Current and Future Climate in Lisbon and Porto

As we’ve mentioned in our first article, our services are adapted to the changing climate. Building regulations and techniques are still based on observed climate data, but at Dosta Tec we aim at being frontrunners looking into the future. Lisbon and Porto are the two centres of the largest metropolitan areas in Portugal, concentrating almost half of the population of the country. Most of the building stock in these areas dates from before the 1990s (when thermal insulation for walls and double glazed windows were introduced) [1] and is not prepared for the current and future climate. Additionally, it does not reply to current thermal comfort standards or energy efficiency requirements.

The average observed (1971–2000) temperature in January in Porto was 7.6°C, but according to the RCP 8.5 scenario [more here] would be 1.7 °C higher in 30–50 years. This means much warmer and milder winters. In August the average observed temperature oscillates around 21.1 °C, while in 30–50 years it would rise to 23.9°C. At the same time, the amount of extreme heat days is likely to grow. Lisbon in January saw an average temperature as low as 9.3°C, but in 30–50 years, it would rise to 11.2°C. In August the average observed temperature was 23.3°C and would rise to 25.4°C. Also, the average maximum temperature would stay above 30°C during the summer months, posing a big challenge regarding the cooling of buildings

Mean temperature in January in Porto and Lisbon

The northern regions would receive more rain in the winter period, though accumulated in a shorter period of time, while the south would receive even less rain in the summer which may cause additional feedback loops in the local temperature growth. The sky overcast, humidity, and consequently the global radiation hardly change, which guarantee the continued use of solar energy. Portugal has the opportunity to grow vastly in this area and catch up with its European neighbours. The number of windy days grows (by about 10 days a year) which suggests reviewing the use of wind energy.

Generally, almost the entire territory of continental Portugal would enjoy a dry-summer subtropical climate, today native to the southern part of the country, with hotter summers and milder winter, though with more often temperature extreme events.

Fortunately, both cities enjoy the proximity to the ocean and large inland water bodies which regulates the temperature amplitude. For further inland locations, also within the metropolitan area, temperatures tend to vary more, with higher extremes. We should also consider the effect of rising sea levels.

The question that arises here is how to design for future energy efficiency — how much insulation does a new construction need and how to renovate the existing building stock for a warmer climate. How to benefit from renewable energies to design energy-positive buildings? We, at Dosta Tec, are developing strategies that consider these changes to create buildings that change with climate. By means of computational tools, we simulate building behaviour in the future climate.

Adrian Krężlik

Co-founder of Dosta Tec

[1] Edifícios segundo os Censos: total e por época de construção, INE, PORDATA, 2013

The climate data are based on information by Instituto Português do Mar e da Atmosfera in the frame of project Adaptation to Climate Change and Portal do Clima,