June 2009

How do weather and climate impact health?

Message from Michel Jarraud, Secretary-General of WMO, on the occasion of
World Health Day 2009
(7 April)


Michel JarraudClimate variability and climate change have a huge impact on many health factors. In particular, extreme weather events can be an aggravating factor for many health issues. It is very important to address this issue at all stages and, first of all, the risk evaluation. Also to have preparedness measures and that goes through the issuance of early warnings, and but also after the disaster it is very often important to have weather information for the rescue operation. So it is very important that the health sector and the weather and climate sectors work together. Good decisions have to be based on good information, and it is very important that the health sector has available the best possible information, and this is where our two communities have to work very closely with each other.

It is effective to take prevention measures in case of disasters. You will get a cost:benefit ratio of the order of 1:7 and it will save a huge amount of lives. Over the last 50 years, thanks to proper early warning systems, we reduced by factor 10 the number of people who lost their lives because of extreme weather events and many of these lives were lost because of health issues.

Climate and health are linked in inextricable ways. With climate change we anticipate the number of these extreme events will increase and also the intensity, and when it comes to health there will probably be an increase in the occurrence of vector-borne diseases, malaria, dengue fever and many others. But, also, the quality of the water may be affected after floods, and that will have an impact on cholera. So you will have the vector-borne diseases, the water-borne diseases, climate warming will probably also mean a proliferation of toxic algae in the oceans. But when coming to food, in many countries the food production will be affected by the changes to the climate. It will have an impact on food security and, in turn, it will weaken populations in the Least Developed Countries and, as we know, a weaker population is more vulnerable to diseases. So if you keep in mind that about 90 per cent of all natural disasters are related to weather, climate and water, this proportion is likely to increase further with climate change. And it will have a dramatic impact on health. So it is really important that the two communities work together and that we properly integrate this information in decision-making. Good decision-making requires good information and this is particularly true in the Least Developed Countries, which are the most vulnerable but also the least able to cope with that, so it has to be a multidisciplinary approach.

Extreme events can put an extraordinary load on the health infrastructure. When extreme events strike like a storm surge, like a tropical cyclones, it has an impact not only on the infrastructure, but also sometimes on the health workers themselves, who may not be able to come to work, so it is very important to address this issue at all stages. First of all the risk mapping, to evaluate the risk at the risk preparation at the rescue phase. And let me give you some examples for each of these phases. On the risk mapping, it is very important to be able to locate hospitals in places which are not vulnerable to these extreme events. But also to have available proper building codes to enforce them, so that they will not be destroyed by earthquakes. I know that the earthquakes are not meteorological factors, but the weather, like during the earthquake in Pakistan, was an aggravating factor, because the buildings, including the hospitals, were destroyed before the winter came with the snow, with the very cold weather. So it is very important to factor in all of these elements at the planning phase. When it comes to prevention, to preparedness, early warning is the key. Good early warning systems properly integrated in disaster preparedness management are absolutely essential for saving lives and for a cost-effective response. Let me give you an example. In Botswana, proper use of seasonal forecasts—and I mean several months in advance—allows the government to plan for the next malaria epidemic and that is a very effective weapon to have a more cost-effective approach to that. In Europe, there was a big heat wave in 2003 and in France, for example, there was a heat health index which was developed in very close cooperation between the meteorological health service and the health community, and that will certainly help to save many more lives during a similar severe heat wave. But, when it comes to the post-disaster events, it is also very important to have proper information to coordinate our actions, and this is not something that which has to be improvised after the event. It has to be prepared in advance.

So I think all these actions together are very, very cost effective. It is estimated that if we invest something like $1, 1 euro, one of any currency in disaster prevention activities, the benefit to society is about seven to 10 times as big, and that includes the health sector, but it is important to focus on the developing and Least Developed Countries, because they are the ones who are the most vulnerable but also the least able to deal and to cope with these disasters.

If we keep in mind that about 90 per cent of all disasters over the last 50 years have been related to weather, climate, water, extreme events, what is noticeable is that there has been a significant increase in the number of such disasters: about 50 times more disasters than 50 years ago. But at  the same time we are losing about 10 times fewer lives than we were 50 years ago. So, the number of disasters increases but the numbers of lives lost is decreasing significantly. Why? Because of better early warning systems, better use of these early warning systems by all socio-economic sectors. And, in the first place, the health sector is making very, very effective use of these early warning systems. But, at the same time, the disasters are all different. An earthquake is not the same as a tropical cyclone, which is not the same as a flood. So what is important is to put in place a multi-hazard early warning system so that, irrespective of the disaster, we can use the same approach, taking into account the specificities. But, at the same time, it is very, very effective for disasters which happen very infrequently, like the tsunami, which may be once every 100 years in Indonesia, it is very important to have in place a multi-hazard warning system that can be tested and used for all kinds of disasters. So to do that, it is important that all the communities involved, the health sector, the meteorological sector, civil protection, all the other actors work together through national disaster management structure so that they work together to ensure the effectiveness of that.

WMO fact sheet

back to top


Condensed version/
version condensée
cover   cover
English   Français

Regular features
In the news
Recently issued
Upcoming events
Recent events
High-impact weather events

MeteoWorld archive
Archive MétéoMonde
WMO Bulletin


Contact: MeteoWorld Editor - WMO ©2008 Geneva, Switzerland