Environmental
Urban scale climate change, such as that encountered by Urban Heat Islands has numerous environmental system impacts. One of the greatest considerations is how the environmental system is impacted when increased electricity demand is required due to higher temperatures. The result is increased greenhouse gas emissions from traditional thermoelectric power plans such as coal power plants.
Energy systems are also impacted. Researchers at the National Center of Excellence at Arizona State University determined that in the Phoenix, Arizona metropolitan region, Urban Climate Change has resulted in a 10% demand increase in electricity. The DOE Lawerence Berkeley National Laboratories have estimated that every 0.1 increase in solar reflectance would decrease surface temperatures by 7oF (4oC).
Depending on the fuel mix, decreased energy demand will result in lower associated air pollution and greenhouse gas emissions. Cooler air temperatures also slow the rate of ground level ozone formation and could reduce evaporative emissions from vehicles.
For example, a 2007 paper estimated that increasing the albedo of pavement in cities world-wide, from an average of 0.35 to 0.39, could achieve reductions in global carbon dioxide (CO2) emissions worth about $400 billion.
Surface water and receiving water bodies are impacted due to “thermal shock.” During storm events, stormwater contacts urban surfaces including pavements that can have temperatures as high as 155F. The contacted water then transfers through engineered and natural conveyance systems and enters into water bodies such as lakes and streams. This sudden thermal shock has been shown to increase aquatic mortality.
