To realise the Net Zero Cities utopia we need to skip the dirty steps

Posted on Tuesday 25th January 2022

Are net zero cities achievable? What does this even mean? Lucelia Rodrigues has worked in sustainability for almost two decades and considers these questions in her latest blog.

Let’s talk about the ‘net zero’ concept by going back to basics. Global warming is the rise in global mean temperature due to rising greenhouse gases emissions. Climate change is a general term for the changes that happen in response to global warming. In 2018, the United Nations’ Intergovernmental Panel on Climate Change stated that unless we significantly reduce greenhouse gas emissions, there will be further and significant rises in global temperatures with hugely damaging consequences for the planet.

The greenhouse gases emissions that we must reduce include carbon dioxide, methane, nitrous oxide, and other gases that form the insulation layer that keeps Earth liveable. Greenhouse gases are actually essential to keep our planet at a suitable temperature for life – without them Earth would be too cold. But balance is key. Too much gas insulating our planet leads to too much heat being trapped, or global warming.

According to Our World in Data, 73.2% of human greenhouse gases emissions in 2020 came from energy. That includes energy used in industry (for example, to manufacture building components), in transport (for example, to transport building components and people from home to building sites) and in buildings (for example, to keep people comfortable and equipment running). And 74.4% of those gases are Carbon Dioxide (CO2), which is therefore the largest contributor to climate change.


We have finally arrived at the link between CO2 and the built environment, and you can see the complexity of the problem. CO2 is everywhere, released by almost all our activities – including the most basic, like eating and sheltering.

As humans need oxygen, cities need CO2 to stay alive. Therefore, delivering Net Zero Cities is a seriously wicked problem. A problem made even more indigestible due to its magnitude and timescales. Our individual carbon contribution may be in the atmosphere for thousands of years. And we cannot easily relate to that timeframe. That thought reminds me of the Hieroglyphic Stairway poem by Drew Dellinger “I’m awake because my great great grandchildren won’t let me sleep”. If only we were all awake..!!

Another issue is that we are organized to work within geographic boundaries, but climate change transcends not only geopolitical borders but also knowledge realms, and we humans are notoriously bad at working together. In order to deliver Net Zero Cities we will need to come out of our silos and work for the greater good, academics, politicians, businesses and the public #TogetherForOurPlanet.

Do we have the technology needed to go Net Zero? I believe we do. And I believe we don’t!

We have advanced low carbon renewable energy substantially in the last decade. We have invested in new energy storage technologies. We have developed new technologies, such as vehicle-to-grid and digital twin. We have created accurate carbon assessment methods. However, we still struggle to deliver these at cost, often forgetting about the embodied carbon implications of the things we build and the need to engage with a large part of the society who are key players if we want to make this work. We need to increase investment in science and focus on applying research to real world problems to deliver the much-needed societal impact.

In order to drive investment we need policies that give us no alternative but to do the right thing. Policies to enable, deploy and support low carbon alternatives that keep our cities alive. However, these policies need to be incremental, seeking continuous improvements to avoid plateaus. That means working backwards from cities going net zero carbon by 2050 and setting achievable targets along the way, particularly when it comes to the built environment where the need and support to achieve net zero carbon disappeared when the Code for Sustainable Homes was scrapped.

We’ve had the easy wins. Now we need to be bolder. Let’s skip the dirty steps, think beyond our subjects, work together.

  • Need more energy - Invest in reducing demand instead of new infrastructure.
  • Roads are congested - Invest in denser walkable neighbourhoods that attract services and therefore reduce the need to travel.
  • Buses are overcrowded - Invest in data technology that enables an understanding of where/when more resources or better mobility infrastructure are needed.
  • Shops are struggling - Invest in people not in malls.
  • Too much fossil fuel - Invest in infrastructure for electrification.

Skip the dirty steps.


Professor Lucelia Rodrigues
Chair in Sustainable & Resilient Cities
Tel: 0115 95 13176

Director of Transport, Mobility & Cities @ Nottingham
Deputy Director of University of Nottingham Energy InstituteCourse
Director of MArch in Architecture and Sustainable Design
Online profile | ORCID profile | Google Scholar profile | Twitter @luceliataranto

Further reading

Lucelia Rodrigues is a regular contributor to publications related to Architecture and the Built Environment. The latest are featured here.

MOHAMED, S., SMITH, R., RODRIGUES, L., OMER, S., CALAUTIT, J., 2021. The correlation of energy performance and building age in UK schools, Journal of Building Engineering, Volume 43, 2021, 103141, ISSN 2352-7102,

MOHAMED, S., RODRIGUES, L., OMER, S., CALAUTIT, J., 2021. Overheating and indoor air quality in primary schools in the UK, Energy and Buildings, Volume 250, 2021, ISSN 0378-7788, 111291.

ZUNE, M., TUBELO, R., RODRIGUES, L., GILLOTT, M., 2021. Improving building thermal performance through an integration of Passivhaus envelope and shading in a tropical climate, Energy and Buildings, Volume 253, 2021, 111521, ISSN 0378-7788,

SHIPMAN R, ROBERTS R, WALDRON J, RIMMER C, RODRIGUES L, GILLOTT M., 2021. Online Machine Learning of Available Capacity for Vehicle-to-Grid Services during the Coronavirus PandemicEnergies. 2021; 14(21):7176.

TUBELO, R.; RODRIGUES, L.; GILLOTT, M. ZUNE, M., 2021. Comfort within Budget: Assessing the Cost-Effectiveness of Envelope Improvements in Single-Family Affordable Housing”. Sustainability 202113, 3054.

TUBELO, R.; RODRIGUES, L.; GILLOTT, M., 2021. “Characterising Brazilian housing through an investigation of policies, architecture, and statistics”, The Journal of Architecture, 26:2, 191-211, DOI: 10.1080/13602365.2021.1895279

SHIPMAN, R., ROBERTS, R., WALDRON, J., NAYLOR, S., PINCHIN, J., RODRIGUES, L., GILLOTT, M., 2021. “We got the power: Predicting available capacity for vehicle-to-grid services using a deep recurrent neural network”, Energy, Volume 221, 2021, 119813, ISSN 0360-5442,


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