By Naba Bhattacharjee
Bright sunshine, day temperature hovering around thirty degree centigrade, clear blue sky punctuated by gathering dark clouds which dissipate in minutes failing to precipitate as rain. It is not the weather report of any town in the north or west of the country, but our own Shillong, where due to its latitude and high elevation has a sub-tropical climate with normal characteristics of mild summers and chilly to cold winters.. The entire Khasi and Jaintia hills, particularly Shillong plateau is on the threshold of a noticeable deviation in climatic conditions, perceptible since 2005 -2006. Although the phenomenon of “climate change” is yet to be conclusively established, “variation in climate” is being actually experienced all over the globe. In Shillong plateau, people are sweating out the unprecedented heat and unusual reduction in rainfall which is presently going through a deficit ranging from 40 to 65 percent, corresponding to normal precipitation during months of June and July even a decade earlier.
This situation has undergone rapid changes in course of the last decade with apparent rising temperature coupled with reduction in rainfall in and around Shillong plateau. The highest temperature on a particular day in Shillong during 2011 was recorded as 27.5 degrees Celsius while it jumped to 28.9 in 2012 while corresponding highest rainfall for a particular day was 198.9 mm and 134 mm respectively for the two years. (Data IMD – Annual Climate Summary). Climate of a place is the average weather that is familiar over a period of time. The factors that determine the climate at a location are the rainfall, sunshine, wind, humidity, and temperature – all of which have been exhibiting a significant erratic variation for the worse. Such variations are dynamic, following a natural cycle and hence not easily noticeable. However, in our case the striking feature is that the transformation has been manifesting itself within a few years. Scientists are finding evidence of such changes from tree rings, pollen samples, ice cores, and sea sediments. Over the last 100 years the change has been rapid to which certain plant and animal species have found hard to adapt. However the alteration in this region, particularly the declining rainfall pattern, has been marked since last few years. Hence strategy of adaptation and adoption to climate change or variation has to be accorded priority. Adaptation concerns how farmers for e.g. adjust to changing temperature, precipitation, and carbon dioxide levels while adoption concerns how quickly farmers take advantage of new technologies to meet the challenge.
Human induced activities are primarily responsible for the speed at which this change has occurred. It has acquired the potential to culminate into serious ecological aftermath. The causal factors are mainly the quantum leap in extraction and use of fossil fuels, destruction of forest and bio-diversity, increase in population, unregulated mining and quarrying, rising vehicle population et al. The atmosphere surrounding us has greenhouse gases of which carbon dioxide is the most harmful, released in large volumes due to above activities together with methane, nitrous oxide etc. The enhanced greenhouse effect is more commonly referred to as triggering global warming. Further, ozone layer has determined the temperature structure and safeguarded life on the planet by absorbing the harmful ultraviolet rays of the sun. But in the past half-century, humans have upset the delicate balance of nature and in the process destroying this life-protecting layer. The outcome is the increasingly common sight of gathering dark clouds in the Shillong skyline; being mostly incapable of precipitating or at most falling as light drizzle. The moisture bearing clouds evaporate due to high atmospheric temperature.
Emergence of a “Micro Climatic” zone is ostensibly in progression within Shillong plateau, reflected in the prevailing scenario of high temperature and low rainfall. Lack of precipitation due to increased atmospheric temperature and dissipation of rain or moisture bearing clouds is a common sight these days. The surrounding locales of Shillong are however experiencing near normal rainfall which further lend credence to a Shillong centric climatic variation, receiving few light drizzle at night when there is a fall in atmospheric temperature and a modicum of precipitation is possible. This perceptible variation will adversely affect the population of the capital directly because of alterations in temperature and rainfall. A warmer climate within Shillong plateau is having direct impact on rainfall patterns and increase in the level of evaporation of surface water with threat of rise in the number of cyclones and hurricanes. This, in turn, will affect water resources, forests, and other natural ecological systems, power generation, infrastructure, and human health.
Change in rainfall pattern is one of the most certain and imminent predictions of climate variation, closely followed by disruption of safe drinking water sources. Ecosystems which sustain the earth’s entire storehouse of species and genetic diversity are very sensitive to changes in climate. If the rate of climate change continues to accelerate, then the extinction of some plants and animals, endemic to our region is certain. The adverse effects have the potential to be catastrophic for humankind. There is still a great deal that we do not understand about our climate, and about how our activities will change it. But one thing is clear – the process of reversing the human induced activities as highlighted above have to start in earnest or else it will probably be too late!