What exactly is a heatwave?

A heatwave is a prolonged period of much-warmer-than-average weather. A heatwave would typically last for several days to a few weeks, involve temperatures that are much higher than usual for the region in question, and in some regions may be accompanied by high humidity levels, which can exacerbate the effects of the heat on the human body. Heatwaves can carry various risks, depending on the region where they are experienced. For example, economic risks, including from agricultural losses, wildfires and power shortages. When they reach more extreme temperatures, heatwaves also bring significant health risks such as heat exhaustion and heatstroke, especially for vulnerable populations like the elderly and young children (see ‘Heatwave impacts’ below).

Defining a heatwave

There is no internationally agreed definition of a heatwave, but the term is always used in exceptional circumstances. Different regions and countries use varying thresholds for heatwaves based on local impact, which consider variations in climate, geography, and societal contexts. Definitions may also depend on how the temperature data are being used. For example, in the European State of the Climate 2023, the definition used was ‘a period of at least three consecutive days when both the daily surface air temperature minima and maxima are higher than the highest 5% of values for the day in question during the 1991–2020 reference period’. Animation from the European State of the Climate 2023 showing the development of heatwaves across Europe from June to September 2023. Credit C3S, ECMWF.

Heatwave impacts

For most parts of the world, heatwaves are associated with high temperatures. According to the World Health Organization (WHO), heat stress is the leading cause of weather-related deaths and can exacerbate underlying illnesses including cardiovascular disease, diabetes, mental health and asthma, and can increase the risk of accidents and transmission of some infectious diseases. The human body can struggle to regulate its temperature when faced with prolonged exposure to high temperatures, resulting in heat stress. Healthcare systems also come under increased pressure from the increased incidence of heat-related illnesses. You can find out more about heat stress and its impacts in this article. Extreme heat has been by far the leading cause of reported deaths due to extreme weather and climate events in Europe in recent decades. Between 55,000 and 72,000 deaths were estimated in each summer of 2003, 2010 and 2022 due to heatwaves. Between 2000 and 2020, heat-related deaths are estimated to have increased in 94% of the European regions monitored.[1] Heatwaves can have significant environmental and socio-economic impacts, particularly when combined with prolonged periods of dry weather and drought. In these situations, periods of extreme heat can reduce soil moisture, decrease river flows, and deplete groundwater reserves. This in turn can affect water availability for agricultural, industrial and domestic use. The reduction in water supply can lead to conflicts over water resources, increased costs for water extraction and distribution, and challenges in maintaining water quality as lower water levels concentrate pollutants. In agriculture, heatwaves can severely damage crops and reduce yields. Higher-than-average temperatures can stress plants, impair their growth, and lead to heat-related diseases. Livestock are also affected, with increased risk of heat stress and reduced productivity. Additionally, marine heatwaves can impact fisheries and aquaculture by increasing water temperatures, which can affect fish health and reduce yields. This results in economic losses for producers and higher food prices for consumers. Other economic impacts arise from spikes in energy demand, as people use more air conditioning, leading to higher electricity costs and the risk of power outages. Tourism in warmer climates can also suffer, as extreme heat may deter visitors, leading to lost revenue for tourism-dependent economies. Heatwaves can also disrupt transport systems, as high temperatures can warp rail tracks, damage road surfaces, cause river transport routes to narrow and dry up, and affect the performance of aircraft engines. Confluence of the Nahe and Rhine rivers at Bingen, Germany. Rocks and sandbars are visible due to an unusually low water level after extended drought in 2022. Water supply and quality are compromised during heatwaves. Increased temperatures can lead to higher evaporation rates, reducing the availability of surface water sources such as lakes and reservoirs. This can put additional strain on water supplies, particularly in areas already experiencing drought. Furthermore, higher temperatures can promote the growth of harmful algal blooms in water bodies, which can contaminate drinking water supplies and pose health risks to both humans and wildlife.

Marine heatwaves

Marine heatwaves are defined as prolonged periods of anomalously warm sea surface temperature (SST) that can be characterised by, for example, their duration, intensity and spatial extent. Due to their potential impact on marine ecosystems and the associated marine economy, marine heatwaves have received wide coverage over the past few years.[2] In the European State of the Climate 2023 report, it was shown that in 2023 both the global ocean heat and the average SST across Europe were the highest ever recorded. In June 2023, the Atlantic Ocean west of Ireland and around the United Kingdom was impacted by a marine heatwave that brought SSTs as much as 5°C above average. In July and August 2023, marine heatwaves in the Mediterranean Sea saw even higher SSTs, reaching 5.5°C above average in some areas. Marine heatwaves are often driven by oceanic and atmospheric conditions such as El Niño events, changes in ocean currents, and atmospheric blocking patterns that reduce mixing of surface water with cooler, deeper water. Increased absorption of solar radiation and reduced wind-driven evaporation can also contribute. Marine heatwaves have profound impacts on marine ecosystems, leading to widespread coral bleaching, where prolonged elevated temperatures cause corals to expel the algae they rely on for energy, often resulting in coral death. These heatwaves can also cause shifts in species distributions as marine organisms move to cooler waters which, in turn, can lead to significant disruptions in marine food systems, affecting the abundance and diversity of marine life. Consequently, fisheries and local economies that depend on marine resources suffer, with reduced fish stocks and changes in species composition leading to economic losses and food security issues for coastal communities. As with land heatwaves, different countries and international organisations may have varying criteria and scales for defining and classifying marine heatwaves. The National Oceanic and Atmospheric Administration Marine Heatwave Categories are commonly used. These range from Category 1 (Moderate) to Category 5 (Beyond Extreme), based on the intensity and duration of SST anomalies relative to the long-term average.

Marine heatwaves and hurricanes

Hurricanes, also called tropical cyclones or typhoons, depending on where they form, derive their energy from warm SSTs of at least 27°C. The warmer-than-average SSTs that result from marine heatwaves can thus intensify the wind speeds of hurricanes, giving them the potential to deliver more damage if they make landfall. Marine heatwaves can also prolong the period during which SSTs are warm enough to support hurricane activity. This can extend the hurricane season, leading to a higher probability of hurricane formation outside the typical season. With climate change expected to increase the intensity of marine heatwaves, it is possible that this will influence hurricane activity, but there is a lot of uncertainty, especially at a regional level.

What causes a heatwave?

Heatwaves are primarily caused by high-pressure systems that trap warm air in a particular area, preventing it from dissipating. These high-pressure systems, also known as anticyclones, create a dome of heat by forcing air to sink and compress, which increases temperatures at the surface. The lack of cloud cover under these high-pressure systems allows for greater solar radiation, further heating the ground and the air above it. This combination of factors can result in prolonged periods of excessively high temperatures, often lasting several days to weeks. How a heat dome forms, adapted from AFP, 2021 and Hills and others, 2021. Source: Eberle, Caitlyn & Higuera Roa, Oscar & Sparkes, Edward. (2022). Technical Report: British Columbia heatwave. Climate change is also a significant factor contributing to the increasing frequency and intensity of heatwaves. The rise in global temperatures due to the accumulation of greenhouse gases in the atmosphere enhances the likelihood of extreme heat events. Warmer baseline temperatures mean that heatwaves start from a higher point, making them more severe. Additionally, climate change can alter atmospheric circulation patterns, potentially leading to more persistent high-pressure systems that are conducive to heatwaves. Other contributing factors include urbanisation and land-use changes. Urban areas, with their dense infrastructure and limited green spaces, experience the urban heat island effect, where temperatures are higher than in surrounding rural areas. This effect can amplify the intensity and duration of heatwaves in cities. Land-use changes, such as deforestation and agriculture, can also influence local climates by altering the surface energy balance, affecting local temperature and humidity levels.

A bit of context

The frequency and intensity of extreme heat events is increasing in Europe. According to the WMO Europe Regional Climate Centre (RCC), 23 of the 30 most severe heatwaves in Europe since 1950 have occurred since 2000, and five in the last three years.[1] The 30 most severe heatwaves in Europe, 1950–2023. The size of a circle is proportional to the area affected by the corresponding heatwave. Heatwaves ranked as more severe are indicated by darker colours, and grey indicates those with a ranking of severity below 10. Source: DWD. Credit: DWD/C3S/ECMWF. Heatwaves and their impacts are covered in detail in the European State of the Climate 2023 report, in sections on ‘Extreme weather and human health’ and ‘Temperature and thermal stress’.

Heatwave mitigation and adaptation

A herd of Charolais cows drink from a trough filled twice a day by a farmer using a water tanker, as his meadows are not connected to a water network, in Bennetot, western France, on July 18, 2022.

Heatwaves in Europe in the past week have seen exceptionally hot weather wreaking havoc across the continent. In France, Greece, Spain and Portugal, temperatures above 40C sparked wildfires that forced tens of thousands to evacuate from their homes. In the UK, a record high of 40.3C brought on travel chaos and fears of a health emergency.

>> ‘We’ve lost everything’: Tourists evacuated in France’s Gironde as wildfires rage

Even when the heat has not caused obvious damage, the impact of such extreme weather can have lasting effect, especially on food production. The result is likely to be “heatflation”, unusually hot temperatures causing smaller harvests and rising food prices.

In Italy, for example, the mid-July heatwave was one in a series that has hit the country this summer. As a consequence, agriculture union Coldiretti has warned that drought is threatening 30-40 percent of the national seasonal harvest.

Throughout Europe, July’s heatwave hit at during a crucial pollination window for maize crops, threatening to reduce overall harvests and increase import needs. At the same time, experts forecast a decline in milk production that could last for weeks due to overheated livestock.

“Demand globally is exceeding supply”

The impact of heatflation could be felt over the coming months. For grain crops such as wheat, rice and maize, prices on commodity markets are set in advance, based on forecasts of how successful a harvest will be. “Any expectation that there’s going to be a shortage, however small or big, normally manifests itself in four to six months,” says Dominic Moran, a professor of agricultural and resource economics at the University of Edinburgh.

As harvest season has already started for much produce, the July heatwave did not damage as many crops as it could have. But in the current economic context, impact of heatflation could still hit hard.

“We are in a food, energy and cost-of-living crisis, created by COVID-19, exacerbated by Russia’s invasion of Ukraine,” says Professor Tim Benton, Director of the Environment and Society Programme at international affairs think tank Chatham House. “In a disrupted market – where demand globally is exceeding supply – any loss of harvest does not help prices.”

In May 2022, financial services provider Allianz found that food and drink prices in Eurozone countries had increased by an average of 14% since the start of 2021. At the same time, retail prices had only risen by 6%, meaning retailers had yet to pass the worst of the price hikes from food producers on to consumers.

By the time these hikes are fully reflected in supermarket prices, Allianz forecast that the average European consumer will be spending an extra €243 for a basket of food products compared with 2021, before heatflation is factored in.

Aside from maize, the products most likely to be impacted by the July heatwave include root crops such as potatoes and sugar beets. “They take a lot of water and they don’t tolerate heat-stress or drought conditions at the wrong time of year,” Moran says.

The cost of livestock farming also rises exponentially in the heat. Moran adds, “cattle don’t like heat so you’ve got to put them indoors to control their temperature. Then you’re forced to keep them cool with energy and, depending on where you live, energy prices are skyrocketing.” Heat-induced stress can also change how animals behave, causing chickens to lay fewer eggs and dairy cows to produce less milk.

“A drastic adaptation”

As hotter temperatures look set to become a regular occurrence in the future, how can food systems mitigate the impact on costs for consumers?

One option some farmers are turning to is switching crops to grow foods that are more resistant to extreme heat and drought. “Those decisions are being made right now in many countries,” Moran says. “We have an international network of crop breeding centres which are improving crops for that reason.”

But it will not be possible for everyone. In some areas, climate change is pushing temperatures so high that land will no longer be suitable for agricultural use. “That’s far more drastic … but it’s not impossible”, Moran says.

Another option is rethinking how global food systems work altogether. The current model is “super-efficient and just-in-time, where food is cheap above all,” says Benton. “Resilient food systems have more storage in-built, more diversity of supply routes, sources and produce, more decentralisation rather than big processing and distribution centres, and more agility.”

A resilient system is more expensive, which would not make for cheaper food costs. But it would ensure food provision was less vulnerable to climate shocks, benefitting consumers and even increasing political stability.

In June 2010 extreme heat in Russia and Ukraine reduced yields “to about the same amount the current war has,” Benton says. The resulting price hike for wheat flour had dramatic effects globally, increasing food insecurity, poverty and civil unrest in multiple countries. The Arab Spring was propelled forward by unrest caused by soaring bread prices.

“The era of cheap food is coming to an end”

In 2021, the UN’s Intergovernmental Panel on Climate Change concluded it was inevitable that there would be an “increasing occurrence” of record-breaking extreme weather. In a changing climate that is likely to become more volatile, heatflation is one result of a snowballing food production issue.

While heatwaves struck in Europe, climate events have impacted global production around the world this year.

In Southern China, heavy summer rains and floods disrupted rice, fruit and vegetable production. Drought impacted winter wheat yields in the US and corn and soy bean crops in Argentina. All this disruption in the first half of the year does not bode well for what is to come next.

“Looking ahead, our global food system is too fragile to absorb shocks – from climate or otherwise – and therefore we need to think about increasing its resilience,” Benton says. “Perhaps, therefore, the era of cheap food is coming to an end.”

Heating and cooling in the EU

The EU’s heating and cooling needs in 2020 accounted for half of its total gross final energy consumption (Eurostat, 2022b). This significant share has persisted for over a decade, despite many EU and national efforts to lower heating and cooling needs[1] to meet the EU’s headline 20% energy-saving target by 2020.

Heating buildings accounts for the largest share of energy used for heating and cooling in the EU, with space and water heating accounting for about 60%, while industrial heat demand accounts for about a third of heating and cooling needs. The remaining energy used for heating and cooling is consumed in agriculture and for cooling (EC, 2022c).

In 2020, residential and industrial heating and cooling demand was only 10% below the average annual level seen from 2005 to 2009, despite the COVID-19 pandemic having suppressed industrial activity and an exceptionally mild winter having lowered the heating needs in most of Europe’s buildings (EU, 2012; EEA, 2022b). This indicates sluggish progress in achieving a permanent reduction in heating and cooling needs.

What is heat? Heat is a valuable form of energy that supports meaningful end uses, such as the heating of residential and commercial buildings and for industrial processes. Across the EU, most energy is used to heat buildings and for industrial activities. Heat can also be used to generate electricity for various end uses, including heating. As heat is not a physical substance, it cannot easily be distinguished by origin, composition or intended use.

Buildings

With many EU countries having large stocks of old and energy-inefficient buildings, high-temperature heating systems are used to compensate for significant heat losses (EC, 2022c). Buildings consumed more than two fifths (42%) of all final energy used by all sectors in 2020, making them a main source of greenhouse gas emissions[2]. Households consumed two thirds of this energy, as illustrated in Figure 1 (Eurostat, 2022a). Historically, efficiency improvements have often coincided with higher levels of heat and electricity use in buildings, due to the increasing sizes and lower occupancy rates of dwellings, reduced energy prices, growing demand for cooling and prolonged use of more electrical equipment. In some cases, this increased use has outweighed the benefits of increased energy efficiency (SEAI, 2018; Central Statistics Office Ireland, 2022; EEA, 2022b; IPCC, 2022). Across the EU, however, the average energy consumption per household has slightly decreased since the peak of 2010, implying that energy efficiency efforts are starting to pay off (Eurostat, 2022a).

Figure 1. Final energy consumption by end-use sector, EU, 2020

Note: Mtoe, million tonnes of oil equivalent.

Source: ESTAT (2022).

Explore different chart formats and data here

While residential cooling needs currently account for less than 1% of the total EU energy used for heating and cooling in buildings, as average temperatures continue to rise across the EU, demand for cooling is likely to increase and that of winter-related heating to decrease. Between 2012 and 2021, the mean European land temperature was already almost 2°C warmer than the pre-industrial level (EEA, 2020).

Figure 2. Final energy uses across EU households, with space and water heating disaggregated by fuel type, 2020

Source: ESTAT (2022).

Explore different chart formats and data here

In 2020, space and water heating accounted for four fifths (78%) of all household energy use[3]. More than half of this energy for heating (57%) was supplied by direct domestic high-temperature heating systems burning fossil fuels — notably gas (39%), oil (15%) and coal (4%) (see Figure 2).

How is heat produced? Heat is typically obtained by oxidising the chemical energy in fuels[4], converting the energy in solar radiation, extracting ambient energy from the surroundings (air, water, soil and geothermal sources) or converting electricity in heaters. It can be produced centrally, in specialised energy plants and in other enterprises from where it is piped to consumers, or heat production can be decentralised, such as when citizens, businesses and the public sector use energy to heat buildings, to produce hot water and for cooking. Combined heat and power plants are typical examples of specialised energy industries that produce heat centrally and distribute it via pipes to end users. Other industries can also produce heat, including as a by-product, such as when heat released by exothermic chemical processes is recovered and sold to consumers. What are renewable heat sources? Solar thermal, geothermal and biomass fuels produced and used in a sustainable way[5] (including biogas injected into the grid and renewable municipal waste) are renewable heat sources. Ambient heat extracted from the environment by heat pumps is also a renewable heat source.

Fossil fuels also play a role upstream, when derived heat (typically hot water) and electricity are produced industrially in larger systems and supplied via grids for domestic heating. In district heating, which supplies about 10% of the EU’s heat and is more common in northern, central and eastern Europe, fossil fuels contributed more than two thirds (69%) of all fuels burned in combined heat and power plants and heat-only plants in 2020, as shown in Figure 3.

Figure 3. Gross EU heat production by fuel in combined heat and power and district heating plants, 2020

Source: ESTAT (2022).

Explore different chart formats and data here

Industry

Industrial sectors can also be important heat users. Industry currently accounts for a quarter of final energy use (see Figure 1), chiefly supplied by fossil fuels. Industrial heat demand accounts for about one third of all EU heating needs (EC, 2022c).

Even though official energy statistics do not capture comprehensively and consistently the final consumption of energy for heating and cooling per end-use sector and energy source (EC, 2022a), energy for both heating and cooling is consumed across industrial sectors, from the need for high-temperature heat in the metallurgical and ceramic industries[6], to the use of lower temperature steam and cooling agents in the food and textile industries.

Renewable energy sources in heating and cooling

In 2020, renewable energy sources accounted for only 23% of final energy used for heating and cooling from all sources in the EU. Despite this relatively small share, in absolute terms, most renewable energy used across the EU was consumed for heating and cooling due to the large demand for heating and cooling[7].

In the past 5 years, the share of renewable energy used for heating and cooling grew at a slower rate than it did from 2005 to 2015[8]. Despite this slower pace, at the EU level, the share by 2020 was still slightly higher than that expected for 2020 (22.4%) based on commitments made by Member States in 2010 in their national renewable energy action plans (see Figure 4).

Figure 4. Historical use of renewable sources for heating and cooling in the EU, 2005-2020, and 2020 NREAP levels

Notes: At the EU level, the actual share of renewable energy sources used for heating and cooling in 2020 (of 23.1%) was higher than the share expected for 2020 (of 22.4%) based on Member States’ national renewable energy action plans (NREAPs).

Source: EEA renewable energy data viewer.

Explore different chart formats and data here

Trends in the use of renewable energy sources for heating and cooling across end-use sectors provide two key insights. Firstly, the use of solid biomass has prevailed as main heating fuel. Solid biomass use for heating increased by over a third since 2005, accounting for 80% of all renewable energy used for heating and cooling in 2020 at the EU level[9]. A large proportion of this biomass was used by individual households in domestic heat stoves, with important possible ramifications extending to human exposure to air pollutants (EEA, 2019) and impacts on land carbon sequestration and biodiversity. Secondly, since 2005, the use of other renewable options for heating and cooling, such as heat pumps and solar thermal collectors, grew at a much faster rate than the use of solid biomass[10]. This indicates there is potential to deploy these technologies faster this decade (IEA, 2023).

Heat pumps Through their ability to extract useful renewable energy from a variety of sources, including from city subways, wastewater treatment plants, data centres and geothermal sources, modern reversable heat pumps using refrigerants with low or very low global warming potential are emerging as a flexible approach to decarbonising heating and cooling in buildings without directly producing greenhouse gas and air pollutant emissions during use. Heat pumps can also run with variable generation sources, such as rooftop solar photovoltaic modules, to help store excess renewable electricity as heat for later use or to help modern district heating and cooling networks to become more efficient by integrating other renewable and waste energy sources for heating and cooling. The EU aims to double the rate of uptake of individual heat pumps, to reach 10 million units over the next 5 years (EC, 2022b; EEA, 2022a).

Policy measures for heating and cooling

Improving energy efficiency can provide multiple benefits to society. If policymakers duly implement the ‘energy efficiency first’ principle and direct efforts to better insulating buildings, overall heating and cooling needs will fall. This, in turn, will reduce the need for investment in heating and cooling (EC, 2022c). Improving the efficiency of building envelopes can also reduce social inequalities and help alleviate energy poverty (EEA, 2022b). Boosting the energy performance of the building stock through higher annual renovation rates, coupled with more ambitious standards for the energy performance of buildings, as envisaged by the recent recast proposal of the Energy Performance of Buildings Directive, will play a significant role in decarbonising the heating and cooling of buildings by 2030. But energy efficiency measures alone will be insufficient to decarbonise heating and cooling while fossil fuels are still being used as the main energy source (Nijs et al., 2021).

Under the post-2020 legal framework, the national climate and energy plans and investment programmes of the Member States must demonstrate that they prioritise the ‘energy efficiency first’ principle to accelerate the rate and extent of building insulation works (EC, 2021c). For energy supply, several EU measures and proposals aim to increase the use of renewable sources for heating and cooling across all Member States by 2030. These measures aim to overcome market fragmentation, harmonise national heating and cooling decarbonisation efforts, and rapidly reduce gas use. One such measure is an indicative requirement for Member States to increase their national shares of renewable energy sources used for heating and cooling by 1.1 percentage points per year, on average (EU, 2018a). More recent proposals relate to mainstreaming renewable energy deployment in buildings to reach an indicative 49% renewable energy share in final energy use in buildings across the EU. If adopted, these proposals would increase the share of renewable sources in district heating and cooling by 2.1 percentage points per year, on average, until 2030. They would also require improvements in the efficiency of co-generation systems (EC, 2021b), doubling the deployment rate of heat pumps to reach 10 million units by 2027, and accelerating the implementation of geothermal and solar thermal heating to significantly cut demand for gas in heating and cooling (EC, 2022b). Successful decarbonisation strategies for buildings for this decade require thus a combination of more ambitious energy renovation measures and a faster switch to efficient, renewable and waste sources for heating and cooling. Such measures could also help to alleviate gas price volatility and reduce air pollutant emissions.

In industry, mature approaches, such as direct electrothermal heating, heat pumps or biogas, could already be used to replace gas in the short term for medium- and low-temperature industrial heating and cooling. However, replacing fossil fuels in high-temperature processes may require renewable hydrogen supply, which currently is still a scarce resource (IPCC, 2022). Since 2021, medium- and long-term climate mitigation efforts have been compounded by an increased sense of awareness of high gas prices and supply volatility that could affect industrial competitiveness (IEA, 2023). At the gas prices that prevailed across the EU in 2021 and 2022, the attractiveness of industrial gas substitutes, including renewable hydrogen supply, has improved considerably, strengthening the economic case of the EU moving away from fossil fuels (IEA, 2023, 2022).

Prospects and challenges for 2030

For the EU and its Member States, decarbonising heating and cooling represents a major challenge on the way to meeting climate targets for 2030 and 2050 and ensuring that fundamental energy needs, such as for residential heating, can be met more securely than they are today. However, national policymakers face very different challenges and opportunities in decarbonising heating and cooling, because the availability of sustainable energy resources and the demand for heating and cooling from buildings and industry vary significantly at the country and regional levels.

To rise to the challenge, Member States will have to assess the sustainable market potentials for national, regional and local renewable energy use and waste heat and cold recovery and devise replacement schemes for fossil-fuel heating systems to increase the deployment of renewable and waste sources for heating and cooling across all sectors. For that, Member States will need to set clear end-dates for fossil fuel subsidies across all energy markets and especially in heating.

In general, adhering to the ‘energy efficiency first’ principle (EC, 2021c) can reduce buildings’ heating and cooling needs significantly[11]. Prioritising energy efficiency measures would also help the sector to meet the EU Renovation Wave target — to reduce buildings’ energy use by at least 60% by 2030. But success depends on the ability of competent authorities to drive high insulation rates, deep-energy retrofits and circular renovation actions across all buildings, and to construct zero-emission buildings[12] (EC, 2020b; EEA, 2022a).

At the same time, without an urgent move away from heating systems that use fossil fuels, it is unlikely that the EU’s climate mitigation targets for 2030 will be met (Nijs et al., 2021). On the supply side, as illustrated in Figure 5, the use of renewable energy sources must increase at a much faster rate, to meet 40% or more of the EU’s heating and cooling demand by 2030 and a minimum of 45% across all market sectors (EC, 2020a, 2022a).

Successful responses to the specific strengths and weaknesses of national and regional decarbonisation pathways will also require policymakers to set strategic research agendas and foster innovation and learning from each other. Most importantly, to implement low-emission heat and cold supply systems cost-effectively, measures will have to target faster building renovation rates, to create nearly zero- and zero-emission buildings, and to substitute fossil fuels with renewable and waste heat and cold energy sources across all sectors (EC, 2022a).

Figure 5. Historical (2005-2020) and targeted (2030) shares of renewable energy sources in EU heating and cooling

Note: The 40% share of renewable sources in final energy use for heating and cooling corresponds to the REG and MIX scenarios of the Climate Target Plan figures document. Variations of this share are marginal in the other target-reaching scenarios.

Sources: EU (2020); ESTAT (2021).

Explore different chart formats and data here

The Scandinavian and Baltic EU countries, where average heating needs are higher because of climatic factors, had already reached high shares, of more than 50%, of renewable sources in final energy consumed for heating and cooling in 2020, by utilising biomass extensively. The widespread use of modern district heating systems in these countries can facilitate the integration of low-temperature heat from geothermal and solar thermal sources and from recovered waste heat. Portugal too had reached a high share of renewable heating and cooling, of 42%, by integrating a more even mix of renewable sources that includes heat pumps, solar thermal energy and solid biomass use for heating and cooling. Further opportunities exist in all EU countries to use diverse renewable and waste sources for heating and cooling and to capitalise on digitalisation for developing a more flexible, secure and integrated energy system that encompasses heating, electricity and mobility networks.

In central and eastern Europe, many urban district heating systems are old and marred with existential challenges, ranging from inefficient heat production to network losses and a strong fossil-fuel dependence (EPG, 2022). One of the main challenges for these systems is overcoming the problems resulting from poor maintenance and abandonment. While it is possible to modernise some of these systems to reduce their running costs and environmental footprints, doing so is not simple. Finding solutions will require careful analysis of economic and environmental trade-offs, including as regards potentially more sustainable alternatives. Options for upgrading older district heating systems can be complex and costly. It can be necessary to modernise boilers, heat exchangers, heat supply networks and system controls (for instance by installing smart sensors and digital technologies) to improve a system’s reliability and performance. Insulating pipes better to reduce unintended heat loss may also be required. Further measures can include densifying and expanding the network to serve more customers and achieve economies of scale, providing new services (such as cooling), incorporating new heat networks (including for waste heat) and diversifying to renewable sources that work well in combination (such as solar thermal and photovoltaic modules and heat pumps).

Biomass, as a limited resource, needs to be managed sustainably and used in the most beneficial way to increase land carbon stocks and ecosystem services. A generalised transition from fossil to biomass fuels in homes and district heating systems may exacerbate competition for biomass feedstock. Often, such feedstock can more optimally be used to substitute more carbon-intensive building materials or petrochemical feedstock (EEA, 2019; IPCC, 2022). Although sustainable biomass fuels are a renewable source of energy, trees and other vegetation also act as a land carbon sink, by absorbing carbon dioxide from the atmosphere. Therefore, demand for biomass resources, such as for heating, needs to be carefully balanced with the necessity to increase land carbon sinks, in line with the existing legal framework for greenhouse gas emissions and removals from land use, land use change and forestry (LULUCF) in the 2030 climate and energy framework (EU, 2018b). As safeguard, the European Commission has proposed further strengthening the sustainability requirements for biomass resources that count towards the EU’s renewable energy targets (EC, 2021a). Depending on the environmental impacts of biomass feedstock production and use, solar energy modules and heat pumps can offer more sustainable alternatives for decarbonising residential heating and cooling than the combustion of biomass.

No silver bullet to decarbonise buildings — thermal retrofitting during this decade must be matched by measures to replace fossil-fuel heating systems with zero-emission and low-carbon energy sources For buildings that use fossil fuels for heating and cooling, thermal retrofitting of the envelope is a key step towards decarbonising their energy use, but it is insufficient on its own. Further insulating such buildings helps to save energy and reduce the amount of fossil fuels used for heating and cooling. However, to successfully decarbonise the building sector in line with the EU’s climate commitments for 2030 and 2050, thermal retrofitting such buildings must be accompanied by a switch to renewables-based heating systems (Nijs et al., 2021). Policymakers can maximise the socio-economic, health and environmental co-benefits of renewable heating and cooling strategies by assessing the possible interactions and implications of specific energy pathways, prioritising neighbourhood and systemic solutions, and providing stakeholders and consumers with information that allows them to make optimal choices (EEA, 2022a, 2019).

Hot Weather Spells Trouble For Nuclear Power Plants In Europe

Enlarge this image toggle caption Kimmo Mantyla/AP Kimmo Mantyla/AP

Nuclear power plants in Europe have been forced to cut back electricity production because of warmer-than-usual seawater.

Plants in Finland, Sweden and Germany have been affected by a heat wave that has broken records in Scandinavia and the British Isles and exacerbated deadly wildfires along the Mediterranean.

Air temperatures have stubbornly lingered above 90 degrees in many parts of Sweden, Finland and Germany, and water temperatures are abnormally high — 75 degrees or higher in the usually temperate Baltic Sea.

That’s bad news for nuclear power plants, which rely on seawater to cool reactors.

Finland’s Loviisa power plant, located about 65 miles outside Helsinki, first slightly reduced its output on Wednesday. “The situation does not endanger people, [the] environment or the power plant,” its operator, the energy company Fortum, wrote in a statement.

Sponsor Message

The seawater has not cooled since then, and the plant continued to reduce its output on both Thursday and Friday, confirmed the plant’s chief of operations, Timo Eurasto. “The weather forecast [means] it can continue at least a week. But hopefully not that long,” he said.

Eurasto says customers have not been affected by the relatively small reduction in output, because other power plants are satisfying electricity demand. The power plant produced about 10 percent of Finland’s electricity last year.

The company also cut production at the Loviisa facility in 2010 and 2011, also due to warm water, but Eurasto said this summer’s heatwave has been more severe than previous ones.

Nuclear power stations in Sweden and Germany have also reduced production because of cooling problems, Reuters reported. A spokesperson for Sweden’s nuclear energy regulator told the wire service on Tuesday that the Forsmark nuclear power plant in Sweden had cut energy production “by a few percentage points.”

Cooling issues at nuclear power plants may get worse in the future. Climate change is causing global ocean temperatures to rise and making heat waves more frequent and severe in many parts of the world. A 2011 report by the Union of Concerned Scientists warned that warmer seas could affect the efficiency of nuclear power plants, noting:

“…during times of extreme heat, nuclear power plants operate less efficiently and are dually under the stress of increased electricity demand from air conditioning use. When cooling systems cannot operate, power plants are forced to shut down or reduce output.”

Sponsor Message

It’s not just warmer oceans that could spell trouble for nuclear power plants. Climate change is also producing more powerful storms and contributing to drought conditions, threatening facilities on coasts with wave and wind damage, and reducing the amount of water available to plants that cool their reactors with fresh water.

What is a heat wave? A heat wave is a period of abnormally hot weather generally lasting more than two days. Heat waves can occur with or without high humidity. They have potential to cover a large area, exposing a high number of people to hazardous heat. Heat can be very taxing on the body; learn more about the heat related illnesses that can occur.

Extreme heat also impacts our infrastructure – from transportation to utilities to clean water and agriculture. High heat can deteriorate and buckle pavement, warp or buckle railway tracks, and exceed certain types of aircraft operational limits. Electricity usage increases as air conditioning and refrigeration units in homes and offices work harder to keep indoors cooler. Transmission capacity across electric lines is reduced during high temperatures, further straining the electrical grid. Water resources are also strained as conventional power plants require large quantities of water for cooling and crops may need increased water consumption, and people increase water consumption to stay hydrated and cool. Heat can have lasting impacts as crops may be damaged, reducing production which leads to short supply and or increased cost to the farmers and consumers.

Stay Informed: Monitor local radio and television (including NOAA Weather Radio), internet and social media for information and updates.

Outdoor Activities Slow down. Reduce, eliminate or reschedule strenuous activities until the coolest time of the day. Those particularly vulnerable to heat such as children, infants, older adults (especially those who have pre-existing conditions, take certain medications, living alone or with limited mobility), those with chronic medical conditions, and pregnant women should stay in the coolest available place, not necessarily indoors.

Dress for the heat. Wear lightweight, loose fitting, light-colored clothing to reflect heat and sunlight.

Minimize direct exposure to the sun. Sunburn reduces your body’s ability to dissipate heat. Eating and Drinking Eat light, cool, easy-to-digest foods such as fruit or salads. If you pack food, put it in a cooler or carry an ice pack. Don’t leave it sitting in the sun. Meats and dairy products can spoil quickly in hot weather.

Drink plenty of water, non-alcoholic and decaffeinated fluids, even if you don’t feel thirsty. If you are on a fluid-restrictive diet or have a problem with fluid retention, consult a physician before increasing consumption of fluids.

Do not take salt tablets unless specified by a physician. Cooling Down Use air conditioners or spend time in air-conditioned locations such as malls and libraries.

Use portable electric fans to exhaust hot air from rooms or draw in cooler air.

Do not direct the flow of portable electric fans toward yourself when room temperature is hotter than 90°F. The dry blowing air will dehydrate you faster, endangering your health.

Take a cool bath or shower. Check on Others Check on older, sick, or frail people who may need help responding to the heat. Each year, dozens of children and untold numbers of pets left in parked vehicles die from hyperthermia. Keep children, disabled persons, and pets safe during heat waves

For more heat health tips, go to the Centers for Disease Control and Prevention

Children and Heat Vulnerability (Source: The Impacts Of Climate Change On Human Health In The United States: A Scientific Assessment) Newborns, infants, and young children are particularly vulnerable to heat-related illness and death. Their bodies are less able to adapt to heat than are adults.

Children under four years of age experience higher hospital admissions for respiratory illnesses during heat waves.

The effects are more severe on children because their bodies warm at a faster rate than adults. Protect and prepare: Keep children cool by having them drink plenty of water, take lots of breaks, wear light-colored and lightweight clothing, and limit playing outdoors to cooler times of the day. Make sure fluids are not very cold or high in sugar/sweetener content. Heat Safety in Vehicles

Even on mild days in the 70s, studies have shown that the temperature inside a parked vehicle can rapidly rise to a dangerous level for children, pets and even adults. Leaving the windows slightly open does not significantly decrease the heating rate. A dark dashboard or car seat can quickly reach temperatures in the range of 180°F to over 200°F. These objects heat the adjacent air by conduction and convection and also give off long wave radiation, which then heats the air trapped inside a vehicle. Click here to learn more and follow these tips to ensure children’ s safety. Touch a child’s safety seat and safety belt before using it to ensure it’s not too hot for the child

Never leave a child unattended in a vehicle, even with the windows down, even for just a minute

Teach children not to play in, on, or around cars. They could accidentally trap themselves in a hot vehicle.

Always lock car doors and trunks–even at home–and keep keys out of children’s reach.

Always make sure children have left the car when you reach your destination. Don’t leave sleeping infants in the car.