Subway Systems Against Climate Change: Why Underground Transportation Wasn’t Built for This World

When the first tube trains began running in London in 1863, few could have imagined that climate change would one day test the very foundations of subway systems around the world. Today, from Washington, D.C. to Paris and Rome, subways are on the front lines of a battle they were never designed to handle.

Climate Underground

While the streets above ground battle heat waves and storms, underground tunnels are compounding the problem. Trapped heat creates stifling conditions, moisture breeds mold and floodwaters can turn stations into dangerous reservoirs. Passengers often describe the summer air in the subway as “an oven underground.”

The formula is simple:

Rising global temperatures + aging infrastructure = high health and financial risks.

Health at stake

Doctors warn that prolonged exposure to subterranean heat and polluted air can worsen respiratory and cardiovascular diseases. In Paris, studies have shown that particulate pollution levels in some stations are 3 to 5 times higher than at street level. For passengers with asthma or heart disease, every ride carries invisible risks.

Cities count the costs

Adapting aging subways doesn’t come cheap. The Washington, D.C., subway recently announced a nearly $500 million climate-resilience upgrade. In Rome, efforts to protect historic stations from flooding are estimated at $1.2 billion, while Paris has already allocated €2 billion ($2.2 billion) to adapt to climate change ahead of the 2024 Olympics.

Expert opinion

Urban climate experts say that while the metro is vital to reducing car use and emissions, it needs to be redesigned to take climate change into account. “Your metro wasn’t built for this world,” says Dr. Sophie Laurent, a climate resilience researcher in Paris. “But with bold investment, it can become part of the solution, not the problem.”

The way forward

Advanced ventilation systems to combat underground heat.

Smart pumps and barriers to combat flash floods.

Cleaner air circulation to protect passengers’ lungs.

The health of passengers – and the climate resilience of cities – depends on how quickly governments can act.