Environmental Essay no.29 – Adapting to the Climate of the Future

Although the risk of extreme heat waves is limited in Denmark, we may have to set up systems to handle the health problems resulting from a warmer and moister climate. There may be a need to monitor exposed groups – mostly the elderly, but also people suffering from ailments related to weather and climate.

Most Danes know about the daily pollen counts from the DMI on radio and TV – useful for people suffering from hay fever and for other air tract allergists. In addition, in recent years an air pollution warning system has been launched, to inform people suffering from respiratory diseases. The National Environmental Research Institute is in charge of the daily air pollution forecasts prepared for heavily trafficked streets in Copenhagen.

The pollen season is longer

The columns show the starting dates of birch pollen – today three weeks earlier than 25 years ago. The DMI has observed significantly elevated pollen counts, and the pollen season – not only for birch, but also for alder and hazel – starts several weeks before it used to. This may be part of the explanation of the increasing number of recorded hay fever sufferers. The earlier pollen season is a more indirect effect of the warmer climate we have seen in Denmark especially in the 1990s and later.

(Data from Alix Rasmussen, the Danish Meteorological Institute)

Date of start of birch pollen season in the last 27 years. The red line is a linear regression through the data in the period 1977-2002 and illustrates that generally the season starts earlier.

According to Alix Rasmussen, the DMI, 2004.

In a warmer climate the nature of air pollution can change, for instance the photochemical air pollution, where nitrogen oxides and carbon hydrates from traffic forming i.a. ozone under the influence of solar light, can get worse. On the other hand, emissions of certain pollutants may be reduced when the consumption of carbon, oil and gas for heating becomes smaller. The overall result could be an improved air quality – at least locally.

In step with the changed climate conditions, special efforts may be required, for instance along the lines of the system in England, where meteorologists submit forecasts of weather-related effects on health to the hospitals.

Growing tourism – both good and bad
Not all future trends for climate and health are negative.

According to climate modelling, the climate in Denmark and the rest of Northern Europe will probably be more pleasant than in Southern Europe, where there is a risk of very hot summers. Tourists may change habits, and go to the north for their summer holiday. This will be good for the Danish economy on the one hand, but, on the other, it may also increase the risk of diseases which only occur very rarely today. More focus will also be required on environmental management, in order to cope with the increased pressure of tourists on the environment.

At global level the World Health Organisation WHO is very concerned about the health problems resulting from a changed climate. Elsewhere in the world the problems will be much larger than we expect them to be in Denmark.

Beside problems of heat stroke and infections, the UN Climate Panel and WHO expect many more cases of malaria every year. Malaria is already one of the World's most severe and widespread diseases, but may become even more so in both the tropics, the subtropics and less protected temperate zones.

Denmark is probably not among the countries that face immediate danger from malaria. But still, we should be aware that with a warmer and moister climate on our latitudes, the risk of diseases transmitted by mosquito and other insects increases.

In recent years we have seen the West Nile virus, WNV, spread by infected mosquitoes to large parts of the USA and Canada. Where it comes from, and what is the exact cause of its successful transmission, we do not know. Therefore nobody knows if it can be explained by unusually high temperatures in these parts of the world.

So far our cold winters have helped us control certain disease germs, but with rising winter temperatures the incidence of infectious diseases may increase. On the other hand, a lot of people catch infectious diseases, for instance a cold, during the winter, when the weather is cold and moist. All in all it is therefore difficult to predict the health implications of warmer winters.

The state serum institute SSI administers a scheme of surveillance and notification of a number of rare diseases in Denmark, under which doctors are obliged to report possible accumulation of inexplicable diseases to the SSI.

More detailed surveillance and recording of climate-related diseases in Denmark, within the framework of a contingency scheme or routine alerting of risks of a large number of weather-related diseases to the general public and to hospitals and casualty wards (like in England), should be considered.

Another relevant aspect is consideration of possible changes of livestock diseases.

WHO Europe is focusing on climate change and health

The WHO regional office for Europe has launched a project cCASHh (Climate Change and Adaptation Strategies for Human Health in Europe) to assess and enhance the adaptation possibilities to climaterelated effects on human health.
In 2003 WHO published a review of the human health consequences of storm surge in Europe and the implications for public health.

Example 5 Climate and health