Cities and climate change: why low-rise buildings are the future – not skyscrapers

Synopsis: The plan of urban architecture for accommodating more people needs a change. The new research model offers solutions to both infrastructure and climate.

Introduction

More than 50% of the world’s population live in cities and urban areas. By 2050, an additional 2.5 billion will be living there.

Hence, we need a climate proof plan of architecture for urban areas.

There is a popular belief that taller, more densely packed skyscrapers are the way forward, because they optimise the use of space and house more people per square metre and limit urban sprawl.

But as per a new study and given the global commitments to emission-reduction targets and mitigating climate change, this is not the most sustainable solution from a carbon-reduction perspective.

The study found that densely built, low-rise environments are more space and carbon efficient, while high-rise buildings have a drastically higher carbon impact.

What was the study and its findings?

In the study, both operational and “embodied” carbon — of different buildings and urban environments were studied. Four different urban scenarios were developed:

High-density, high-rise (HDHR)- tall and close together.

low-density, high-rise (LDHR)- tall but more spread out.

high-density, low-rise (HDLR)- low and close together.

low-density, low-rise (LDLR)- low level and more spaced out.

Results: The study showed that HDLR scenario is more space and carbon efficient i.e more environmentally friendly.

When moving from a HDLR to HDHR urban environment, the average increase in whole life-cycle carbon (both operational and embodied) emissions is 142%.

Why building design is a critical element?

At a global scale, the construction sector is responsible for a significant impact on the environment. In this, largest contribution comes from ‘consumption of energy and resources’, which is due to design stage neglect.

Design is also important because skyscrapers rely heavily on concrete as a structural material. And concrete has highest hidden carbon contribution among construction materials. So the type of materials we use, how much we use, and how we use them is crucial.

What are the various issues with the present building design frameworks?

Presently, in building design, “operational efficiency” is given more importance, however “embodied impact assessment” is voluntary and therefore neglected. The focus is on driving down ‘operational energy’ requirement.

However the proportional share of ’embodied energy’ consumption has been driven up, as the materials and activities required to build it in first place produce proportionally more impacts across the building’s lifespan.

What is the solution?

We need to build more HDLR type buildings rather then HDHR.

Source: This post is based on the article “Cities and climate change: why low-rise buildings are the future – not skyscrapers” published in “Down To Earth” on 29th October 2021.