We Have a Legacy Buildings Challenge to Overcome in Our Fight to Mitigate Climate Change

For the past week my wife and I have been enjoying an escape from Toronto to the shores of Georgian Bay on Lake Huron. I have had a greater need to walk on the seemingly endless strand of sand that is Wasaga Beach. But a day of rain has given me pause and made me return to this blog with a topic that considers how governments need to alter existing policies related to climate change.

In a September 5th posting here I noted that 40% of climate-changing carbon emissions come from our built infrastructure. I further commented that retrofitting older structures would do more to reduce our emissions than all the carbon capture projects we build over the next decade and beyond.

A June 15th article in The Economist described how in Europe and the United Kingdom there has been a construction frenzy in urban settings with tall glass towers sprouting everywhere. And wherever there is a new tower, an old building comes down. The Economist article used the same number, 40%, in describing how this behaviour “could literally cost the Earth.” What The Economist noted is that building emissions include two things: pollution coming from operations (27%), and that which comes from embodied carbon expended in materials, maintenance, retrofits and rehabilitation, and demolition.

The Economist notes that buildings represent a growing carbon footprint expected to double by 2050. Why is this? Because of urban intensification more of us live in cities. Meanwhile, governments institute policies aimed at increasing population density in urban locations seen by most to be of benefit in addressing climate change mitigation and adaptation. The truth, however, is in the way most are executing the policy, it is proving counterproductive.

Energy efficiency is one of the reasons property developers want new structures to replace old ones. New structures comply with building codes that address new energy conservation standards like LEED. But today in Europe, according to The Economist, and likely in North America as well, “less than 1% of buildings are net-zero.”

When addressing embodied carbon contribution to global emissions from legacy construction, it is maintenance that produces the largest percentage. Legacy renovation and rehabilitation add more emissions in the short term to a building’s embodied carbon, but over the long term, because of energy conservation reduces its carbon footprint.

But where climate change policy decisions continue to clearly go wrong is in giving property developers the license to tear down old buildings and replace them with something new. The Economist calls this “the indestructible appeal of the wrecking ball.” In my home city, Toronto, construction cranes cover the skyline today. Old, energy-inefficient buildings come down, and new more energy-efficient ones arise.

But is anyone looking at the climate change impacts of this behaviour? Today, new construction uses almost all of the cement, half of the steel, and a quarter of the aluminum and plastic produced globally. Each one of these materials represents significant carbon emission producers. The European Union calculates that construction generates one-third of the continent’s waste. In the United Kingdom, building demolition and excavation contribute nearly two-thirds of all of the nation’s waste.

And the tax regimes in Europe, the United Kingdom, and North America favour property developers’ demolition behaviours. There are significant tax advantages in knocking down a building and replacing it rather than renovating and rehabilitating legacy structures. In the United States for example, where new construction receives considerable tax benefits, only buildings designated as having historical significance get equal consideration when rehabilitated. But the vast majority of legacy buildings don’t fall under the latter definition no matter how old.

The Economist notes the need to address a growing crisis brought on by:

1. World population growth will contribute to an ongoing demand for new housing which means the built environment needs to grow along with our global energy needs.
2. Construction in the fastest growing nations of the Global South, and places like China, will in thirty years make cities unrecognizable with 50% of what we see being new builds further contributing to global carbon emissions.

Without wholesale tax code revisions that favour rehabilitation and repurposing of legacy builds over demolition and new construction, we will be fighting a losing battle in our efforts to reduce global warming.