Urbanization