An estimated 25–30 trillion litres of water fell over the state, enough to cause floods even if Kerala’s ecosystem was in pristine condition
Since the Kerala floods hit the headlines, the two questions that many journalists have asked me are, one, was this disaster man-made, and two, what needs to be done to avoid similar devastation in the future?
The answer to the first question is clear: the Kerala floods of 2018 were man-made. But there were two kinds of man-made influences. The first is climate change and the second is the destruction of the local ecology. The extreme rainfall, and hence floods, in Kerala can be attributed to a certain degree to climate change, but the disaster caused by the floods was exacerbated by destruction of the ecology, particularly in the Western Ghats and other ecologically sensitive areas like the nilam (or wetlands).
Let us look at the influence of climate change. In the past 100 years, the average temperature in India has increased by 1.1OC. Other than in the monsoon season, temperature increase in the remaining three seasons has breached the 1.5OC target set in the Paris Agreement. Alongside, there is now clear evidence that extreme rainfall events are increasing. Research by scientists like BN Goswami, Roxy Mathew Koll and others at the Indian Institute of Tropical Meteorology over the last decade shows that high and very high rainfall events are increasing and moderate rainfall events are decreasing.
A recent research paper published in Nature Communications by Roxy and other scientists shows that there has been a threefold increase in widespread extreme-rain events over central India during 1950–2015. Another paper published in Geophysical Research Letters by Vimal Mishra and Haider Ali of IIT-Gandhinagar shows that short-duration extreme rainfall events will further intensify as the global mean temperature rises beyond 1.5OC. If we go by recent experiences, these projections are already a reality in the country.
Over the past 15 years, many parts of the country have been battered by extreme rainfall events. The flood that crippled Mumbai in 2005 was caused by extreme rainfall of 994 mm in 24 hours. Similar extreme rainfalls devastated Leh in 2010, Uttarakhand in 2013, Jammu and Kashmir in 2014, Chennai in 2015 and Saurashtra in 2017.
Kerala, too, experienced unusually high rainfall. The average rainfall in the month of August was two and a half times the normal. On August 15 and 16, the rainfall for the entire state was about 140 mm/day, which is probably the highest ever. During the eleven days of rainfall, an estimated 25–30 trillion litres of water fell over the state. This is so much water that it would have caused floods even if Kerala’s ecosystem was in
But, Kerala’s ecosystem is far from pristine. The destruction of Kerala’s ecology over the past 60 years has been unprecedented. This can be gauged by the change in land use in the state over the past half a century. Three major transformations can be clearly identified: one, Kerala has lost a massive amount of natural forests (estimated to be in excess of 4 lakh hectares) and wetland (in excess of 2.5 lakh hectares) to agriculture, plantation and infrastructure development. Two, land used for non-agricultural purposes (mostly for housing and infrastructure) has more than doubled in the last 50 years. In the last 10 years itself, Kerala has diverted 70,000 hectares of land for housing and infrastructure. Three, traditional crops like rice and tapioca have been replaced with plantations of rubber and other commercial crops. These drastic changes in land use have destroyed the watershed, impeded the flow of rainwater and reduced the ability of the land to soak water. All these factors aggravated the floods.
What should we do to prevent similar destruction in the future? I will answer this question in two parts. First, what Kerala should do and, second, what the country should do.
Kerala should set up a State Flood Commission to evolve a comprehensive approach to manage extreme rainfall in the state. This commission should examine the impact of major land use changes on the hydrology of the state. It should also look at the dam management systems. Besides this, district-level sub-commissions should be set up to identify the areas where roads, railways, hydropower, embankments and other infrastructure projects aggravated flood problems and suggest mitigation measures.
Kerala should relook the Gadgil committee and the Kasturirangan committee reports. It has put forth objections to both reports and tried to reduce the area under ecologically sensitive zones (ESZs). It is time for it to re-evaluate its position regarding ESZs. Similarly, Kerala should also develop an action plan to conserve and enhance its wetlands.
As a country, we need to improve our environmental governance while working with other countries to halt global warming. First, our environmental governance is failing to protect the environment. All kinds of regulations—environment, forest, wildlife, coastal regulations, land use—are flouted with impunity. In fact, there is no credible deterrence for non-compliance. This must change.
Second, climate change will destroy communities, devastate the economy and heavily stress the stability and security of the country. To minimise the impacts, we must start adapting to climate change. This will require putting adaptation at the centre of our development policies and processes.
But, there is a limit to adaptation. Beyond a certain temperate increase, our ecosystem and economy cannot adapt. So, we must halt global warming. But there is no indication that the world is collectively doing enough to reduce emissions of greenhouse gases.
The anti-climate sentiments in the US has deflated the global effort to combat climate change. As developing countries like India will suffer the most because of global warming, it is time that India takes leadership and works with other countries to reduce emissions. We must do our best to ensure that the global temperature increase remains well within 2OC. Climate change is a clear and present danger. The quicker we accept and internalise this, the better off we will be.
-The author is Deputy director general of Centre for Science and Environment (CSE)