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Could white paint help Barcelona cope with frequent heatwaves?

Spain is warming at a faster rate than any other European country. In an effort to protect city-dwellers from worsening heatwaves, the Spanish government is considering painting Barcelona’s iconic buildings white.

Barcelona’s cityscape has long been hailed by urban planners and architectural novices for its practical design and abundant natural features.

But climate scientists are warning that current efforts to expand local green spaces won’t be enough to keep the capital cool as temperatures continue to skyrocket across the country.

Spain has recently been identified as the fastest warming country in the northern hemisphere, and although Barcelona is well-designed and dotted with greenery, it is one of Europe’s most densely populated areas. Its narrow streets and tightly packed homes are known to hold in heat on hot summer days.

This is a growing problem as the world continues to warm. Barcelona has been struck with record-breaking heatwaves in recent years, with annual temperature levels increasing between 1.7 and 1.9 degrees Celsius in urban areas.

As a result, scientists from the Autonomous University of Barcelona have proposed a climate adaptation project that involves painting the city’s rooftops white. They say it could reduce atmospheric temperatures by up to 4.7 degrees during heatwaves.

Does white paint actually work?

As far back as the 1970s, scientists and paint manufacturers began working together to develop bright white paint that reflects 80-90 percent of the sun’s rays. The goal at the time was to keep the surrounding environment and interior of buildings cooler.

In 2021, with the climate crisis at the forefront of society’s mind, a professor from Purdue University pushed the innovation even further by developing ultra-white paint that is capable of reflecting up to 98 percent of sunlight. He hopes to make it available on a wide scale in the near future in order to reduce overall global warming.

Today, many cities around the world including Sydney, Paris, New York, and Los Angeles, have seen local councils painting roads and rooftops with bright and reflective white paint to prevent reliance on cooling systems like air conditioning to cope with intensifying heatwaves.

Considering global average temperature records were broken multiple times last week – and with those records likely to be broken again this summer – adopting the white-paint project could be a simple and effective solution for many global cities feeling the heat.

Coating streets with white paint lowers temperatures

How has Barcelona approached climate adaptation so far?

In 2015, Barcelona announced a multi-faceted approach to addressing its biggest challenges posed by climate change.

To create the plan, it partnered with over 800 organisations including schools, businesses, NGOs. What resulted were nine citizen-led projects aimed at reducing CO2 emissions and increasing green spaces across the city.

The plan saw the government agree to subsidize 75 percent of rooftop garden projects, while creating urban allotments, and making space for renewable energy generation.

It has also committed to reducing overall emissions by 45 percent compared to 2005, improving access to cycle paths in the city, and reducing motor vehicle use by 20 percent by 2030.

In comparison with these major systemic changes, the white paint project has been described as a ‘patch solution.’ Setting the plan into action won’t drastically reduce overall emissions, help reduce water use, or boost its green energy sector.

However, it will serve to make the city more liveable for residents as these issues are addressed on a wider scale and reduce emissions produced by air conditioning systems – even if that means losing the charming, iconic scene provided by looking at Barcelona’s terracotta rooftops from above.