The devastating floods and loss of life, property and infrastructure in Kerala and parts of Karnataka and Tamil Nadu in the past 10 days have been unprecedented.
Our immediate tasks is to forge partnerships between civil society, volunteers and government agencies for relief and rehabilitation of the affected people. Repair and reconstruction of damaged infrastructure and restoring lost livelihoods will consume the attention of government and society for quite some time.
While such high intensities and sustained spells of rainfall are one of the effects that global warming has on the monsoon, we have to note that this happened after a hundred years and attribution to climate change has to be done with caution.
Recent work on the frequency of intense rain is largely restricted to daily totals but also indicates multi-decadal variability. It highlights an overall increasing trend in daily rain exceeding 150 and 200mm since the early 1900s, though there is a lot of variability over space and time in recent decades.
We must salute the dedication and courage of all those in the government, armed forces, civil society and social media who worked round the clock under difficult conditions to rescue people and arrange for relief.
One of the features of an informed and concerned civil society is drawing the right lessons from disasters so that people make a difference for the future. There are three aspects that are a priority for regions such as the Western Ghats, which are likely to face the brunt of hazards of extreme climate phenomena coupled with land-use.
First, we must take an urgent transparent approach to generation, monitoring and sharing of hydrologic and rainfall data to forge meaningful partnerships between government, academic and civil society to understand the spatial and temporal dimensions of emerging changes in our rainfall regime.
We need to install and maintain automated and tele-connected rain gauges and stream gauges in head water catchments.
This will enable the development of catchment hydrologic models that can predict hydrologic responses at short and longer time scales. The forecasts from such models can be part of the early warning system.
Recent work has brought out the importance of rapid sub-surface pathways that can transfer large quantities of rain in the headwater catchments to streams. This sub-surface watershed residence time decreases non-linearly as rain intensity rises. Projected increases in rainstorm intensity under ongoing climate change would then result in a greater likelihood of river floods in subsurface-dominated watersheds such as in the Western Ghats than is currently simulated by catchment models. Such integrated understanding of how catchments are likely to respond to climatic shocks needs bring together the ministry of earth sciences with that of environment forests and climate change at the centre as well sister agencies at the state level apart from academia and civil society.
The second aspect is that we need a detailed and critical scrutiny of how we monitor and manage our dams and reservoirs as there is sufficient evidence that this has had a bearing on several “flooding" disasters in the country and the need to link adaptive and timely water release to early warning systems and ensuring ecological flows downstream.
The realization that maximising water levels for power production or irrigation can have very dangerous consequences under certain conditions needs to lead to a new policy of adaptive management of our dams and reservoirs linked to upstream early warning systems and downstream needs of ecosystems and livelihoods.
The inevitable trade-offs with respect to hydropower and irrigation will have to be addressed by investments elsewhere in alternative sources and prudent water consumption in agriculture and industry. The evidence that dams can both prevent and cause floods is mounting across the country. We need to rethink our entire approach to large scale transformation of rivers, including their flows and sediment transport and the short and long-term implications of these.
The third aspect we need to highlight is that land-use on steep slopes, low-lying areas where water can converge and vulnerable riparian zones and ecologically sensitive regions needs to be strictly regulated if we are to minimise damage to life, property and the ecosystem. However, environmental activists need to understand the limits of land-use regulations when faced with a climatic shock of such magnitude. The removal of sand from rivers needs to be regulated and alternatives encouraged.
There are other regions and biomes in the country where there is a clear and present danger of climatic or ecological hazards such as sea-level rise as in the deltas and estuaries, large scale dredging of the Ganga and other rivers and landslides, tectonic activity and warming in the Himalayas. We need to mobilise all our knowledge and political will to remould our definitions of what is prudent development and land-use in such regions and biomes.
Jagdish Krishnaswamy is senior fellow at the Ashoka Trust for Research in Ecology and the Environment.