• Saturday, September 20, 2014

Climate Change

Impacts of El Niño in Bangladesh

Dr. Md. Rashed Chowdhury

Currently there is an 80% chance of an El Niño [(e.g., positive or warming sea surface temperature in the eastern Pacific (SST-EP)] developing by July-August-September, or it may develop by October-November-December this year. Whatever the timeframe is, this El Niño could have a huge global impact and may be even more severe than previous occurrences (the figure illustrates a hypothetical comparison of the impact of El Niño in the past and today).
While the El Niño forecasts published in April lean towards a strong El Niño in 2014 (e.g., like the 1997 event), the forecasts in May tended to show a weaker event than that in1997. I also anticipate a weaker than 1997 event this year because of some favourable ocean conditions [e.g., currently the negative (cold SST-EP) or neutral phase of Pacific Decadal Oscillation (PDO)] that may prevent this year's El Niño from becoming as strong as the 1997 event [e.g., PDO was in positive phase (warm SST-EP) during 1997 El Niño]. This is indeed good news for Bangladesh! However, this year's El Niño may still cause lower than normal rainfall, warmer than normal temperature, drier than normal climate, and higher than normal cyclonic activities for the next six to eight months in Bangladesh.
Some of the most important sectors where the impacts of 2014 El Niño could be visible include the following.
Agriculture: El Niño impacts on agriculture in Bangladesh can be strong, as demonstrated in past El Niño events, and are linked to water shortages, soil degradation, and disruption in planting seasons. Low rainfall is directly associated with reduced rice yields.  This would significantly affect food security. Droughts during El Niño may be interrupted by devastating cyclones, as occurred on November 29-30, 1997and April 29-30, 1991 that killed 150,000 people. Drought conditions can also lead to devastating forest and grassland fires that threaten biodiversity, wildlife, and livelihoods.
Water and Energy: In Bangladesh, water supply and its availability will be impacted by drought conditions from El Niño. For water systems that do not have a reliable surface water source, reduced rainfall could create shortages in the water supply. Water users, either districts or individuals that rely on ground water, may see a degradation in water quality as lack of groundwater recharge from reduced rainfall can lead to increased saltwater intrusion. Already water-stressed areas may become more stressed with reduced rainfall. These impacts will also be felt in the energy sector as hydropower production may decline due to water availability in reservoirs and rivers. If hot conditions persist, energy use for cooling can put additional demands on energy grids. However, water and power problems are nothing new in Bangladesh; even without El Niño Bangladesh has already suffered the severe effects of water and power shortages. The El Niño of 2014 is likely to further aggravate this problem.
Urban Areas: As rural, especially agricultural areas, are impacted by El Niño conditions, cities may experience high rates of migration that can put a strain on provision of basic and social services. Additionally, reduced agricultural productivity will threaten cities with food security challenges, even more pronounced among already vulnerable groups like the urban poor.
    Health Sector: There is evidence that El Niño is associated with a heightened risk of certain vector-borne diseases in Bangladesh. This is particularly true for malaria, but associations are also suggested with respect to epidemics of other mosquito-borne and rodent-borne diseases that can be triggered by El Niño weather conditions. Some recent studies have found correlations between cholera incidence in Bangladesh and sea surface temperatures in the Bay of Bengal, which are also affected by El Niño.


Probability of new civil conflicts: Drought is widely believed to relate to conflict because it may lead to local scarcity and increased resource competition; freshwater is the resource most vital to human existence. The Sudanese government, NGO officials, and some scholars have used the drought in the mid-1980s as a partial explanation for the conflict and killings in Darfur (Ban-ki Moon, 2007. "A Climate Culprit In Darfur," Washington Post, June 16: A15). Despite some criticism, the emerging research on the effects of water scarcity on armed conflict has produced an important insight that "a negative change in water accessibility appears to be harder to adapt to and potentially more important for conflict." Similarly, civil conflicts arising throughout the tropics doubles during warm or dry or drought (El Niño) years relative to normal or cold or flood (La Ninã) years (note that La Ninã is the opposite of El Niño).  While historians have argued that El Niño (and La Ninã) may have driven global patterns of civil conflict in the distant past, a new study (Nature 476, 25 Aug 2011) directly associated planetary-scale climate changes with global patterns of civil conflict by examining El Niño (and La Ninã) and concluded that the new civil conflicts arising throughout the tropics doubles during an El Niño year relative to a La Ninã year or a normal year. This result, which indicated that El Niño (and La Ninã) may have had a role in 21% of all civil conflicts since 1950, is the first demonstration that the stability of modern societies is strongly related to the global climate. Bangladesh also had serious civil conflicts and political unrest during the El Niño years in 1970-72, 1982-83, 1991, and 2013-14.
This year's El Ninõ has generated a global momentum for early preparation. Many national and international research and applications climate centers are constantly monitoring this event and regularly updating early warnings for vulnerable communities across Asia and the Pacific. I believe, as one of the most resilient nations in disaster management, the climate experts and concerned applications agencies in Bangladesh are seriously monitoring this on-going El Niño event. Finally, as 2014 develops into an El Ninõ year, this could exacerbate the possibility for new civil conflicts to erupt. The government and all political parties should give serious consideration to this sensitive climate issue during any political activities.

The writer is the Principal Scientist (Graduate Faculty) of the 'Pacific ENSO Applications Climate Center', University of Hawaii Manoa, USA (Email: rashed.uh@gmail.com).

Published: 12:00 am Thursday, June 05, 2014

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