The Chicago heat wave of 1995 brought four scorching days to the city in which the heat index reached 120 degrees Fahrenheit. With the heat came power outages and buckling roads, which left residents stranded in the heat. In all, more than 700 people, mostly the elderly and ill, died due to heat-related causes.
This incident illustrates how heat can build up in major urban centers like Chicago; a phenomenon known as the urban heat island effect. Cities are usually hotter than their surrounding rural areas because all the buildings and pavement absorb the sun's heat during the day and keep giving off heat into the night.
In order to combat this, Chicago has taken a number of steps to "green" their city that will both bring down the temperature and save the city money in the future.
One of these steps is the city's green roof initiative, which encourages buildings to plant gardens on their roofs which soak up heat, and keep both the buildings underneath and the air above them cooler. That, in turn, reduces the cost of air conditioning. The green roof that covers Chicago's City Hall saves the building about $3,600 a year.
Beyond the green roofs, Chicago is also looking to green their alleys and streets by using materials like permeable paving stones and high-albedo pavement. The permeable pavers will allow excess rainwater to drain through the street and be soaked up by the ground below, helping to solve the city's flooding issue. High-albedo pavement (pavement that is lighter in color, and therefore more reflective) helps to prevent pavement from absorbing too much light and heat.
"If every rooftop in Chicago was covered with green roof, the city could save $100 million in energy every year, so there is a direct benefit between the amount of heat energy gained by a building that's not covered, or protected, by a green roof, and that does translate into cooling costs downstairs," - Jason Westrope, Development Management Associates.
1. What is a heat wave?
2. Why are temperatures hotter in a city than in a forest?
3. Which would you rather wear on a hot day, a white or black t-shirt? Why?
1. What was the most interesting thing about this report? Why?
2. What are some steps that everyone can take help the environment?
3. Have you seen any of the green ideas from the video in your community? If so, which ones? Which would work best?