Mashida R Haider reveals how climate change stands to pose serious public health threats to large sections of the Bangladeshi population who are already at the margins of the health and nutrition programmes.

A news report from August 18, 2007, in the wake of the floods in Bangladesh, states:
   More than 53,000 people have contracted diarrhoea in Bangladesh, mostly caused by eating stale food and drinking impure water. A field hospital has been opened in the capital, Dhaka, to treat diarrhoea patients.
   ‘The overall diarrhoea situation is grim. Everyday there is a rush of patients,’ said Ayesha Khatoon, a senior official at the government’s health directorate. ‘We are trying to cope with it.’
   One doctor at the Dhaka-based International Centre for Diarrhoeal Diseases Research said the facility had received 1,100 patients on Tuesday; the highest single-day admissions in its history. ‘We suspect the flow will increase further,’ said Dr Azharul Islam Khan.
   The country’s interim government said it was doing everything possible to ensure that flood victims get food, clean water and access to healthcare.
   A report by the Intergovernmental Panel on Climate Change (IPCC), says:
   Average global temperatures will increase between 1.8°C and 5.8°C over the next century, and the sea level will rise between 9 and 88 centimeters with midrange estimates of 3°C global mean warming and 45 cm sea-level rise, respectively. Increased variability in the hydrologic cycle (i.e., more floods and droughts) is expected to accompany these global-warming trends. The rate of change in climate is faster now than in any period in the last thousand years. And while industrialised countries are most responsible for causing global warming, it is the low-income countries with little capacity to adapt that are the most vulnerable.
   With the juxtaposition of scientific facts by academics and theoreticians with cold, hard, reality, it is becoming increasingly difficult to shy away from the truth. Climate change is, indeed, not a myth.
   In October 1999, a cyclone in Orissa, India, caused 10,000 deaths. The total number of people affected was estimated at 10-15 million; in December 1999, floods in and around Caracas, Venezuela, killed approximately 30,000 people, many in shanty towns on exposed slopes. The hurricane Sidr, which hit Bangladesh’s southern coast on November 15, 2007, has already claimed more than three thousand lives, and the Red Crescent has expressed fears that the toll could cross the 10,000 mark.
   Research conducted, and reported on, from several sources indicate that climate change is likely to have several important impacts on Bangladesh. The most significant may be through sea-level rise. The IPCC Special Report on the Regional Impacts of Climate Change indicates that Bangladesh is ‘especially at risk’ from sea-level rise and its implications: coastal erosion and land loss, inundation and sea flooding, and increasing salinity of rivers.
   The bottomline is this: for poor countries like Bangladesh, climate change is not just posing a threat to livelihoods, food security, and ecology, it is increasingly a threat to the lives of millions of people. One of the most devastating ways that a changing climate will impact the lives of the poorest sections of society is through the threat to health that it will pose.
   In the short term, how regional governments react to the threat of climate change may have a greater impact than observed changes. India is already expressing concern about rapid melting of the Himalayan glaciers, which are expected to reduce by 80 per cent by 2035. In particular, the Gangotri Glacier, the source of the Ganges River, is retreating at an alarming rate. In response to this, the Indian Government may well decide to implement the Inter Linking River Project, which has been under consideration for many years. Projects like this and others would redirect the big rivers, including the Ganges, reducing water flow to Bangladesh and devastating the water supply for much of Bangladesh. In addition to these possible Indian projects, China also has revealed that it plans to dam the Brahmaputra River in Tibet in 2009 and divert water to the Yellow River and surrounding areas.
   Even without these projects, a receding water table caused a quarter of all shallow tubewells used for irrigation and drinking water in north and central Bangladesh to run dry in 2006. The reduction in river flow caused if these projects are implemented could greatly exacerbate an already serious water problem.
   In its Third Assessment Report, the IPCC concludes that: ‘Overall, climate change is projected to increase threats to human health, particularly in lower income populations, predominantly within tropical/subtropical countries.’
   That summary goes on to state: ‘ Climate change can affect human health directly (e.g., impacts of thermal stress, death/injury in floods and storms) and indirectly through changes in the ranges of disease vectors (e.g. mosquitoes), water-borne pathogens, water quality, air quality, and food availability and quality. The actual health impacts will be strongly influenced by local environmental conditions and socio-economic circumstances, and by the range of social, institutional, technological, and behavioral adaptations taken to reduce the full range of threats to health.’
   Broadly, a change in climatic conditions can have three kinds of health impacts:
   Those that are relatively direct, usually caused by weather extremes; the health consequences of various processes of environmental change and ecological disruption that occur in response to climate change; the diverse health consequences – traumatic, infectious, nutritional, psychological and other – that occur in demoralised and displaced populations in the wake of climate-induced economic dislocation, environmental decline, and conflict situations.
   In addition to its effect on sea level and government policy, climate change also is likely to have important effects on the prevalence of infectious diseases in Bangladesh.
   Currently, malaria is not considered a major challenge in the national health sector programme because its prevalence is restricted to certain geographic zones principally in the Chittagong Hill Tracts and similar areas. Even so, over 10 million people are at risk of malaria. The Anopheles mosquitoes tend to prefer a temperature range from 24 to 27 degrees Celsius. If the overall temperature were to rise as predicted, their habitat may be reduced, leading to a possible decrease in malaria with climate change. But that’s where the good done by climate change ends. Dengue is an increasingly a commonplace virus in Bangladesh, and most government emphasis has been on improving treatment, mainly through rehydration. It is reasonable to predict, say experts, that global warming would produce more rapid replication of the dengue virus.
   Visceral leishmaniasis (VL), also known as kalaazar in this region, occurs in approximately 14 northern districts (of 64 nationwide) and is moving south. It is unclear how VL might respond to higher temperatures, but reported cases seem to cluster near flood control embankments, and building more embankments seems a likely response to sea-level rise. This in turn is expected to favour VL vectors and may result in increasing cases of visceral leishmaniasis in Bangladesh.
   Cholera and other diarrhoeal diseases are an obvious risk in Bangladesh. There is an established link between cholera outbreaks and blooms of blue-green algae. These blooms are in turn associated with rising concentrations of phytoplankton that follow El Nino, the well known warm phase of the large warm/cold oscillation in the water and atmosphere of the Pacific region that has been described as the world’s largest and most powerful weather engine. How climate change might affect El Nino is unknown, but it appears to be a delicate system very sensitive to background inputs meaning climate change could well have an effect.
   Marked short-term fluctuations in weather can cause acute adverse health effects. Extremes of both heat and cold can cause potentially fatal illnesses, e.g. heat stress or hypothermia, as well as increasing death rates from heart and respiratory diseases. In cities, stagnant weather conditions can trap both warm air and air pollutants - leading to smog episodes with significant health impacts.
   These effects can be significant. Abnormally high temperatures in Europe in the summer of 2003 were associated with at least 27,000 more deaths than the equivalent period in previous years. Other weather extremes, such as heavy rains, floods, and hurricanes, also have severe impacts on health.
   Because of the disasters brought about by climate change, food security has become a major issue. Food security is achieved ‘when all people at all times have physical and economic access to sufficient, safe and nutritious food for a healthy and active life’. The components of food security are: the availability of food, or the amount of food that actually exists (local production and other sources); people’s physical, economic and social access to food (the capacity to produce/buy/acquire food), and the stability of this access over time; the quality or nutritional adequacy of that food; and people’s ability to utilise this food, including the patterns of control over who eats what and the physical ability to absorb nutrients (affected by health status factors such as intestinal parasites. These are determined by physical, economic, political and other conditions within communities, and are undermined by shocks such as natural disasters and conflict.
   Undernourishment is also an indicator sometimes used to assess food security levels. Based on national food production figures, it is a measure of food availability. Malnutrition is the condition caused by deficiencies or imbalances in energy, protein and/or other nutrients. Signs include wasting (thinness), stunting (shortness), or being underweight (low weight for age due to wasting/stunting).
   Protein-energy deficiency is a leading cause of child death in developing countries. Deficiencies in micro-nutrients (vitamins and minerals) can also affect mental and physical health. For example iron deficiency anaemia remains a major health problem and can negatively impact on health, life-expectancy, work productivity and economies.
   Epidemiology, therefore, has a major role to play. It has to continue documenting the associations between climate change and health outcomes more specifically both in terms of exposures and outcomes. Research needs to be conducted on future scenarios based on advanced modelling, applying projections at local or regional level downscaling the current projections and dynamics based on several climate models; relating climate and health with a broad range of socioeconomic environments; carry out validation studies of the projected future scenarios based on empirical data; and obviously, perform classical longitudinal studies on present and past patterns on a broad range of health effects due to climate, particularly in subtropical regions.
   ‘Early warning systems’ such as the weather-watch warning system based on climate-based models to predict the occurrence of heatwaves have to be set up. This system has already allowed taking preventive actions including health services plans that have reduced notably the impact on health. Intervention plans may also be undertaken after early predictions of events such as hurricanes or flooding particularly in developing countries (but also in the poor areas of the developed world).
   Vector-borne disease control programmes have to be implemented, based on interventions developed using risk-assessment and cost-benefit technologies. These procedures should incorporate existing knowledge on, for example, resistance of mosquitoes to insecticides or long-term effects of low doses of pesticides, as well as environmental actions, and therapeutic plans and other health interventions strategies of proven efficiency. Also, research on primary prevention of vector-borne diseases through control of the ecology of mosquitoes or vaccination has to be boosted.
   The health impacts that climate change will have on Bangladesh is almost beyond the realm of the quantifiable. It has the potential to offset and perhaps outstrip much of the good that targeted programmes to improve nutrition and public health have wrought over the past decades. And predictably, it is the poorest who will suffer the worst excesses of the health impacts. Chronic malnutrition caused by shrinking foodgrain absorption—which is turn will be caused by more frequent flooding—will make those at the margins of Bangladesh’s healthcare and nutrition initiatives even more vulnerable. And that, is just the tip of the iceberg.