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Underground climate change is every major city’s ‘silent hazard’

As global temperatures increase, above-ground heatwaves shouldn’t be our only concern. Researchers are uncovering that urban cities are experiencing rising temperatures underground – and that’s a major long-term problem.

By now, we’re all well aware that atmospheric climate change and global warming are causing major issues for natural environments, wild animal species, and the safety of humanity itself.

But research conducted in Chicago has revealed that the ground beneath major cities is heating up to such high temperatures that it is slowly becoming deformed.

This phenomenon is linked to ‘subsurface urban heat islands,’ which are domes of heat that engulf densely-populated cities – especially when they have limited greenery, sparse open space, dark concrete surfaces, and are producers of high levels of emissions.

According to a team of scientists at Northwestern University, a wide majority of modern buildings will be unable to withstand unstable ground as the situation worsens.

This is because underground materials, including soils, rocks and concrete, warp when subjected to significant temperature variations.

Learning about underground climate change

Researchers at Northwestern University used Chicago as a ‘living laboratory’ to investigate the impact that underground temperature variations have on modern buildings and infrastructure.

They installed more than 150 temperature sensors both above and below ground in the Chicago Loop – in basements, subway tunnels and under Grant Park – to test their theory.

What they found was that underground temperatures in this loop are often 10 degrees Celsius warmer than those beneath Grant Park. Surrounding air temperatures were also affected by this underground warmth.

They could reach up to 25 degrees Celsius warmer compared to areas where ground temperatures were unchanged by human activity, such as the installation of subway systems and parking garages.

Northwestern professor Alessandro Rotta Loria said, ‘The ground is deforming as a result of temperature variations, and no existing civil structure or infrastructure is designed to withstand these variations.’

She continued, ‘Although this phenomenon is not necessarily dangerous for people’s safety, it will affect the normal day-to-day operations of foundation systems and civil infrastructure at large.’

This is not an isolated issue

The scientists at Northwestern pointed out that underground climate change is likely common in every dense urban city worldwide.

Where most cities today are becoming ‘subsurface urban heat islands,’ confirming whether they are experiencing underground climate change will need to be investigated on a ‘case by case basis’.

Though there’s no reason to panic immediately, it’s extremely important to understand how climate change driven by humanity activity isn’t just a surface-level issue.

As our environmental crisis continues to drive up the number of climate migrants who are forced to move away from coastal areas and inland to cities, urban areas will face increased pressure.

In tandem with reducing emissions and taking better care of our natural landscapes, architectural innovation will be vital in adapting to a world that is increasingly warming – above and below ground.