chinese train rail

Climate change threatens rail infrastructure, study finds

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Rising temperatures due to climate change threaten railway infrastructure, a study from Beijing Normal University has found.

Focusing on the Chinese rail system, the researchers believe that just half a degree Celsius less warming would save economic losses of approximately $630m (£452bn) per year.

The rainfall-induced disaster risk of railway infrastructure was shown to increase with rising extreme rainfall days during the decades 1981-2016.

Limiting global warming to the Paris Agreement target of 1.5°C instead of 2.0°C would significantly reduce the disaster susceptibility of Chinese railway infrastructure to extreme precipitation, according to Liu Kai, first author of the paper.

“Flood disaster can inundate the railway track [and] cause failures of the subgrade and track structure,” she said. “Based on our statistics, a total of 975 historical railway rainfall-induced disasters was reported from 1981 to 2016.

“The rainfall-induced debris flow had the largest contribution, about 42 per cent; followed by the rainfall-induced flood, which is about 26 per cent; rainfall-induced landslide, about 18 per cent, and rainfall-induced compound hazards, about 14 per cent.”

The team used a “random forest” machine-learning model to calculate the disaster susceptibility and quantify the relationship between susceptibility and precipitation change.

“We found a remarkable increase in the disaster susceptibility of railway lines along the Yangtze River valley, which is the economic centre of China with the largest population density,” said Liu. “The disaster susceptibility has increased by 30 per cent during the period 1999-2016 relative to that in 1981-1998.”

The proportion of railway infrastructure with high disaster susceptibility is projected to increase from the baseline period level (1981-1998) of 1.1 per cent to 4.5 per cent by 2050 and up to 12 per cent by 2090.

With a global average temperature increase of 1.5°C, the direct damage and repair cost is expected to increase to an annual amount of $1.47bn on average. With 2°C warming, the damage doubles and the loss grows to $2.10bn.

The Chinese railway system is still under large expansion with the total mileage of its railway lines expected to reach about 200,000km in 2035, compared to about 140,000km in 2020.

“The design of newly planned high-speed railway lines should incorporate climate change effects. How to reduce the disaster susceptibility of the world’s most densely populated railway network should be planned to limit the adverse impact,” Liu said.

Last year, the UK’s Network Rail had its budget cut by £1bn in the Chancellor’s Spending Review, despite recent commitments from the government to invest heavily in infrastructure.

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