Lisbon prepares for extreme heat and torrential rain

In the grip of freezing temperatures now, Lisbon planners are all too well aware how things will change.

The council is today (Friday) presenting its ‘adaption strategy’ to the challenges posed by climate change.

According to Diário de Notícias, the document “will influence urban planning” from now onwards, and is available for public consultation for the all-too-brief period of 10 days (until January 30).

Principal risks set out in EMAAC – the municipal strategy to adapt to the climatic alterations of Lisbon – include more prolonged heatwaves in the summer, and “five times the number of torrential rains”.

Investigator Luís Dias explains that EMAAC’s research as part of the Climadapt project indicates that episodes of extreme precipitation, with around 120 mm of rain falling in 24 hours – and which used to come round every 100 years – will start being experienced every 20 years “from the middle of this century”.

Dias’ team at the University of Lisbon has therefore come up with a strategy that is likely to be adopted by the other 25 municipalities that took part in the project and basically recommends the creation of more green spaces and areas for water retention, which would serve to absorb increased rainfall and stop it accumulating, and also cater for river-overflow in the event of rising sea levels.

Two drainage tunnels, between Monsanto and Santa Apolonia, and between Chelas and Beato, are already part of the capital’s €170 million Drainage Plan – due to be completed in 2030 – though Energy and Green Spaces chief José Sá Fernandes has pledged that in “three or four years” work already underway should “minimise” the effects of intense rain on the capital.

As for the increase in the number of heatwaves – due to triple over the next 30 years – new green spaces promoting biodiversity should also “combat heat concentration” while EMAAC plans to use aerial photography to ‘map radiation patterns’ across the capital and elaborate a masterplan for more controlled and “thermically comfortable” new constructions.

In contrast to a recent report on Lisbon’s ‘earthquake risks (click here)’, EMAAC appears not to have listed these in relation to changes in weather patterns.

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