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Listen to part of a lecture in an environmental science class. Professor: Today we're discussing the concept of 'urban heat islands.' As cities grow, they replace natural surfaces like soil and vegetation with asphalt, concrete, and buildings. These materials absorb and retain heat from the sun much more than natural landscapes do. During the day, buildings and roads soak up solar radiation, and at night, they release it slowly, keeping urban areas warmer than surrounding rural areas. This temperature difference can be significant—sometimes up to 5 to 10 degrees Celsius. There are several strategies to mitigate this effect. One is increasing green spaces, like parks and green roofs, which provide shade and cool the air through evapotranspiration. Another is using reflective materials on rooftops and pavements to bounce sunlight back into the atmosphere. Additionally, reducing vehicle emissions and promoting public transit can lower the waste heat generated by cars. Now, why is this important? Higher temperatures in cities lead to increased energy consumption for air conditioning, higher air pollution levels, and even heat-related health risks. So, addressing urban heat islands is crucial for sustainable urban planning.