The Earth has had a negative resource balance for years, as the calculations for "Earth Overshoot Day" make clear. The construction and property industry plays a key role in moving this day further back in the calendar year. To achieve this, it is essential to consider grey energy during construction in addition to operating emissions.
We are living on an ecopump. This is shown by the analyses of the Global Footprint Network's Earth Overshoot Day. The day marks the point in the year when human demand for resources exceeds the earth's regenerative capacity. The calculations have been published annually since 1961 and paint a bleak picture. Last year, the date on which the entire human race used up the limit of planetary resources fell on 2 August.
The DACH region cuts a very poor figure. If everyone lived like Switzerland, the planetary budget would have been exhausted after 132 days, i.e. on 13 May 2023, according to the last calculation. Germany and Austria fare even worse, with only 123 days and 95 days respectively within the naturally available resource budget.
The property sector as a key player
Now for the good news: with its resource consumption, energy use and site development projects, the construction and property industry can make a significant contribution to reducing the global ecological footprint and thus delay Earth Overshoot Day.
But first things first. Under the motto Power of Opportunity and accompanied by the hashtag #Move - TheDate, the Global Footprint Network has identified five key areas that are particularly promising in the efforts to achieve greater resource security: planet, cities, energy, food and population. As a cross-sector industry, the construction and real estate sector ties in with several of these areas, particularly with the development of smart cities and efforts to decarbonise the building stock.
Earth Overshoot Day is just one of several initiatives calling for a shift towards a circular economy. With the European Union's Green Deal and the political commitment to climate neutrality, specific laws and regulations are now also being drafted or at least discussed that call for a rethink in the construction and property industry.
Grey energy as a relevant aspect
This is no coincidence. After all, the property sector in this country is considered one of the main emitters of CO2 emissions and the cause of immense mountains of waste. This provides considerable leverage to help reduce the negative environmental impact by introducing sustainable principles and measures.
But reduction alone is not enough. The path to climate neutrality also requires a new way of thinking and working that scrutinises and changes existing construction processes from the ground up. Against the backdrop of the prevailing scarcity of resources and material shortages on European construction sites, the circular economy is becoming even more important.
Sustainability efforts in the property industry still often focus on operating emissions. However, in order to achieve the goals of climate neutrality by 2050 - and thus effectively support the postponement of Earth Overshoot Day - we must quickly turn our attention to construction emissions. This so-called grey energy refers to the total energy required to construct a building. This includes the extraction of raw materials, the production and processing of components, the transport of materials and components to the construction site, their installation in the building and ultimately the dismantling and disposal of the building materials.
A reduction in grey energy through more sustainable construction practices, climate-friendly material selection and the efficient, long-term use of raw materials contributes directly to reducing the ecological footprint and thus to improving the overall resource balance.
Limit values for grey emissions in the EU
Some countries have already introduced laws and regulations aimed at limiting grey energy in the real estate sector and promoting sustainable building practices. Denmark, for example, which currently ranks an inglorious eighth among overshoot countries with only 86 days within planetary boundaries, is actively pursuing the decarbonisation of its building stock with its Strategy for Sustainable Construction.
Since the beginning of 2023, a legal limit of 12 kgCO2eq/m2/a has been in force for buildings larger than 1000 square metres, which must be verified by a life cycle assessment over the entire life cycle. Denmark is the first EU member state with such requirements and plans to tighten them further in two years' time and extend them to all buildings, including those smaller than 1000 square metres. The reduction path for construction emissions is set every two years through reduced limit values, although the values for the coming years have not yet been defined.
Various EU member states such as Finland (89 days), Sweden (92 days), the Netherlands (101 days) and France (130 days) have also introduced life cycle assessment regulations and are preparing to introduce threshold values for their preparation in the near future. It can therefore be assumed that the majority of nations in Western Europe will follow Denmark's example in the foreseeable future. This means that limit values for grey greenhouse gas emissions will effectively become standard for the planning and construction of properties in our latitudes.
In Switzerland, there are currently no legal requirements for grey energy (yet). The SIA Fact Sheets 2032 Grey Energy - Life Cycle Assessment for the Construction of Buildings and 2040 Energy Efficiency Path form the essential basis for planning and construction.
Real estate as a raw material store
One reason for the neglected treatment of construction emissions to date is the incomplete data situation and the complex quantifiability. This is because the many different players, regions, transport routes and supply chains in the construction process often lead to incomplete data sets and make it difficult to monitor grey energy efficiently. The first step is therefore to have clear calculation models and, above all, real, up-to-date data. In order to achieve economies of scale, this data must be recorded precisely, materials must be carefully documented during installation and the development and standardisation of circular processes, standards and tools must be actively promoted. Only if the raw materials once used are reused on the next construction site or in the next property at the end of the building life cycle instead of ending up in a landfill will properties become efficient raw material stores (and also a lucrative investment).