de Silva Wijeyeratne, G. (2007). Switch Off Your Lights. Montage. April 15-May 15. Pages 8-9. Volume 1, Issue 4.
Global warming and Sri Lankan wildlife.
Climate change is nothing new. Ice ages have come and gone. Sea levels have risen and fallen. Sand now blows across deserts where once tropical rainforests existed. What is different with the current debate on climate changes is that it is happening very fast, within the span of our lifetimes. We may see what has being described as the single biggest challenge facing humanity. The fact the earth is getting warmer is largely accepted. However it is still under debate by scientists as to whether it is due to the action of humankind. The alternative theory is that it is a part of the many seemingly random variations in the earth’s climate. Even if our actions are not a key contributor to global warming, it still makes sense for us to take mitigative steps on the assumption it is. By doing so at the very least we minimize our contribution. If global warming is indeed due to our rabid consumption, we may even alleviate its worst effects. Taking precautionary steps and minimizing our carbon footprint makes business sense as well and puts our consumerism on a more sustainable path.
Irrespective of what is causing global warming and the attendant climate changes, lets examine what the consequences would be for Sri Lanka and its wildlife. As a result of the effects of global warming scientists are predicting a temperature rise of between 1.4 to 5.8 degrees Celsius by 2100. The average sea level could rise by between 9 to 88 centimeters. These changes will happen in our lifetimes and certainly during that of our children.
Lets start with the coastal areas and look at a city like Colombo. During the Boxing Day tsunami of 2005 residents in Colombo living around Lake Drive for example noticed how the water rose in the canals and flowed backwards. Colombo and in fact many of our urban centers such as Galle and Matara are low lying areas within a network of wetlands. If sea levels rise, the coastal areas will become increasingly saline and the brackish water zone of mangroves will extend further back. A hundred years from now the Kotte Marshes may no longer be a place to observe freshwater birds such as Purple Swamphen and Pheasant-tailed jacana. It may be a mangrove habitat with Whimbrel, Grey Plover and Bar-tailed Godwit. When I last visited Mannar in February 2005, I birdwatched in what I thought was one of the best wetland sites in Sri Lanka. Ahead of me was stretched a band of pink flamingos. Brown-headed Gull and Caspian Terns patrolled overhead. I was told by a resident that this areas was fertile paddy lands until a cyclone in the 1960s deposited large amounts of sea water. Will rising sea levels convert Colombo to a brackish wetland with hundreds of Flamingos? Perhaps not, if billions are spent to shore up our sea defences.
Ironically the sea shore and marine life will be poorer than richer. The depletion of the ozone layer is allowing more harmful Ultra Violet (UV) radiation to come through. These damage the eggs and larvae of fish, amphibians and other animals. They also cause skin cancers which further adds to the mortality of animals. A number of species may become extinct. The UV is also contributing the formation of ground level ozone which causes respiratory problems. Genetic mutations may result as the UV can damage the DNA of animals. It is not only humans but all living forms will be at risk.
A characteristic flower of Horton Plains National park is the Rhododendron aroboreum. A beautiful red flower in a shrub with leathery leaves. To find other species of Rhododendrons one has to traverse across the mountains of Southern India to the Himalayas 2,500 km. With global warming, montane plants will need to ascend higher up to find the cooler climate to which they have evolved. But there will be no higher up for plants and animals which are already on the roof of Sri Lanka. If the warming is rapid in evolutionary terms, extinction will take place. Extinction may also be the fate of many of our endemic montane animals such as the Dwarf Lizard, Rhino-horned Lizard, Black-lipped Lizard to name a few. Many other animals such as amphibians will have nowhere to go. The highland race of the Purple-faced leaf Monkey (Bear Monkey) may find that their extra fur raises their body temperature too much. Only individuals who by a random variation of genes have a thinner coat may withstand rising temperatures. Dragonflies such as the Red-veined Darter which occurs across to Europe may become locally extinct as the climate and habitat no longer support its favoured niche.
Meanwhile other animals and plants which are adapted for a warmer climate will survive and extend their range up the mountains. But the altitudinal shift in species will only be a gain in range of distribution of species. In terms of the total arithmetic, there may be a significant extinction of our endemic montane plants and animals. A catastrophic extinction event may be happening in our own life time. So remember, little things do count, switch off your lights when you don’t need them.
Gehan de Silva Wijeyeratne (gehan@jetwing.lk) is a writer, photographer and tourism personality on a mission to create a million wildlife enthusiasts. E-mail him to subscribe to his quarterly wildlife e-newsletter.