30 August 2002
Floods Affected over 17 Million People Worldwide
(Reissued as received.)
GENEVA, 29 AUGUST (WMO) - Floods in more than 80 countries have caused hardship for more than 17 million people world-wide since the beginning of 2002, according to the World Meteorological Organization (WMO). Almost 3.000 people have lost their lives while property damage is amounting to over thirty billion US dollars. The total area affected by the floods is over 8 million square kilometres, almost the size of the United States of America.
At any time throughout the world a river somewhere is in flood and its waters are threatening communities, their property and even their lives. Few of these events are reported in the headlines due to their local impact. However, the floods in Central Europe and China have drawn international attention. At the other end of this extreme water overload are droughts that have been and are still occurring around the world at the same time.
Droughts and floods both have major impacts on the socio-economic well being of countries. In some cases, countries experience both extremes simultaneously as is currently occurring in India and Niger. Serious droughts are occurring in the SADC countries of southern and central Africa, which is resulting in starvation and global outcry for food aid. In North America, over 37% of the United States are suffering from a severe drought with the longest-lived drought in the southeastern states.
A delayed monsoon in India has resulted in unseasonably hot and dry conditions throughout northern and western parts of the country; its impact is a 10 million-ton drop in India's rice crop. Australia is stricken by severe rainfall deficiencies across eastern portions of the country, resulting in serious crop loss and a need for drought aid packages to farmers.
Causes of European floods
Since the middle of June, much of Europe received between 200 and 500 mm of rain. Recently, within a few days, between 100 and 400 mm fell over much of Europe from England southeastward to the Black Sea. The result was record floods on a number of rivers, most notably the tributaries and then the main stream of the Elbe and the Danube. The Danube exceeded the previous highest recorded level by 3 cm in Budapest, by 22 cm in Komaron and by 30 cm in Esztergom. The Vltava and the Elbe both flooded to levels estimated to be such as could be expected only every 250 to 500 years.
Efforts to protect the cities and towns from floods have been very successful in many instances, but sadly ineffective in others. In both cases the costs have been very high, mounting to millions of dollars for the protective measures alone and billions of dollars where, despite the best efforts, casualties occurred. Most regrettable is the need to register the deaths of over one hundred people.
Causes of Chinese floods
In China, as in Europe, the months of June and July were very wet and in fact the Xiangjiang, Xijiang and Yangtze Rivers flooded large tracts of land in the southern part of China. The most recent event, the flooding of Lake Dongting was caused by extremely heavy rain falling on already saturated land. The intensity of the rain in some locations has even been assigned a return period of 1000 years. The result has been another major flood descending the Yangtze River and flowing into Lake Dongting.
Causes of droughts
Droughts are simply caused by a prolonged deficit from the normal amount (amount expected based on history) of precipitation. Droughts can be short lived, weeks or months, or long lived, seasons or years. But the cause is the same, too little precipitation. Drought conditions can be enhanced by over use of water resources, poor ground cover, incorrect crops and poor land usage to name only a few.
Causes of disasters
There is no way of saying whether these floods were or were not associated with climate change; we will only be able to say something when our grandchildren look back over 50 or 100 years to put these events in the overall context of the 20th and 21st centuries. What we can say, however, is that there is already evidence of increasing precipitation in Northern Europe and the Intergovernmental Panel on Climate Change (IPCC), established by WMO and UNEP in 1983, is confident in predicting increased flooding in the future.
Certainly, upstream changes in land use and river "improvements", which were made in the past for good economic and social reasons, will have caused some increase in the flood peak and speeded its arrival downstream. But these effects are likely to have been negligible in comparison with the following simple facts:
the upstream river basins were already saturated from earlier rains;
there were a series of very heavy storms that deposited large, in some cases record, amounts of rainfall;
large volumes of water flowed downstream and, having nowhere else to go, occupied or tried to occupy their natural flood plains and, in the case of the Yantze, its natural overflow lake;
hundreds of years of development have led to the occupation of these banks and flood plains by housing, by industrial and commercial properties and by agricultural activities,because they represent a valuable resource of flat land and alluvial soil.
WMO's national counterparts, the National Hydrological Services of the countries concerned are analyzing the events to provide their governments with advice as to how to guard against future natural disasters of this nature.
The investment in the flood plains is so large, and of such great historical importance, that there can be no question of relocating it elsewhere. Yet, such floods are natural phenomena that will certainly occur again, whether in one year, or ten years, or not for one hundred years - but when they do these areas will once again be under threat. The management of floods must be integrated with the management of the flood plains and upstream catchment areas from which the waters flow.
Decisions will have to be taken as to whether to try to store or divert the floodwaters upstream 1. at great expense and with major environmental impact 2. or raise the levees protecting the areas concerned -- but to what level and at what cost? 3. or to rely on forecasting and emergency response measures. These decisions cannot be taken hastily because they must take account of the full impact of each measure, including the need to manage river flows in times of drought as well as flood. The link between floods and droughts is important. They are the two extremes of the same constantly varying environment in which we live and with which we must learn to live in harmony.
We cannot stop droughts from occurring but we can diminish their impact on communities by understanding the normal precipitation and its seasonal and annual variability; through improved land usage consistent with the precipitation in an area; through improved water management and ensuring local communities, cities and states are developing and implementing contingency planning for precipitation deficit and drought situations.
The role of National Meteorological and Hydrological Services
During the recent floods, thanks to WMO's global observing and forecasting networks, the National Meteorological Services forecast the rainfall with considerable accuracy and the National Hydrological Services were able to provide the defence and rescue teams with good advance warning of the rise and fall of the waters. These national agencies, working under the auspices of WMO, have long experience of international co-operation; upstream and downstream countries coordinated their efforts to ensure the maximum of advance notice was given. Nonetheless, forecasts can still be improved by giving national agencies increased importance in terms of resources enabling them to upgrade their forecasting systems and improve their services.
For more information, please contact:
At the WSSD In Johannesburg
Ms. Carine Richard Van Maele
Chief, Information and Public Affairs
World Meteorological Organization
Sandton Conference Center
Phone: +27 (0) 82 858 33 42
Fax: +27 11 234 08 83
Phone +41(0) 22 730 85 32
AT WMO Headquarters
Ms. Mo Loagarde
World Meterological Organization
7 bis, Av. De la Paix
CH-1211 GENEVA 2
Phone: +41 (0) 22 730 85 32
Fax: +41 (0) 22 730 80 27
* *** *