Monday, May 9, 2011

Goa’s March Towards Meteorological Simplification

Goa’s March Towards Meteorological Simplification

By Dr Nandkumar M Kamat

So far we have discussed ecological simplification - how complex natural ecosystems get converted into managed ecosystems after losing their structure and functions.
A concrete example is the Goa University campus, which has lost most of its old wilderness, natural habitats, biodiversity of mammals, reptiles, birds, plants, and is fast marching towards a managed, artificially landscaped campus.
Meteorological simplification means having almost similar weather the year round. Goa’s weather pattern is marching towards meteorological simplification. What it means is that the difference between summer and winter is getting narrower. Only the monsoon rains make a difference, otherwise days are unusually warm for ten months of the year and nights are seldom cooler and tolerable. Winter reminds us of summer and summer heat has become extremely unbearable. This trend has been observed over the past two decades and matches very well with the global warming projections, Goa’s rapid urbanisation and loss of local natural heat sinks.
Unusually warm or ultra cool weather disrupts our biorhythm. It disturbs the routine and it is not easy to adapt to such changing temperature conditions. People love cold winters in tropical environments but cannot tolerate warm weather. Everywhere in Goa people are discussing the warm weather conditions. April 2010 has recorded some of the warmest nights on record for the past 100 years. This year there has been a record sale of air conditioners.
Combine warmer nights with high humidity and then the discomfort is total. High humidity suppresses sweating. Global warming is here, to be experienced in the small state of Goa with the mercury rising at night and breaking all past records for the month of April. People work during the day and expect cool, tolerable nights. It is difficult to predict what we would face in May, the warmest month.
Contrary to the view that the winter months are the coolest temperature records indicate that going by daily minimum and daily maximum temperatures July and August are the coolest months in Goa. A characteristic of Goa’s weather is the seasonal trend in the rise and fall of temperature. The minimum daily temperature is highest during May then it starts falling slowly, remaining almost constant during August to October. It decreases again from November and becomes lowest in January, the month with coolest nights. The trend is reversed after February. March, April and May are true summer months. But increase in maximum temperature during October to December shows that the old pattern is getting disrupted.
Why are summers getting warmer and why is there a general warming trend being witnessed? There are complex global factors and local anthropogenic factors. NASA had declared that the decade 2000-09 was the warmest decade since 1880. Warming effect is attributed to increase in carbon dioxide and other greenhouse gases which trap incoming heat near the surface of the Earth. But are these gases the only factors responsible?
Scientists have also identified three others key factors including changes in the sun’s irradiance, oscillations of sea surface temperature in the tropics, and changes in aerosol levels. These can also cause slight increases or decreases in the planet’s temperature. But these factors are not sufficient to explain global warming. There are two other complex weather systems - El Niño and La Niña.
These show how the oceans can affect global temperatures. El Niño describes abnormally warm and La Niña accounts for cool sea surface temperatures in the South Pacific that are caused by changing ocean currents. Global temperatures tend to decrease in the wake of La Niña, which occurs when upwelling cold water off the coast of Peru spreads westward in the equatorial Pacific Ocean. La Niña, which moderates the impact of greenhouse-gas driven warming, lingered during the early months of 2009 and gave way to the beginning of an El Niño phase in October that was expected to continue in 2010. The latest report from World meteorological organisation, which monitors both the systems, says, ‘During Jan-Feb 2010 conditions in the tropical Pacific continued to clearly reflect the presence of the El Niño event. Sea-surface temperatures remained more than 1 Degree Celsius warmer than normal across much of the central Equatorial Pacific, while large-scale atmospheric indicators of El Niño, such as increased cloudiness and convection in the central equatorial Pacific, were also firmly established.’
Indian meteorological department (IMD) does not predict the weather conditions for May, but going by the global trends it would be much warmer than before. Warmer temperature also means a daytime rise in dangerous solar ultra violet radiation that can affect eyes and the skin. It would be highest between 10 a.m. to 4 p.m. When meteorological simplification takes place, the impacts on nature, animals and humans is not easily discernible. The impacts of warmer May means drastic evaporation of water resources, drying of wells, stress on vegetation, rise in vector borne diseases, various types of viral diseases, gastrointestinal problems, skin diseases, proliferation of insect pests which favour warmer temperatures, rapid deterioration of food due to microbial contamination and proliferation and disruption of human activities.
Human workplace productivity is reduced with warmer temperatures. Warm temperatures also suppress the human immune system. Children are most vulnerable to a warmer summer and need protection against dehydration and diseases. Fish and shellfish would get easily contaminated because the bacteria in gut and on skin of the fish proliferate fast. Flowering and fruiting of plants gets affected. Pollinators get confused. Breeding cycles of insects, birds, reptiles, and amphibians gets affected. Certain weeds - aquatic and terrestrial - tend to proliferate at the cost of native species.
The disturbance regulation function of whole ecosystems evolves over millions of years. When climate change takes place abruptly on a smaller temporal scale how do these ecosystems adapt? A single silk cotton tree, Bombax ceiba, supports hundreds of species-from bacteria, fungi, lichens, birds to insects. The delayed flowering, early pod formation and rapid seed dispersal followed by luxuriant vegetative growth displayed by older silk cotton trees this year indicates a disturbing time ahead - squally weather, lightening storms, episodes of intense rainfall. From the normal five months the trees have compressed their flowering and fruiting cycle in four months. There could be a message in this phenomenon - a coming heat wave followed by violent, dusty storms and intense early rains.

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