Video (2018) with aerial shots of the Panarbora site in Waldbröhl.

To live up to its climate change pledge under the Paris Agreement, the European Union must ensure that all 250 million existing buildings, as well as all new buildings in the EU, produce near-zero greenhouse gas emissions. In a new report, European national academies of science, through their association EASAC, call for far-reaching policy action. "Policies have long focused on creating energy-efficient buildings that require less heating and air conditioning or generate renewable energy on site. However, the energy used to operate buildings is only part of the story. We need to broaden the scope and look at emissions from building materials and methods - both for new buildings and for building refurbishment," says William Gillett, Director of EASAC's Energy Programme.

Currently, between 1 and 1.5 % of Europe's building stock is retrofitted each year. "To meet the Paris Agreement targets, this rate should be two or even three times higher," Gillett points out. "But more importantly, when calculating the climate impact of buildings, we need to include the massive emissions from the construction industry and supply chain. Renovating a building to reduce energy consumption makes little sense if there is no regulation of CO2-content of the building materials and components used in the remediation and when they are transported long distances."

Until now, EU policy has focused on the concept of 'near-zero energy buildings', with an emphasis on reducing the energy consumption needed for the comfort of building occupants. According to the European Academies of Science, this notion is outdated: "As an indicator for assessing the climate impact of a new building or renovation, greenhouse gas emissions over the whole life cycle should now be considered, i.e. both the emissions generated by the production of the building materials and construction works and the emissions generated by the use of the building in the years afterwards. In just under 10 years, the door closes on limiting global warming to less than 1.5°C. During this period, there is an urgent need to limit the creation of greenhouse gas emissions in the upstream chain of renovation to create near-zero emission buildings."

Buildings should be designed so that they can be dismantled and recycled at the end of their life.

The report points out that most of the built environment is still designed according to a linear take-make-consume-dispose approach. The transition to a circular economy would not only make it possible to reduce resource consumption and CO2-footprint, but also to address the problem of waste. "Circular economy has many facets," explains Prof. Brian Norton, co-chair of the EASAC working group that produced the report. "Many building materials can be reused, recycled and recovered. First of all, buildings and their components should be designed to be easily dismantled at the end of their use."

Energy retrofitting of existing buildings must be at the heart of the EU's strategy, the researchers argue. "It is important to consider the re-use of existing buildings rather than replacing existing buildings with new ones," says Prof Norton. "There is a lot of CO in a building envelope.2, especially in concrete and steel. With today's technologies and digitized processes, renovation has become much easier and more sustainable. We need to stop the current practice of tearing down structures to build them from scratch." The report also argues that legislation should set a limit on CO2-The Commission is of the opinion that it is necessary to establish a limit value per m² of floor area that may be introduced into a building when it is being constructed or renovated.

Climate neutrality by 2050 requires the refurbishment of more than 90,000 homes - per week!

Last year, the European Commission presented its "Renovation Wave" strategy to drive forward the energy renovation of buildings in the EU. It intends to revise the Energy Performance of Buildings Directive as one of the cornerstones of this strategy. "It is true that an Energy Performance of Buildings Directive has been in place since 2002, recast in 2010 and revised in 2018. But the results have been underwhelming," says Dr Gillett.

The challenge is huge. "An estimated 75 % of the buildings Europeans live in have poor energy performance. To retrofit them would require 146 million renovations in just 30 years. Current efforts by member states are not enough," explains Prof Norton. "To achieve climate neutrality, we would need to renovate more than 90,000 homes a week across the EU - a huge challenge in itself."

Buildings are a source of emissions over which local authorities have a major influence

While the European Academies of Science direct their policy recommendations primarily to the European Union, they also make clear that cities play a major role. "Local councils and city planners have a huge influence on procurement specifications. They can stimulate the renovation and construction of neighbourhoods with near-zero greenhouse gas emissions, integrated energy and transport systems, and adequate green spaces. They can facilitate upgrades to existing district heating and cooling systems, or build new systems with optimized use of renewable energy, including photovoltaics, heat pumps, solar, geothermal, waste heat, and natural cooling. And they are particularly well placed to drive the renovation of social housing and subsidise the basic refurbishment of private homes where this is needed to reduce fuel poverty," says Prof Norton.

EASAC's messages to policy makers

Phasing out fossil fuels by 2030, increasing the integrated supply of CO2-free electricity and heat to buildings, industry and transport, and accelerating the use of carbon capture and storage.

1. Provide grants and incentives to trigger, boost and reduce the risk of private financing for energy-efficient building retrofits.
2. Regulating the level of greenhouse gas emissions in building materials and components and promoting material recycling, reuse of building components and renovation instead of demolition.
3. Realign building codes, certification systems, and incentives for new and renovated buildings with near-zero greenhouse gas emissions.
4. Promote health and wellness to double/triple renovation rates that improve air quality, increase access to daylight, prevent drafts and overheating, and reduce GHG emissions.
5. Engaging public authorities and cities, supporting commitments to decarbonise buildings and reduce fuel poverty.
6. Expand and modernize the construction industry to work with circular models, with 3 million additional jobs (including highly skilled jobs) to deliver new and renovated buildings with near-zero GHG emissions.
7. Improve access for builders and professionals to certified data on the GHG emissions content of building materials and components, and on the energy and GHG emissions performance of new and renovated buildings.
8. Update EU legislation (Buildings Directive, Renewable Energy Directive, Efficiency Directive, Emissions Trading, Taxonomy) using an integrated approach to phase out fossil fuels, increase renewable energy supply and reduce cumulative GHG emissions from buildings.

About the European Academies' Scientific Advisory Committee (EASAC)
The national science academies of the countries of the European Union joined forces in 2001 in the European Academies' Science Advisory Council (EASAC). EASAC, as an advisory committee of the European science academies, prepares statements, reports and popular science writings on current socially relevant topics in the fields of energy, environment and life sciences and addresses these to the institutions of the EU.
http://easac.eu

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