Semi-arid ecosystems in India: Current and future concerns
By Jagdish Krishnaswamy with inputs from Milind Bunyan and Rajiv Chaturvedi
This year climate change issues rode in on an ominous and ferocious sequence of weather events in South Asia. The Westerlies carrying moisture from far away western seas and oceans caused heavy rain in January, especially in north India. As winter lead to summer, we had unusually heavy rains right through the dry-season, damaging crops all over India. This was followed by a searing heat wave that killed thousands in India and even more in Pakistan; the majority of people affected were the poor and the vulnerable. Global warming and climate change has dominated the popular and scientific discourse.
Then we had the official forecasters predicting “normal” rain but changing their prediction to a weak Monsoon influenced by El Niño. However, after a delayed start which worried many, the Monsoon covered all parts of India, a few weeks ahead of its “normal” schedule, and the heavy rains initially seemed to dispel earlier gloomy predictions of a weak Monsoon. But now in some of our study sites in south India and Maharashtra there seems to be a lull in the monsoon, after some intense spells and heavy flows in rivers initially. Farmers are reporting withered crops in the traditional semi-arid areas.
In India, often semi-arid areas, including our three study sites, are all downstream of the Western Ghats, a region that has seen the highest rates of decline in the Monsoon since 1950 (Figure 2) and has been exposed to higher rates of warming as well (Figure 3). Furthermore agriculture in semi-arid areas has seen increasing reliance on dams and exploitation of groundwater to grow water-intensive crops like sugarcane. These dams that fail miserably in drought years, sometimes cater to the sugarcane industry rather than farmers and herders, and groundwater exploitation has exceeded recharge rates. On the positive side, some states such as Tamil Nadu have recently started a new initiative on organic farming, which will hopefully address major concerns about unsustainable water and harmful chemical use in agriculture.Whether the Monsoon will get stuck in July and weaken in the remaining months is a matter of great interest and concern. This reminds us of the observed weakening of the Monsoon in India over many decades, and the fact that climate models have not been able to simulate it (Figure 1), although their predictions of increase in frequency of more intense rain and increasing temperature are consistent with recent trends.
Semi-arid regions and socio-ecological systems in India have also been neglected in terms of conservation strategies that are biased towards forested regions. Furthermore, native trees that grew or were grown around farmland and in commons are disappearing, only to be replaced with invasive and fast growing exotics, posing a threat to biodiversity and ecosystem services. Along with climate change, these changes in semi-arid ecosystems will need our attention.
Finally, the boundaries of semi-arid regions with respect to humid and sub-humid regions could be shifting in response to climate change. The dynamics of these shifts and their implications for ecosystem services, livelihoods and vulnerability of communities will need detailed scrutiny from ASSAR and other researchers.