Vulnerabilities - Overview

Direct consequences of climate change for human health in the Netherlands are a higher vulnerability to heat stress in case of extremely hot summers and the probability of large numbers of casualties in a single flood episode (1).

Indirect consequences of climate change for human health are: vector-transmitted diseases (increase in malaria (unlikely); increase in Lyme disease (medium likelihood); diseases linked to air quality (increase in summer smog (ozone and particulates) (likely); reduction in winter smog (particulates) (medium likelihood));  allergies (increase in hay fever (likely);  increase in house-mite allergy (unknown)); increase in water-related diseases (medium likelihood); increase in food-related diseases (unlikely); increased exposure to UV-related disorders (medium likelihood) (1). 

Many of the indirect effects are related to changes in behaviour: people are expected to go outside more often and for longer because (on average) it will become warmer and they will spend more time on outdoor leisure and recreation activities. Exposure to UV radiation, air pollution and pollen, water-borne diseases (cyanobacteria, amoebae) and Lyme disease will increase as a result (1).

The ozone layer above the Netherlands will probably recover more quickly because of climate change, thus reducing exposure to UV radiation. Although climate change has an influence on diseases, and thus on human health, other factors have a much greater impact. Examples include frequent travel abroad, which makes it much easier for diseases to spread, as well as infectious diseases, quality of the indoor environment, lifestyle and eating patterns (obesity and cardiovascular disease) (1).

The magnitude of the health effects in the Netherlands still seems to be limited, but it is uncertain how this could develop in worst case scenarios (1). Risk groups in the population (such as the elderly, children or people with asthma) might experience stronger effects (a greater burden of disease) (2).

Vulnerabilities - Cold stress

The optimum temperature for health in the Netherlands (the average temperature with the lowest mortality) is 16.5°C… The probability of excess mortality during periods of extreme cold (13% or an average of 47 people per day, mainly elderly) will slightly decrease. Based on the temperature-mortality relationship, it is supposed that the increasing mortality in the summer will possibly be compensated for by a decreasing mortality during the winter (2).

Most European countries have between 5 and 30 % higher death rates in winter than in summer. Winter‑related mortality in many European populations has declined since the 1950s (6). Cold days, cold nights and frost days have become rarer, but explain only a small part of this reduction: improved home heating, better general health and improved prevention and treatment of winter infections have played a more significant role (7).

Vulnerabilities - Heat stress

Heat waves combined with urban heat islands (12) can result in large death tolls with the elderly, the unwell, the socially isolated, and outdoor workers (13) being especially vulnerable. Heat waves thus pose a future challenge for major cities (14).

During the heat waves of 1982, 1983, 1990, 1994, 1995 and 1997, the extremely high temperatures resulted in an average of 40 additional deaths per day in the Netherlands. The heat wave of August 2003 lasted about 2 weeks. Compared with the mortality rate during a normal August (with a mean temperature of about 22⁰C), Statistics Netherlands concluded that about 400–500 extra deaths occurred due to the extreme heat in that period. Calculations for the Netherlands have demonstrated that the increased air pollution (ozone, particulate matter) during heat waves is responsible for about 25–40% of the registered ‘heat wave mortalities’ (2).

Research has revealed that part of the excess mortality during heat waves must be viewed as ‘only a slight forward displacement of death’. As a result of this forward displacement, a temporary fall in mortality is often observed in the weeks following a heat wave. The other part could be viewed as excess mortality with substantial loss in life years. Unfortunately, little is known about the ratio between these two categories (2).

Thermal discomfort

Thermal discomfort will substantially increase in The Netherlands. This was concluded from an analysis of 4 climate change scenarios for 2050 compared to 1976 – 2005 (26). The scenarios represent the bandwidth of climate change that is considered likely in the Netherlands according to the Royal Netherlands Meteorological Institute (the bandwidth refers to the KNMI 2006 scenarios but hardly differs from the most recent KNMI 2014 scenarios). Thermal discomfort is governed by a number of factors, including air temperature, the human body’s net radiation, wind speed, humidity, human activity, and clothing.

In the analysis climate characteristics were used to calculate an index that describes thermal discomfort. This index is the so-called physiological equivalent temperature (PET) (27). The PET index is defined as the air temperature at which, in a typical indoor setting (without wind and solar radiation), the heat budget of the human body is balanced with the same core and skin temperature as under the complex outdoor conditions to be assessed. As such, PET enables a layperson to compare the integral effects of complex thermal conditions outside with his or her own experience indoors. The defined classes indicate slight heat stress (PET: 23–29°C), moderate heat stress (PET: 29–35°C), strong heat stress (PET: 35–41°C), and extreme heat stress (PET: 41°C or higher).

According to the analysis, the amount of hours with heat stress will substantially increase in the future, with most scenarios resulting in a doubling of the hours with heat stress (PET>23°C). The number of hours with strong to extreme heat stress (PET > 35°C) will increase by a factor 1.9 – 5, depending on the scenario. While the class of the most intense heat stress (PET > 41°C) is currently absent, it may appear for 14h per year in the most extreme scenario considered by 2050 (26).

There are ways to circumvent this increase of thermal discomfort via interventions in urban planning (28). For instance, the construction of parks with sufficient water supply and tall, isolated, shade-providing trees that allow for adequate ventilation are recommended for planning. 

The urban heat island of Amsterdam

Cities are generally warmer than their surrounding rural areas. The urban fabric and surface materials capture and store incoming solar radiation during daytime and release the heat more slowly during the night than rural areas (30). High buildings can decrease wind speed and thus slower cooling of building and street surfaces. Evapotranspiration in cities is less due to lack of vegetation and surface moisture, leaving more thermal energy available to heat the city (31). Heat production by citizens, office buildings, industry, and traffic further increase air temperatures (32). Water bodies may limit warming in the early summer (when the water is still relatively cold), but may suppress cooling later in summer (33). The impact of all these factors on urban temperature is called the urban heat island effect.

An analysis of temperature observations indicates that the urban heat island effect is a nocturnal phenomenon in The Netherlands, when it exceeds 2°C. The effect occurs in all seasons, but is most significant in the summer (36).

The urban heat island effect will change because climate changes and as a result of urban development. The combined effect of these factors has been assessed for Amsterdam for 2040. Currently, maximum daytime temperatures are over 3 °C warmer in the city than in the surrounding countryside on moderately warm summer days. On warm days the difference can be up to 5 °C (29). Similar results were found in previous studies for other Dutch cities (34), and cities in other countries (35).

Projections of climate change and urban development in 2040 indicate that the urban heat island effect in Amsterdam may strongly increase due to a combination of urban development and more frequent extreme climatic events such as heat waves. The impact of average climate change will be small: an increase in average maximum temperature in summer of 1-3 °C, as projected in Dutch climate scenarios for 2050, will only lead to a marginal increase in urban temperatures of about 0.1-0.3 °C for inner urban locations. It is the combined effect of more frequent extreme hot days and lateral increase of urbanization that counts. Spatial planning strategies that reduce the lateral spread of urban development will thus greatly help to limit a further increase in the intensity of the urban heat island effect. The impact of compact urbanization on the urban heat island effect is much smaller than the impact of adding new residential areas to the city (29).  

The urban heat island of Utrecht

For the city of Utrecht, an urban heat island (UHI) up to 3.1°C was measured (37).

Vulnerabilities - Heat stress versus cold stress

Projections have been made of changes in cold-related and heat-related mortality in the course of this century for the Netherlands. Climate change is expected to first decrease total net mortality in the Netherlands due to a dominant effect of lowered cold-related mortality, but this reverses over time, in the second half of this century, under high warming scenarios. A dominance of more heat-related mortality occurs in the projections for 2085, but only if the urban heat island effect is considered. This dominance is less pronounced when the additional warming in the largest Dutch cities is not accounted for. This observation highlights the importance of including the additional warming under climate change caused in cities by the urban heat island effect in studies that examine the potential effects of climate change on human mortality (39). 

Vulnerabilities - Skin cancer

The recovery of the ozone layer might well be delayed at the two poles (by several decennia), while at temperate latitudes it might be enhanced (recent IPCC report). In this way, health will be indirectly affected as a result of increased or decreased exposure to ultraviolet (UV) radiation. Furthermore, if there is an increase in warmer and drier summers, the chances of a greater exposure to sunlight and UV radiation (staying outside and in the sun more often) will increase the health risk. Exposure to UV radiation can lead to cataracts, skin cancer, and a weakening of the immune system (2).

Vulnerabilities - Food poisoning

Climate change can affect the prevalence of diseases such as salmonella poisoning following the consumption of infected food because the transmission and formation of this type of infection is directly temperature-dependent and, therefore, also climate-dependent. In the Netherlands, but also in other countries, significant effects of this have already been demonstrated. However, it is unlikely that these effects will be very large in the Netherlands due to the high standards of hygiene (2).

Vulnerabilities - Toxic algae blooms

Climate change could lead to a strong growth in the demand for recreational and nature areas. However, the increasing temperature might lead to a deterioration in the quality of the swimming water (if no extra management measures are taken) due to, for example, an increased blooming of (toxic) blue algae; this can pose a threat to the health of swimmers (2).

In temperate seas such as the North Sea harmful (toxic) algal blooms will probably increase as a result of climate change. Micro algae form the basis of the marine food chain. However, toxin-producing species may seriously disrupt the food web and lead to fish kills and human intoxication. Future toxic phytoplankton blooms may further devaluate ecosystem deliverables such as fish production or recreational use (8).

Vulnerabilities - Mosquito-borne diseases

Experts argue that the chance of a large-scale malaria epidemic in the Netherlands as apartial result of climate change is extremely small, mainly due to the excellent health care facilities in the Netherlands and preventative measures that can be taken (2).

Vulnerabilities - Tick-borne diseases

Between 1994 and 2001, the estimated number of tick bites in the Netherlands doubled from 30,000 to 61,000. The number of patients with a bull’s-eye shaped rash on the skin as an early symptom of Lyme disease also increased by about a factor of two, which indicates that the risk of infection is rapidly increasing. The increasing popularity of outdoor recreation is believed to be one of the most important causes (2,11).

Lyme disease could occur more frequently because warmer and wetter winters and earlier springs ensure an extension of the transmission period. In addition, climate change could lead to more outdoor recreation in the Netherlands and, hence, a greater risk of infection. The possible increase in Lyme disease cannot yet be estimated in quantitative terms (2). In 2011 it was concluded from research carried out by Wageningen University that 15% of the ticks in the Netherlands carries the bacteria that causes Lyme disease. This is more than the 10% average in the rest of Europe, probably due to the relatively warm climate (especially warm winters).

Vulnerabilities - Sand-fly-borne diseases

Leishmaniasis is a protozoan parasitic infection caused by Leishmania infantum that is transmitted to human beings through the bite of an infected female sandfly. Sandfly distribution in Europe is south of latitude 45⁰N and less than 800 m above sea level, although it has recently expanded as high as 49⁰N. Currently, sandfly vectors have a substantially wider range than that of L infantum, and imported cases of infected dogs are common in central and northern Europe. Once conditions make transmission suitable in northern latitudes, these imported cases could act as plentiful source of infections, permitting the development of new endemic foci. Conversely, if climatic conditions become too hot and dry for vector survival, the disease may disappear in southern latitudes. Thus, complex climatic and environmental changes (such as land use) will continue to shift the dispersal of leishmaniasis in Europe (9).

Vulnerabilities - Water-borne diseases

It is not very likely that climate change and temperature rise in the Netherlands will contribute to any great extent to diseases related to water quality. However, the following health effects might occur (2,3):

• effects caused by the increasing growth of – and exposure to – microbiological pollutants in the coastal, surface, and recreational and drinking water in the Netherlands; for example, blue algae or botulism;
• effects of pathogenic micro-organisms which up until now have caused little or no problems, such as amoebae, particularly during warm summers;
• effects of pathogenic micro-organisms from less developed areas (such as the cholera bacteria).

Increased precipitation, runoff and storm water overflow lead to more peak concentrations of waterborne pathogens in surface water. Peak concentrations strongly determine the infection risk through drinking water consumption (3).

Vulnerabilities - Air quality

There are great uncertainties in the effects of climate change on air pollution. This is particularly true for particulate matter. Literature is not conclusive on the extent of the ozone increase and for particulate matter not even on the sign of the effect. These uncertainties complicate the development of adaptation strategies (4).

Regarding ozone, concentrations will probably increase in polluted areas, especially during pollution events (5). Hence, peak concentrations are predicted to increase. This probably also holds for particulate matter: the increase in stagnant weather conditions in summer and the decrease in wet deposition efficiency will probably increase the particulate matter concentrations in a changing climate. Since high pollutant concentrations are thought to have caused increased death during the summer of 2003, this effect is of great concern (4).

Furthermore, air pollution can also cause severe lung diseases and cancer, resulting in reduced life times (4).

Summer smog and ozone

Climate change in the Netherlands results in an increase in the number of summer days, with the result that the probability of smog formation will increase. Another phenomenon that is in part associated with climate change, is the increase in the background concentration of ozone in the entire Northern Hemisphere. This significant increase has also been observed in the Netherlands. In the absence of a threshold value for effects, an increase in this background concentration will have a direct negative influence on the health. This impact is difficult to estimate quantitatively (4).

Winter smog and particulate matter

In the winter, during stable cold weather with frost, periods can occur in which there is a strong increase in the levels of fine particles for prolonged periods (winter smog) and during which the negative health effects of this form of air pollution increase. If Dutch winters become on average less cold due to climate change, then the chance of winter smog could decrease. However, in the future, extremely cold periods can still occur, and it is during such periods in particular that the chances of winter smog are much greater.

Allergies - Pollen and hay fever

Pollen-related allergic diseases may well account for 10–20% of allergic diseases in Europe. …  Climate change in the Netherlands and its possible effect on pollen production can therefore have a direct negative effect on allergic conditions such as hay fever and asthma and on the number of patients affected by these diseases. Although an effect of climate on pollen seems likely, there are no quantitative data to predict the size of this (4).

House dust mite

Their numbers increase considerably during the autumn in particular due to the higher indoor humidity. Although a climate effect on the house dust mite is likely, no quantitative data are available to predict the size ofthe effect (4).

Vulnerabilities in cities

It is thought that extreme levels of air pollution might be closely associated with urban heat islands (5). The urban heat island effect comprises a higher temperature and different atmospheric layering in cities than in their surroundings. This is due to concentrated cultivation, which affects the dispersion and ventilation of air pollutants, and the anthropogenic heat production in cities (4).

It is unknown how climate change impacts the urban meteorology, urban mixing layer height and stratification and how these impact the air pollutant concentrations in and downwind of the cities. In the research to climate adaptation, it is necessary to understand future air quality in urban areas for development of adaptation strategies (4).

Vulnerabilities - Floods

Floods are the most common natural disaster in Europe. The adverse human health consequences of flooding are complex and far-reaching: these include drowning, injuries, and an increased incidence of common mental disorders. Anxiety and depression may last for months and possibly even years after the flood event and so the true health burden is rarely appreciated (10).

Effects of floods on communicable diseases appear relatively infrequent in Europe. The vulnerability of a person or group is defined in terms of their capacity to anticipate, cope with, resist and recover from the impact of a natural hazard. Determining vulnerability is a major challenge. Vulnerable groups within communities to the health impacts of flooding are the elderly, disabled, children, women, ethnic minorities, and those on low incomes (10).

Adaptation strategies - the Netherlands

Air polution

The uncertainties on the effects of climate change on air pollution complicate the development of adaptation strategies since it is not clear how urgent the problems will be (4).

Human adaptation to increased air pollution may not be possible since physiologic mechanisms to decrease susceptibility to air pollution are limited (5). Adaptation as a risk management strategy can, however, also focus on the reduction of the effects of changing climate conditions on urban heat islands and air pollution (4).

Heat stress

Several measures have been thought of to reduce the urban heat island effect, which are in the first place meant for reducing temperatures in the city. Examples are the use of more energy efficient or sustainable technologies in the cities and the construction of water and vegetation rich areas. The construction of vegetation rich areas is in the first place effective for cooling but could also enhance uptake of ozone from the air to reduce ozone concentrations. The type of vegetation should therefore be chosen carefully to optimize the efficiency of stomatal ozone uptake and to reduce the efficiency of VOC emissions at future climate conditions.

In 2007, a National Heat Plan was prepared (1).

A list of possible adaptation measures for heat stress has been published for measures to buildings and (parts of) cities (25):

• Building: Insulate buildings; cooling systems (e.g. heat pumps); sun screens, blinds and shutters; provisions for heat disposal (e.g. chimneys); building orientation (reduce sun exposure); heavy building materials (high solar thermal mass); green roofs (i.e. plant cover); green facades (i.e. plant cover); increased reflecting levels of roofs (albedo); insurances (building owner); cooling (air conditioning).
• Street/quarter/city level: Open water, fountains, etc.; vegetation (cooling due to evaporation); high albedo pavement instead of asphalt; creating optimal shading in building orientation, compact building and (big leaf) trees; orientation and profile of streets regarding wind direction (affecting wind speed and urban ventilation); replacement of vulnerable groups; monitoring and inspection; warning systems and disaster contingency plans; wetting streets and roofs; access to/capacity of medical care; information campaigns; move to cooler areas.

A study for Amsterdam has shown that the impact of compact urbanization on the urban heat island effect is much smaller than the impact of adding new residential areas to the city (29).

Adaptation strategies - General - Heatwaves

The outcomes from the two European heat waves of 2003 and 2006 have been summarized by the IPCC (15) and are summarized below. They include public health approaches to reducing exposure, assessing heat mortality, communication and education, and adapting the urban infrastructure.

1. Public health approaches to reducing exposure

A common public health approach to reducing exposure is the Heat Warning System (HWS) or Heat Action Response System. The four components of the latter include an alert protocol, community response plan, communication plan, and evaluation plan (16). The HWS is represented by the multiple dimensions of the EuroHeat plan, such as a lead agency to coordinate the alert, an alert system, an information outreach plan, long-term infrastructural planning, and preparedness actions for the health care system (17).

The European Network of Meteorological Services has created Meteoalarm as a way to coordinate warnings and to differentiate them across regions (18). There are a range of approaches used to trigger alerts and a range of response measures implemented once an alert has been triggered. In some cases, departments of emergency management lead the endeavor, while in others public health-related agencies are most responsible (19).

2. Assessing heat mortality

Assessing excess mortality is the most widely used means of assessing the health impact of heat-related extreme events.

3. Communication and education

One particularly difficult aspect of heat preparedness is communicating risk. In many locations populations are unaware of their risk and heat wave warning systems go largely unheeded (20). Some evidence has even shown that top-down educational messages do not result in appropriate resultant actions (21).

More generally, research shows that communication about heat preparedness centered on engaging with communities results in increased awareness compared with top-down messages (22).

4. Adapting the urban infrastructure

Several types of infrastructural measures can be taken to prevent negative outcomes of heat-related extreme events. Models suggest that significant reductions in heat-related illness would result from land use modifications that increase albedo, proportion of vegetative cover, thermal conductivity, and emissivity in urban areas (23). Reducing energy consumption in buildings can improve resilience, since localized systems are less dependent on vulnerable energy infrastructure. In addition, by better insulating residential dwellings, people would suffer less effect from heat hazards. Financial incentives have been tested in some countries as a means to increase energy efficiency by supporting those who are insulating their homes. Urban greening can also reduce temperatures, protecting local populations and reducing energy demands (24).

The cooling effect of small urban water bodies, like ponds or canals, can be considered negligible, model experiments for Dutch waters in the urban environment have shown (38).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for the Netherlands.

1. Ministry of Housing, Spatial Planning and the Environment (2009)
2. Bresser (2006)
3. Schijven and De Roda Husman (2005)
4. Van Dijk et al. (2009)
5. Ebi and McGregor (2008), in: Van Dijk et al. (2009)
6. Kunst et al. (1991); Lerchl (1998); Carson et al. (2006), in: EEA, JRC and WHO (2008)
7. Carson et al. (2006), in: EEA, JRC and WHO (2008)
8. Peperzak (2005)
9. Semenza and Menne (2009)
10. Hajat et al. (2003)
11. Knols and Takken (2007)
12. Basara et al. (2010); Tan et al. (2010), in: IPCC (2012)
13. Maloney and Forbes (2011), in: IPCC (2012)
14. Endlicher et al. (2008); Bacciniet al. (2011), both in: IPCC (2012)
15. IPCC (2012)
16. Health Canada (2010), in: IPCC (2012)
17. WHO (2007), in: IPCC (2012)
18. Bartzokas et al. (2010), in: IPCC (2012)
19. McCormick (2010b), in: IPCC (2012)
20. Luber and McGeehin (2008), in: IPCC (2012)
21. Semenza et al. (2008)), in: IPCC (2012)
22. Smoyer-Tomic and Rainham (2001), in: IPCC (2012)
23. Yip et al. (2008); Silva et al. (2010), both in: IPCC (2012)
24. Akbari et al. (2001), in: IPCC (2012)
25. Runhaar et al. (2012)
26. Molenaar et al. (2016)
27. Deb and Ramachandraiah (2010), in: Molenaar et al. (2016)
28. Müller et al. (2014), in: Molenaar et al. (2016)
29. Koomen and Diogo (2017)
30. Oke (1982, 1995); Svensson (2004), all in: Koomen and Diogo (2017)
31. Akbari et al. (2001); Jusuf et al. (2007), both in: Koomen and Diogo (2017)
32. Hinkel and Nelson (2007); Sailor and Lu (2004), both in: Koomen and Diogo (2017)
33. Steeneveld et al. (2014), in: Koomen and Diogo (2017)
34. Steeneveld et al. (2011); Wolters et al. (2011); Heusinkveld et al. (2014); Van Hove et al. (2011), all in: Koomen and Diogo (2017)
35. Hart and Sailor (2009); Giannaros and Melas (2012), both in: Koomen and Diogo (2017)
36. Rahimpour Golroudbary et al. (2018)
37. Dirksen et al. (2019)
38. Jacobs et al. (2020)
39. Botzen et al. (2020)