UN Habitat: urban world, Volume 1, Issue 5

Smart Cities Start with Smart Buildings
By: Ron Dembo

Buildings are underplayed in terms of their contribution to emissions with nearly 40 percent of US emissions attributable to buildings compared to just 3 percent for four-wheel drive vehicles. Ron Dembo outlines how we must clad buildings to reduce emissions and why changing the occupants’ behaviour is key to tackling climate change.

The 2009 Copenhagen climate summit has made it clear that we require urgent action on climate change. Scientists calculate that we need to stabilize the concentration of carbon dioxide in the atmosphere at no more than 350 parts per million (ppm) to prevent runaway global warming and its potentially catastrophic impact on our civilization and the natural world as we know it. We are already at 390ppm, and adding to this at roughly two ppm a year.

In other words, we not only have to halt the increase in global carbon emissions, we have to turn the process around, and fast. We have to reduce global carbon emissions by 80 percent or more.

This will take an enormous effort on many fronts. When we look at the major sources of carbon emissions and where the efforts are currently directed, there is one area where we have scarcely scratched the surface, and that is our buildings.

Buildings are responsible for nearly 40 percent of energy consumption and carbon dioxide emissions in the US. Operating them consumes over 70 percent of all electricity generated in the region. The emissions rate is most intense in cities, with buildings responsible for 79 percent of New York’s carbon footprint, 73 percent of Hong Kong’s, and 52 percent of London’s carbon footprint. To put this in perspective, four-wheel drive vehicles count for just 3 percent of emissions in North America.

This comes as news to many people, including environmentalists. Buildings do not immediately come to mind when people think of carbon villains. The reason is that until recently we never measured things like the carbon emissions of buildings, or if we did we certainly never aggregated the measurements in any meaningful way. But once we know this information we cannot ignore it. If we are serious about tackling climate change, we have to do something about our buildings.

Retrofitting is not enough.

So far, the focus has been on new buildings. Hence we have the Leadership in Energy and Environmental Design (LEED) standard in North America, PassivHaus in Germany, Building Research Establishment Environmental Assessment Method (BREEAM) in the United Kingdom and others. These standards are important. They are helping create a new Climate change with the potential for significant energy savings.

I use the word “potential” deliberately, because it turns out that many of these buildings are not delivering the promised carbon reductions. This is because although the infrastructure of the building has been addressed, the culture of use has not – but more on this later.

Only a tiny proportion of our buildings are new and meet modern energy efficiency ratings. Most of our buildings are not only old, they are likely to be with us for a long time yet. For example, over 50 percent of nonresidential buildings in England and Wales were built before World War II. Most nonresidential buildings built anywhere since then are reinforced concrete structures with an expected life of 60 years or more. This presents us with a massive problem. We have to somehow reduce the carbon emissions of almost our entire building stock. We have to retrofit millions of buildings with energy efficiency measures. You can get a sense of the scale of the challenge if you go to the top of the Rockefeller Centre and look down the avenues of New York. We have to deal with all those buildings, keeping in mind that New York is just one city.

We have some ideas about how we need to tackle the problem. We know we need to insulate and draught proof. We know we need to fit low energy lighting and more efficient heating and cooling systems. A number of such projects are already under way, including a USD 175 million programme in Washington to retrofit 400 government and private buildings. But there are two problems with this approach. The Washington programme is aiming for 25 percent energy efficiency gains. This is a long way from the 80 percent reductions we need. The other issue is that with many of our older buildings it is the structure itself that is the problem.

Read the full article in PDF at: Smart_Cities_Report.pdf or online at: http://www.scribd.com/