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Global warming is already impacting respiratory health in many ways. This influence will likely worsen in the coming years. The risks of extreme heat, dust storms and forest fires are rising. Global warming also affects the levels of circulating aeroallergens by extending the pollen season and facilitating the growth of fungi producing mycotoxins. It will promote conditions such as thermal inversions and photochemical smog, which worsen air quality. All these factors can aggravate pre-existing respiratory diseases and increase the risk of respiratory conditions in previously healthy individuals.

Heat, climate change and respiratory disease

Among many other health outcomes, exposure to elevated temperatures can lead to respiratory symptoms. When coupled with increasing humidity, heat makes breathing more difficult even for healthy individuals, resulting in airway irritation and coughing in individuals with allergic rhinitis, as well as bronchoconstriction and coughing in individuals with asthma (Hayes et al., 2012; Khosravi et al., 2014; Andersen et al., 2023). Specifically, increases in indoor temperatures worsen COPD symptoms (McCormack et al., 2016) and shortness of breath, emergency calls for respiratory symptoms and apnoea (Tham et al., 2020). No consistent reporting of heat-related mortality exists in Europe. According to information held by various databases on natural disasters and catastrophes, heatwave events were responsible for 95% of fatalities caused by weather- and climate-related extreme events in  member countries between 1980 and 2023. This corresponds to over 240,000 deaths over that period (EEA, forthcoming). The proportion of these deaths related to respiratory causes is unclear.

The global mean air temperature was the warmest on record between 2013 and 2023, and around 1.2°C warmer than the pre-industrial level. European land temperatures, as summarised by the relevant EEA indicator, have increased even faster over the same period (by over 2.1°C). Hot days with temperatures above 30°C have increased throughout Europe and may increase fourfold by the end of the century under a high-emissions scenario. The largest absolute increases are predicted for southern Europe. The number of tropical nights (those with a minimum temperature of at least 20°C) has increased throughout Europe. Southern Europe may experience up to 100 tropical nights per year by the end of the century under a high-emissions scenario. Similarly, European residents’ exposure to heatwaves has increased significantly, particularly for those at high risk, like the elderly. However, heat-related mortality did not follow a similarly upwards trend from 2000 to 2020, possibly on account of the implementation of protective policies and improvements to health systems across Europe (WHO, 2021). 

Prospectively, prolonged waves of extreme heat are projected to increase substantially across Europe under all considered scenarios and especially in southern regions. The warmest three-day mean temperature is projected to increase by at least 1.5°C and potentially by as much as 6.5°C. And the duration of extreme humid heat conditions is also projected to increase substantially across Europe, with the largest increase in southern Europe (EEA, 2021a).

Allergenic pollen, climate change and respiratory disease

Some types of pollen grains can trigger an immune response in the respiratory tract. In Europe, grasses  are the major cause of allergic reactions, along with birch trees in north, central and eastern Europe, and olive trees and cypress in the Mediterranean regions. Allergenic pollen is also produced by several herbaceous plants like ragweed, a highly allergy-inducing invasive species in Europe (Schaffner et al., 2020). Upon exposure to pollen, the immune system may produce antibodies specific to pollen allergens, triggering cascading effects causing airway inflammation and bronchoconstriction (Liu et al., 2024; Simpson et al., 2005). Children’s immature immune systems are more prone to overreacting to environmental triggers such as allergens (Shimizu et al., 2023). The impact on human health is primarily evident in allergic diseases like allergic rhinitis, rhino conjunctivitis and bronchial asthma. Studies suggest an association between pollen and COPD aggravation, including mortality in Europe, though the evidence is still inconclusive (Brunekreef et al., 2000; Cirera et al., 2012; Idrose et al., 2022). The association between certain types of pollen such as grass and birch and asthma exacerbation and/or hospitalisation is clearer, particularly in children (Shrestha et al., 2021; Guilbert et al., 2018; Lowe et al., 2012).

No reliable estimates of the health burden of pollen allergy on respiratory health in Europe exist due to the complex nature of allergic diseases, the many types of allergenic pollens and a lack of research. For example, the prevalence of birch pollen sensitisation in Europe is estimated to range between 8% and 16% (Biedermann et al., 2019), but there are no current robust European figures for weed and grass allergies, which are thought to be much more prevalent. A relatively old study from 2007 estimated the prevalence of pollen allergy in the European population at 40%, making it one of the most common allergens in Europe  (D’Amato et al., 2007).

The prevalence of pollen-induced allergies has increased in Europe over the past few decades, though it is unclear why (Forkel et al., 2020; Dramburg et al., 2024). Leading theories include improved hygiene, increased antibiotic use and vaccination, along with changes in lifestyle, dietary habits and air pollution (D’Amato, 2020; Becker et al., 2021; de Weger et al., 2021). In addition, climate change is affecting exposure to pollen and allergic sensitisation in several ways. Over the last 20 years, the duration of the pollen season has increased (on average by 0.9 day per year), along with pollen load (Ziska et al., 2019).

The onset of pollen season is happening earlier in the year. Meanwhile, warmer conditions and elevated atmospheric CO2 concentrations are increasing the concentrations of pollen and allergens in the air, as well as the allergenicity of the pollen itself. This increases the risk for allergic reactions (Beggs, 2015; Ziska et al., 2019). Altered humidity conditions, weather extremes and thunderstorms during the pollen season, all of which are exacerbated by climate change, cause higher pollen and allergen concentrations in the air. This leads to more severe allergic reactions and asthma attacks (Shea et al., 2008; Wolf et al., 2015; D’Amato, 2020). Lastly, global warming and the associated lengthening of the growing season is facilitating a northward migration of invasive plant species in Europe, including those which release allergenic pollen like ragweed (Vogl et al., 2008; Chen et al., 2018). In the future, the impacts of climate change on pollen seasons, concentrations and allergenicity are expected to lead to increased exposure of the European population to pollen and aeroallergens. This increases the likelihood of new allergic sensitisations (de Weger et al., 2021) and asthma, along with worsening the latter’s symptoms (Anderegg et al., 2021).

Green infrastructure in cities, while useful as an adaptation measure to climate change, may also increase pollen loads and allergic reactions (Cheng and Berry, 2013). A case study on 18 green spaces in Brussels demonstrated that the allergenic potential of urban parks is expected to double, due to combined changes in the duration of the pollen seasons, the allergenicity of pollen and the sensitisation rates of the population (Aerts et al., 2021). Considering suitable tree species for urban environments is crucial when designing climate adaptation measures and engaging in spatial planning to avoid exacerbating allergy risks.

Wildfires, climate change and respiratory disease

Wildfires — including forest fires — are essential for many ecosystems. They help with forest renewal, control insect and disease damage, and reduce the build-up of fuel and thus future fire intensity. However, frequent and large-scale fires have negative impacts, including fatalities in populated areas, economic damage and severe episodes of air pollution. Wildfire smoke increases mortality, including from COPD (Doubleday et al., 2020) and the risk of asthma-related hospitalisations (Pratt et al., 2019). With regard to respiratory mortality, one study found medium-sized fires are associated with an increase of 16.2% in the number of daily respiratory deaths (Analitis et al., 2012;Weilnhammer et al., 2021). In the EU-27, an estimated 1,483 and 1,080 premature deaths in 2005 and 2008 respectively were attributable to PM2.5 originating from vegetation fires (Kollanus et al., 2017). Following a series of wildfires in 2002, cases of respiratory diseases increased 20-fold near Vilnius, Lithuania (Pereira, 2015). Similarly, increases of respiratory morbidity and symptoms have been observed in relation to wildfires in Sweden (Tornevi et al., 2021) and Portugal (Santos et al., 2015).

In the Mediterranean area, specifically southern France, Greece, Italy, Portugal and Spain (EUMED5) — traditionally the European countries most affected by wildfires — the burnt area has slightly decreased since 1980. However, there is large interannual variability strongly determined by meteorological conditions. For other European countries, data are available from 1992. More countries suffered larger forest fires than ever recorded in 2018, including in central and northern Europe, regions not typically affected by fires in the past. For instance, Sweden experienced its worst-ever fire season in 2018 and required international fire-fighting assistance. Many of the recent extreme fire episodes and devastating fire seasons in Europe were driven by severe weather conditions, with record droughts and heatwaves occurring in the spring and summer of 2017 and 2018 (EEA, 2021b).

Available data suggest 36,000 people were affected by wildfire exposure in Europe in 2023. Nearly 50,000 people on average each year between 2010 and 2012 in the members and cooperating countries lived in areas assessed as burned by wildfires. The average population living within 5km of burnt areas was nearly 7.08 million people each year. These numbers were on average almost 119,000 and 10.83 million, respectively between 2017 and 2019. The highest proportions of the population living within 5km of burnt areas were in regions of Portugal, Spain, Italy and Albania (EEA, 2024). Prospectively, climate change will continue increasing the frequency and intensity of wildfire events, as well as the duration of the high wildfire risk season. This will occur mainly in the Mediterranean countries, but also in temperate regions (El Garroussi et al., 2024). The current rate of population exposure to wildfire smoke (less than 10 per 1,000 people exposed from 1981 to 2010) is projected to increase to between 12 and 20 per 1,000 people across Europe in the years 2071-2100 (Forzieri et al., 2017).

What the EU is doing about climate change and heat, allergenic pollen and wildfires

The EU has implemented several key policies and regulations to address climate change, energy poverty and the built environment, as well as the exposure featured here (heat, pollen and wildfires).

A detailed account of EU policy on climate change adaptation in relation to health is provided on the European Climate and Health Observatory. The European Green Deal is the main policy framework which has covered climate change mitigation and adaptation over the past few years. This set out a growth strategy to transform the EU into a fair, prosperous and resource-efficient society with net zero greenhouse gas emissions in Europe by 2050. Regulation 2022/2371 on serious cross-border threats to health aims to strengthen health security capacities and resilience to health threats, including those of environmental origin and caused or worsened by factors associated with climate change. The Eight Environmental Action Programme, set out in May 2022 by the European Commission, aims to ensure that EU climate and environmental laws are effectively implemented. The European Climate Law translates the European Green Deal’s net zero target into legislation, requiring Europe’s economy and society to be climate-neutral by 2050. In addition, in February 2021, the Commission outlined the EU Strategy on Adaptation to Climate Change. This established a long-term vision for the EU to become a climate-resilient society, one which is to be fully adapted to the unavoidable impacts of climate change by 2050. The actions taken under this strategy may make a crucial contribution to the prevention of the respiratory impacts of climate change (EEA, 2023b; EC, 2024). In addition, the EU Mission on Adaptation to Climate Change aims to guide at least 150 communities through effective climate change adaptation pathways by 2030.

On heat, some EEA member countries (16 as of 2020) have national or federal heat-health action plans (Martinez et al., 2022), while others have subnational and local plans for preventing health impacts from heat (Vanderplanken et al., 2021). Heat-health action plans are proven to be effective (WHO, 2021). Preventing heat impacts on respiratory health is a common priority area of national climate change adaptation policies in the ’s 38 member and collaborating countries, listed in a recent report as the third most frequent policy (ECHO, 2022).

On allergenic pollen, the EU’s Copernicus system provides pollen forecasts for six of the most allergenic species, based on data from the European Aeroallergen Network and its own atmospheric data. In addition, the EU is funding research on automatic pollen detection to increase data coverage and provide better information to allergy sufferers.

On wildfires, the EU Forest Strategy for 2030 sets the basis for increased forest fire prevention and climate resilience. Guidelines on land-based wildfire prevention call for vegetation management to avoid fuel accumulation on the ground. Forest fire-fighting and prevention efforts are supported by the European Forest Fire Information System  (EFFIS) in the EU and neighbouring countries. The expert group in forest fires and the EU civil protection mechanism provide additional support in this area.

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