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Indicator Specification
Space heating and cooling is responsible for a large fraction of European energy use. Heating degree days (HDDs) and cooling degree days (CDDs) are proxies for the energy demand needed to heat or cool, respectively, a home or a business. Both variables are derived from measurements of outside air temperature. The heating and cooling requirements for a given structure at a specific location are considered, to some degree, proportional to the number of HDDs and CDDs at that location. However, they also depend on various other factors, such as building design and insulation, availability and type of heating and cooling systems, energy prices and income levels, and behavioural aspects.
A decrease in the demand for space heating can significantly decrease overall energy use in Europe, but this gain can be offset in part or completely by an increase in cooling demand. Furthermore, heating is delivered to end users in different ways (individual boilers fuelled by oil, gas and coal, and electricity and district heating), whereas cooling is delivered currently almost exclusively through electricity. As a result, a given change in cooling demand is generally associated with larger costs, a larger change in primary energy demand and larger impacts on the peak capacity of supply networks than the same change in heating demand.
In April 2013, the European Commission (EC) presented the EU Adaptation Strategy Package. This package consists of the EU Strategy on adaptation to climate change (COM/2013/216 final) and a number of supporting documents. The overall aim of the EU Adaptation Strategy is to contribute to a more climate-resilient Europe.
One of the objectives of the EU Adaptation Strategy is 'Better informed decision-making'. This shall be achieved by bridging the knowledge gap and further developing the European climate adaptation platform (Climate-ADAPT) as the ‘first-stop shop’ for adaptation information in Europe. Climate-ADAPT has been developed jointly by the EC and the EEA to share knowledge on (1) observed and projected climate change and its impacts on environmental and social systems and on human health; (2) relevant research; (3) EU, transnational, national and sub-national adaptation strategies and plans; and (4) adaptation case studies. It was relaunched in early 2019 with a new design and updated content. Further objectives include 'Promoting adaptation in key vulnerable sectors through climate-proofing EU sector policies' and 'Promoting action by Member States'.
Most EU Member States have already adopted national adaptation strategies and many have also prepared action plans on climate change adaptation. The EC also supports adaptation in cities through the Covenant of Mayors for Climate and Energy initiative.
In November 2018, the Commission published its evaluation of the 2013 EU Adaptation Strategy. The evaluation package includes a Report from the Commission, a Commission Staff Working Document, the Adaptation preparedness scoreboard country fiches, and the reports from the JRC PESETA III project. This evaluation includes recommendations for the further development and implementation of adaptation policies at all levels.
In November 2013, the European Parliament and the European Council adopted the 7th EU Environment Action Programme (7th EAP) to 2020, ‘Living well, within the limits of our planet’. The 7th EAP is intended to help guide EU action on environment and climate change up to and beyond 2020. It highlights that ‘Action to mitigate and adapt to climate change will increase the resilience of the Union’s economy and society, while stimulating innovation and protecting the Union’s natural resources.’ Consequently, several priority objectives of the 7th EAP refer to climate change adaptation.
In February 2016, the Commission published an EU Strategy on Heating and Cooling, which aims to decarbonise the heating and cooling of buildings through different technologies and measures, in line with wider EU climate and energy policies.
No targets have been specified.
HDDs and CDDs are defined relative to a base temperature — the outside temperature — below which a building is assumed to need heating or cooling. They can be computed in different ways, depending, among other things, on the specific target application and the availability of sub-daily temperature data. Previous versions of this indicator published before 2016 applied the methodology of Eurostat, which uses daily mean temperature only and has a jump discontinuity when daily mean temperature falls below the base temperature. This indicator uses an approach developed by the UK Met Office, which uses daily mean, minimum and maximum temperatures and does not exhibit a discontinuity. Note that this approach, being based on both minimum (Tn) and maximum (Tx) temperatures and not solely on the mean temperature (Tm), increases the accuracy of HDDs and CDDs for the purpose of gauging the impacts of climate change on energy demand, because the cooling of the environment depends more on Tx than on Tm, while Tn is more relevant for heating. The baseline temperatures for HDDs and CDDs are 15.5 °C and 22 °C, respectively. As a result of the methodological changes, the magnitudes of the trends between this version of the indicator and versions published before 2016 cannot be directly compared.
The aggregation of regional changes in HDDs and CDDs to larger areas can be done using area weighting or population weighting (with a fixed population). Population weighting is preferable for estimating trends in energy demand over large regions with an uneven population distribution, such as Europe.
Not applicable
Not applicable
The climatological input data sets for computing past trends for HDDs and CDDs in Europe combine temperature data with daily resolution from three different station data sets — the JRC’s MARS meteorological database, the NOAA National Climatic Data Center (NCDC)’s Global Historical Climatology Network data set and the European Climate and Assessment Dataset of the Royal Meteorological Institute of the Netherlands — and from one gridded data set (E-OBS versions 17). The resulting trends are considered robust in most regions, but there are open questions for some regions with poor station coverage.
HDD and CDD projections are derived from the ensemble mean of 11 high‐resolution bias‐adjusted EURO‐CORDEX simulations. Climate simulations are associated with uncertainties related to the underlying emissions or forcing scenario, natural variability and model uncertainty. However, temperature is generally simulated better than other climate variables, and the use of multi-model averages and of bias adjustment further reduces errors in individual simulations.
Different definitions exist for computing HDDs and CDDs, which can lead to different magnitudes of calculated trends.
No uncertainty has been specified
Work specified here requires to be completed within 1 year from now.
Work specified here will require more than 1 year (from now) to be completed.
For references, please go to https://www.eea.europa.eu/data-and-maps/indicators/heating-degree-days-2 or scan the QR code.
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