Why Barcelona’s rooftops could soon be painted white

Painting the rooftops of the Catalan capital could lower temperatures by up to five degrees, climate scientists say.

Why Barcelona's rooftops could soon be painted white
In 2020, Barcelona recorded its hottest year in 200 years. Scientists say painting roofs white could help lower temperatures. Photo by Josep LAGO / AFP

Barcelona’s terracotta rooftops have become as well-known as some of the city’s modernist buildings. In recent years, aerial photos taken with drones have highlighted the symmetry of the grid-like neighbourhood of the Eixample, as well as the earthy colour of the city’s buildings.

But the the way Barcelona looks from the sky could change in the near future in order to make the city more resistant to heatwaves.

Climate change researchers at the Universitat Autònoma de Barcelona (UAB) are leading a project to paint the city’s rooftops white to reduce temperatures.

A combination of painting rooftops and increasing green areas in the city from 32.5 per cent to 35.9 per cent could reduce temperatures by up to 4.7 degrees Celsius during heatwaves.

Urban building materials like concrete and brick store solar radiation throughout the day and release it slowly at night. White paint would reflect the sunlight and stop it from being absorbed by the buildings.

“In our study, we have detected an average reduction in temperature of 0.8 degrees during heatwaves, and peaks of up to four degrees lower at certain locations and during certain hours of the day,” Sergi Ventura, a meteorologist from UAB, told Euronews.

“We are collaborating with public entities such as [Barcelona’s] Urban Master Plan. They are in favour of painting roofs white. But so far nothing is being done. This is a low-cost strategy. And According to our predictions, in a city like Barcelona it would work even better than increasing green spaces,” he said.

With heatwaves becoming increasingly frequent and severe due to climate change, cities around the world are finding ways to combat the heat island effect.

The Barcelona city council also announced it will build 21 “green hubs” in the Eixample neighbourhood by 2030, as part of its  “Superbock” plans.

In 2020, Barcelona had its hottest year for more than 200 years with an average temperature of 16.8C.

Spain also marked its hottest year on record in 2020, with an average temperatures hitting 14.8 degrees celsius – around 1.7 degrees hotter than the average in pre-industrial times.

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Spain opposes EU green label for gas and nuclear energy

Spain and Denmark reiterated Monday their opposition to plans by the European Union to label gas and nuclear energy projects as green investments, an issue that has divided the bloc.

Spain opposes EU green label for gas and nuclear energy

The two nations believe such a move would send “the wrong message to
investors and society as a whole”, Spanish Prime Minister Pedro Sánchez told a joint news conference in Madrid with his Danish counterpart Mette Frederiksen.

The European Commission drafted plans late last year to label gas and
nuclear energy as green investments, a move it hopes will steer huge sums of private capital into activities that support EU climate goals.

READ ALSO: ‘Spain needs to change its ways’: Scientists warn over worsening drought

But Austria and Luxembourg have along with Spain and Denmark opposed the EU’s draft plans for a so-called “sustainable finance taxonomy”.

Heavyweight Germany opposes labelling nuclear power as sustainable, but not gas.

Sánchez and Frederiksen believe decisions about the new rulebook should
have a “strictly scientific basis”, a “position shared by Austria and Luxembourg”, the Spanish government said in a statement after the two leaders met.

EU member states are awaiting the commission’s final proposal, which it has
said it will publish soon, without giving a date.

Once published, a majority of the European Parliament or a super-majority
of EU member states – 20 of the 27 countries – could block the rules.

It is unlikely that such a majority will be reached since a dozen nations
including nuclear-reliant France back the new rulebook.