Are the floods due to climate change?

All indications are there that the frequencies of flood events in Bangladesh and in other flood prone regions of our world will increase considerably in the next few years with the possible rise of global sea water and melting of polar and mountain ices. A staggering number of people, billions of them, mostly poor, will be gravely affected from these possibly catastrophic events. Should the world just ignore this frightening possibility? What can be done to minimize the coming distresses of innocent people stranded in flood prone places?

What is needed is a global coordination and cooperation among nations, rich and poor, to develop and execute a sustained plan for a grim future to come. Perhaps, international funded flood preparedness is an option. Perhaps, more constructions of barriers like Holland to push back rising water need to be widespread, but I have serious doubt on the effectiveness of such barriers in rapidly rising sea water. Perhaps, serious discussions should be taking place regarding migration of people, hundreds and millions of them to various geographically stable places of our world to give them a better chance of survival in life.


Are the floods due to climate change?

By Saleemul Huq

As Bangladesh faces another major flood affecting millions of people and large parts of the country the question is being asked whether these floods are caused by human induced climate change? While it may not be possible to attribute this particular flood event to climate change, nevertheless the enhanced frequency of such events can be predicted in future due to changes in the global climate system caused by emissions of greenhouse gases by human activities.

That the global climate is warming due to the accumulation of greenhouse gases (such as carbon dioxide and methane) in the atmosphere is a well-documented fact (the levels have almost doubled from pre-industrial times). The Intergovernmental Panel on Climate Change (IPCC) is the body consisting of several hundred of the world's leading scientists set up by the United Nations to examine the evidence regarding climate change. In its last (third) report published in 2001 it unequivocally stated that human induced climate change is a fact and is undoubtedly happening. These conclusions are based on a combination of many observations from all parts of the globe (from the polar regions to the tropics) of unprecedented changes in climatic patterns along with global circulation models (GCMs), which also predict quite conclusively that the atmosphere will definitely get warmer over the next five to ten decades. They also predict with a very high degree of confidence that such an atmospheric warming will cause sea levels to rise by several meters over the next five to seven hundred years.

However, while the predictions have a high degree of confidence over the long term (i.e. hundred years or more) the degree of confidence over the short (five to ten yeas) and medium (ten to twenty years) term is less. It is also relatively difficult to model the changes in variability of the climate, which may be caused by global atmospheric warming. As floods and cyclones represent the extremes of natural climatic variations we are naturally interested to know what is likely to happen to such extreme events in a warmer world? Although the climate modellers are not able to make accurate predictions about such extreme events in the short term they are able to say that the likelihood of extreme events will indeed become more frequent (if not necessarily more severe). Thus, one in twenty-year event (such as the current floods) is possibly likely to become one in five-year event. This is already demonstrated by the fact that the last flood of similar magnitude occurred not twenty years ago (as we might have expected without any global warming) but only six years ago in 1998. While this does not prove conclusively that this flood is due to global warming -- it does indicate that the frequency of such floods in future will be much greater than in the past.

The consequence of this knowledge is that we need to be better prepared for such floods in future. In the case of the present floods we got the warning about rising waters days ahead and were able to take some (although, admittedly quite inadequate) measures. In future there will no longer be any excuse for saying that we did not know there would be floods. We must prepare every year as if we will be flooded. This does not necessarily mean that floods of such a magnitude will occur every year but the prudent course to follow is to prepare for the worst-case scenario.

This requires a whole set of changes in our attitudes and actions ranging from improved meteorological and hydrological information for prediction and warning; making flood warning more accurate with respect to which localities will be affected, by how much and when; improving evacuation procedures, providing safe shelters on raised grounds, building all future roads at higher levels with more sluice gates to allow flow of flood water; building protective embankments for high capital value infrastructure or densely populated areas only (it will be impossible to protect everyone and everywhere); stockpile water purification tablets, medicines and dry food; prepare health centers for diarrheal patients and snake bites; prepare seed beds for seedlings after the floods recede; as well as a hundred other actions to be taken from national policy makers to sectoral ministries, local administrations, political parties, NGOs, colleges, schools down to individual citizens. We need to be ready for such disasters every year from now on as if putting the country on a war footing. If the floods are not as bad then we will not have lost much, but if they are bad then we will be better prepared and better preparation will reduce the adverse impacts considerably.

Although it may seem from the above analysis that the future for Bangladesh looks very bleak indeed with respect to future floods, it does not necessarily have to be that bad. There are at least a couple of important (albeit small) silver linings behind the dark and rain-laden clouds. Firstly, with better information, preparation, warning, action and rehabilitation we can reduce the adverse impacts of severe events such as this year's floods (this was well demonstrated during the floods of 1998 and hopefully will be demonstrated again in 2004). Our national and local administration, NGOs, Red Cross and private citizens have risen to the challenge in the past and can do so again in the future.

The second aspect is the fact that floods due to climate change (even if not hundred percent attributable to climate change) are fundamentally different from "normal" floods. Even though scientists cannot (yet) attribute a percentage to how much the floods are due to climate change they are reasonably sure that such a percentage is a positive number greater than zero. Whether it is 0.1, 1.0 or 10 percent is not possible to attribute at the moment (but it will be possible within a few years) it is definitely not zero anymore. This fact opens up an entirely new level of calculation for the floods. Whereas in the past they could be attributed entirely to acts of God (or nature), in future they will also be (if only partially) attributable to acts of man as well. It is also well known which countries are primarily responsible for the problem of global warming -- namely the rich countries of the world.

Thus, in future we can legitimately claim assistance from the rich countries of the world to face climatic disasters (such as floods) not just through appeals to their charity but as compensation (appealing to their moral responsibility, if not their legal liability). However, in order to obtain financial flows at the level required, Bangladesh must learn to take the problem of climate change much more seriously than it has done so far and must learn to participate in the international negotiations in a much more strategic and planned manner.

Saleemul Huq is Director, Climate Change Programme, International Institute for Environment and Development, UK and Chairman, Bangladesh Centre for Advanced Studies.