As designers, planners, and citizens, it is important to understand how our choices impact CO2 output, and in turn contribute to greenhouse gases. Is there less environmental impact, in terms of CO2 emissions, in renovating an existing building than building a new structure?
Adaptive reuse or renovation of an existing structure can be a good environmentally-conscious choice, resulting in as little as 10% of the environmental impact as compared to demolishing an existing structure and building anew.1 But interestingly, the worst choice by far can be leaving the existing building as is, continuing its status as an energy hog. A UK study did the math, measuring the CO2 output of the basic footprint of a two-bedroom cottage over the time period of 100 years.2 The study found that knocking down an old cottage and starting from scratch cost about 80 metric tons of CO2 (equivalent to 24 economy class flights from London to Hong Kong). The winning option, with a cost of only 8 metric tons of CO2, was to invest in higher levels of energy efficiency in the renovation of the existing home.
So, scout out those buildings and communities that have much life left to give, imagine new possibilities, and continue to dance lightly on the planet.