Strongest El Nino in history could worsen flooding in Nigeria
• How climate change threatens health, by studies • Cholera, meningitis, malaria, pneumonia implicated
SCIENTISTS have raised alarm of possibly the approach of the strongest El Nino event ever, which is expected to worsen adverse weather events like flooding, mudslides, bush-fires, severe Harmattan.
Forecasters with the United States (US) National Oceanic and Atmospheric Administration (NOAA) have said that the El Niño weather pattern developing in the Pacific Ocean could eventually rank among the strongest on record.
According to a report published in Nature, a strong El Niño — signalled by the periodic warming of ocean-surface temperatures in the equatorial Pacific — can lead to heavy rain in parts of Africa and North America and drier-than-normal conditions in Australia, Indonesia and parts of India.
NOAA says that there is an 85 per cent chance that the current El Niño will last through the first few months of next year, with its strength peaking in November or December.
Nature explains why this El Niño is unusual, and how it might affect weather around the world.
The weather pattern is the product of a complex dance between sea-surface temperatures and atmospheric conditions.
Normally, trade winds from the east drive cold water from the depths of the eastern Pacific Ocean to the surface. But sometimes those winds weaken, causing the ocean surface to warm and heat the air above it. That warm air rises, and moves north and south from the equator — altering the high-altitude air currents along which storms tend to travel.
Nigeria penultimate Thursday warned tens of thousands of people living along one of its main rivers to expect massive flooding due to heavy rainfall between August and November and as neighbouring Cameroon announced plans to release water from a dam.
The National Emergency Management Agency (NEMA) said it had been informed that the Lagdo dam in northern Cameroon would be emptying water into the River Benue until November to relieve an excessive build-up.
The opening of the dam as well as heavy rain in 2012 led to huge flooding along the river, the main waterway in eastern and central Nigeria.
How do scientists forecast an El Niño?
Forecasters in the United States, Japan and Australia monitor sea-surface temperatures in the Pacific, paying particular attention to a region called Niño 3.4 in the eastern equatorial Pacific. They also track water temperatures below the ocean surface and the air pressure above, then feed this information into forecast models.
If ocean-surface temperatures in the Niño-3.4 region are between 0.5 to 1 °C above average during a three-month window, NOAA declares a weak El Niño. Forecasters label an El Niño as strong if it exceeds the average by 1.5 °C. NOAA projects that the current event could produce temperatures that are 2 °C higher than average, or more.
For comparison, the strongest El Niño on record occurred in 1997–98 and produced temperatures 2.3 °C above average.
What makes this El Niño different?
Two things. It started unusually early — in March instead of June. This could be because warm waters left over from last year’s weak El Niño gave it a head start, says Anthony Barnston, chief forecaster at the International Research Institute for Climate and Society at Columbia University in Palisades, New York.
And this would be the second El Niño year in a row, following the weak El Niño that developed late last year, Barnston adds. A similar El Niño double-header happened between 1986 and 1988, but forecasters predict that the current El Niño will become stronger than either of those two events.
What is the effect of climate change on the health of Nigerians?
Researchers from the Department of Geography & Environmental Management, University of Ilorin, in a study published in Environment and Natural Resources Research; Vol. 3, No. 1; 2013 found: “The result shows that there is a very strong positive correlation between minimum temperature and typhoid (0.844), maximum temperature and malaria (0,794), typhoid (0.793), between sunshine and typhoid (0.667), malaria (0.630). The other variables are weakly correlated with the diseases.
“The regression analysis reveals that 49 per cent, 88 per cent and 79 per cent of the variance in asthma, typhoid and malaria can be respectively explained by the climatic parameters under study to a certain extent. This implies that there may be some other factors that are responsible for the selected diseases in the area. Such factors may include biological (genotype, micro-organisms, and allergies), unhygienic environment and economic (poor living conditions).”
The study is titled “Impact of Climate Variability on Human Health in Ilorin, Nigeria.”
The authors recommended among other things: that weather report should be broadcasted to people through the media in order for them to understand variation in the climate and how to adapt and mitigate the effect of the changes. Furthermore, people should be enlightened on the effects of anthropogenic activities in the atmosphere and how to reduce these effects for sustainable development.
Nigerian researchers in another study published in Asian Journal of Business and Management Sciences concluded: “Climate change is speeded up by increase in anthropogenic carbondioxide (Co2) and other green house gases plus the depletion of ozone layer which allows the penetration of ultra violet rays. Climate change or global warming cause sea level to rise and the consequences result in flooding from heavy rainfalls induced by precipitation, also from climate change. The deleterious effect of increase in ambient temperature is shown in this study to significantly influence increase in morbidity rate in Nigeria.
“Four diseases; cholera, meningitis, malaria and pneumonia were implicated as the major health risks exacerbated by climate change.”
Meanwhile, the World Health Organisation’s (WHO) Fact Sheet on “Climate change and health” said climate change affects the social and environmental determinants of health – clean air, safe drinking water, sufficient food and secure shelter.
The document noted: “Between 2030 and 2050, climate change is expected to cause approximately 250 000 additional deaths per year, from malnutrition, malaria, diarrhoea and heat stress.
“The direct damage costs to health (that is excluding costs in health-determining sectors such as agriculture and water and sanitation), is estimated to be between US$ 2-4 billion/year by 2030.
“Areas with weak health infrastructure – mostly in developing countries – will be the least able to cope without assistance to prepare and respond.
“Reducing emissions of greenhouse gases through better transport, food and energy-use choices can result in improved health, particularly through reduced air pollution.”
Patterns of infection
Climatic conditions strongly affect water-borne diseases and diseases transmitted through insects, snails or other cold blooded animals.
Changes in climate are likely to lengthen the transmission seasons of important vector-borne diseases and to alter their geographic range. For example, climate change is projected to widen significantly the area of China where the snail-borne disease schistosomiasis occurs.
Malaria is strongly influenced by climate. Transmitted by Anopheles mosquitoes, malaria kills almost 800 000 people every year – mainly African children under five years old. The Aedes mosquito vector of dengue is also highly sensitive to climate conditions. Studies suggest that climate change could expose an additional two billion people to dengue transmission by the 2080s6.
Measuring the health effects
Measuring the health effects from climate change can only be very approximate. Nevertheless, a WHO assessment, taking into account only a subset of the possible health impacts, and assuming continued economic growth and health progress, concluded that climate change is expected to cause approximately 250 000 additional deaths per year between 2030 and 2050; 38 000 due to heat exposure in elderly people, 48 000 due to diarrhoea, 60 000 due to malaria, and 95 000 due to childhood undernutrition7.
Meanwhile researchers at Columbia University’s National Center for Disaster Preparedness (NCDP) and the University of Washington, United States, have published a new study focused on the public health implications of climate change.
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