Over the next 40 years the construction sector will grow without limit, driving up energy demand. To meet the Paris Agreement, energy efficiency will need to be the watchword of new buildings.
Over the last decade, more than 50 billion square metres of new concrete floor space have been built on Earth — equivalent to an Empire State Building every 25 minutes, and in a single year as many buildings as the whole of Japan contains — a trend showing no sign of slowing, given that forecasts for the next 40 years estimate 230 billion square metres of new construction, equal to a new Paris every week. An alarming figure, when one considers that this development, on top of land consumption, brings with it a rise in energy consumption.
This is the finding of a report by the Global Alliance for Buildings and Construction (GABC), drawn up by the International Energy Agency on behalf of Unep, the United Nations environment programme. According to the study, the construction boom requires cuts in energy consumption if the climate objectives of the Paris Agreement are to be met.
The building sector, according to the dossier, accounts for 36 per cent of final energy consumption globally, and 82 per cent of its energy needs are met by fossil fuels. Buildings and construction are responsible for 39 per cent of CO2 emissions.
To achieve the Paris objectives and keep the rise in global warming within 2°C, the energy efficiency of buildings must improve by 30 per cent relative to 2015 levels by 2030, to the point where, over the next decade, zero-emission and nearly zero-energy buildings should become the global standard.
The dossier highlights the rapid growth of construction on a global scale: at this rate, by 2060 the total floor space of buildings worldwide will double. 230 billion square metres will be built (encompassing the floor area of every storey of every new building), to be added to the approximately 235 billion square metres existing in 2016.
Rapid growth that is not without negative effects. Although the energy intensity of the sector has improved in recent years, it is nonetheless insufficient to reduce the rise in energy demand. CO2 emissions have continued to grow by one per cent a year since 2010, and over four million deaths a year are attributable to diseases caused by pollution produced by buildings.
The construction sector has seen very few changes in terms of improvements in energy efficiency. According to John Dulac, energy analyst at the IEA, "the sector accounts for approximately 30 per cent of final energy use worldwide and its energy-saving potential is enormous, but for now it represents a major missed opportunity."
Little has been done in past decades to improve the energy efficiency levels of buildings, but if more were invested in the sector "the untapped potential would translate into enormous energy savings," writes Dulac. If high energy-performance buildings were constructed and existing ones retrofitted, it would be possible to save approximately 91,000 TWh (330 exajoules) up to 2060, more than all the final energy consumption of the G20 countries in 2015. Using high-efficiency heating and cooling technologies would cut consumption by a further 180 TWh (660 exajoules) in terms of global energy demand, equivalent to China's final energy consumption over the last ten years.
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There are several obstacles on the path to energy efficiency in buildings, foremost among them the lack of standards and a common language. "A unified language is absolutely necessary if the construction sector is to grow and rise to the climate challenge. Other sectors have developed and use common languages, such as ICT communication protocols, and this is their strength. The construction industry is unable to respond to the 'performance gap' because it is not able to define precisely the physical quantities to be compared," explained Lorenzo Pagliano, professor in the Department of Energy at the Politecnico di Milan, who collaborated on the Global Alliance for Buildings and Construction report. Almost 70 per cent of construction energy consumption worldwide is not covered by mandatory codes and standards, and today two thirds of countries have no energy regulations for the construction of new buildings. This means that over the next 40 years, a new 100 billion cubic metres of buildings (out of the 235 billion forecast) will have no mandatory energy code to comply with.