Carbon offsetting is becoming an excuse to build huge concrete buildings

It has been six months since COP26 in Glasgow and six months since I drove back down the M74 & M6 in my electric car with a warm fuzzy feeling that we would save the world. Since that bright November morning, much has changed: an unconscionable war in Ukraine, the end of pandemic restrictions, and an escalating fuel and cost of living crisis. In their own peculiar way, all of these issues have further underlined the grave topics discussed at the conference.

At COP26, I spoke with many like-minded people about the challenges we face. We discussed the problems the built environment posed to the world and how, with decisive action, our buildings could be part of a climate solution. However, as I took part in planning, design and construction meetings in the intervening months, I realised that the word offsetting was being used more and more frequently. This began to worry me.

To restrict temperature rise to 1.5 degrees, we would have to plant trees over an area five times the size of India

I fear that our reliance on offsetting prevents us from asking the right questions about how and where we should build. We cannot offset our way to net zero, that’s just not possible. We (the world) need to restrict carbon emissions to around 26 Giga Tones (GT) by 2050. We are currently set to produce approximately 56 GT of carbon by 2050. Now a tree absorbs about 25 kg of carbon per annum, so to offset enough carbon to restrict the end of century temperature rise to 1.5 degrees, some reports suggest we would have to plant trees over an area five times the size of India.

This clearly is not possible, so we have to stop offsetting, and we have to stop now. Of course, we need to plant more trees, but not as an excuse to build huge concrete buildings and ignore more sensible architectural options. Let's not forget that offsetting (in part) allowed Westminster Council to approve the demolition of the M&S building on Oxford Street. Without offsetting, it would have been impossible for the planners to ignore the almost 40,000 CO₂e footprint associated with demolishing this perfectly sound building and rebuilding in its place.

Instead of focusing on the lofty ideals of zero-carbon and on soundbites, we should simply focus on the carbon impact of the architectural intervention versus its overall benefit to society. I know this may sound counterintuitive, but my reasoning is sound because, in many cases, people only claim to have reached these lofty goals because of offsetting. In other words, because zero-carbon can be unrealistic in certain circumstances, we rely on offsetting.

It will not be easy and will almost certainly be imperfect; however, we need to develop a viability methodology that is independent, objective and focused on carbon impact versus social need. If we don't do this, the world will not reach its net-zero goal as any building could be argued to be sustainable through the mechanism of offsetting. So instead of demonising architects because they create structures, why don't we devise a system that honestly and precisely evaluates the carbon impact of a building against its benefit to society? Isn’t that a more helpful calculation?

At the moment, we are using offsetting as a tool to create buildings that are perhaps not as carbon efficient as they could be. The pressure from clients to be able to proclaim their building is ‘net-zero carbon’, ‘carbon positive’, and even ‘net zero life carbon’ puts architects under enormous pressure. If you have to offset to achieve these goals, then you quite clearly have not achieved them.

Let’s rid ourselves of these conceited phrases and instead focus on the real issues. We need new buildings, and these buildings will have a carbon footprint. However, does society’s need for the building outweigh its carbon impact? If the answer is yes, then let’s build as efficiently as possible without relying on offsetting.

Offsetting is not sustainable. In fact, it's not even close to being sustainable, and most worrying of all, it is allowing lazy, ego-driven designs to be accepted by us all. We must find an objective and fair way to assess if (and how) a building should be constructed. This is the only way the built environment can become part of the climate solution.