by T. V. Padma, Mongabay
- A recent study finds that out of 634 districts considered, only 38 percent were found resilient to dry conditions, while there was a significant reduction in water use efficiency for some of the districts.
- This finding adds to another study that determined resilience of 55 water catchments around the country and found that catchments dominated by human activities were less resilient.
- Experts feel that incorporating ground realities (as against remotely sensed data) and the socio-economic context into resilience is crucial when making projections for the future.
Less than half of India is resilient to dry conditions and there is a significant reduction in water use efficiency in several districts across the country, new research shows.
Out of 30 states and union territories in India, only 10 states had more than 50 percent resilient area. “The results of this study highlight the need for better ecosystem management policies in the country,” the study says.
Their report says that carbon and water cycles play an important role in ecosystem functioning and are interlinked through different physical and biological processes. Disturbances in the various climate factors that impact water habitats, or hydroclimatic disturbances, for example, droughts, affect both the water cycles and ecology of the land.
Both the water cycles and ecological processes will be adversely affected by increasing disturbances caused by climate change. And how an ecosystem withstands these changes, its resilience, will, in turn, impact the sustainability of the ecosystem, the report says.
The scientists assessed the resilience of land ecosystems in India to hydro-climatic disturbances, at the district scale that is an administrative unit. In their report, the scientists defined ecosystem water use efficiency (WUEe), as the ratio of net primary productivity or NPP (how much carbon dioxide a plant takes in during photosynthesis minus carbon dioxide released during respiration) to evapotranspiration (the amount of water lost from the soil or plants leaves).
The scientists used this ratio an indicator of ecosystem functioning or its response to hydroclimatic disturbances.
They found a large spatial variation in water use efficiency in India at district scale. It was significantly higher in lower Himalayan regions compared to rest of the country and there was an increasing trend in water use efficiency in central India.
The scientists also measured resilience in terms of the ratio of the water use efficiency under dry conditions; and the mean water use efficiency which indicates the ability to absorb hydroclimatic disturbance.
Out of 634 districts considered for this study, only 241 (38 percent) were found resilient to dry conditions, whereas there was a significant reduction in water use efficiency for some of the districts.
The scientists say that the resilience at district scale indicates the response of ecosystems across biomes or large ecological communities with distinctive plants and animals. “In general, the forest dominated districts had higher resilience compared to districts dominated by other biome types. Also, districts having temperate climate were found having higher resilience,” write the authors in the paper.
Sanjeev Bhuchar, watershed management specialist at the International Centre for Integrated Mountain Development (ICIMOD), Kathmandu, finds the study and its methodology “timely and useful.” ICIMOD’s own medium-term action plan from 2018 to 2022 states “that there is a gap in the HKH (Hindu Kush-Himalayan region) with regard to understanding what factor combinations would contribute to resilience building in different socio-ecological contexts,” he said.“Therefore, research on this topic is an immediate priority,” said Bhuchar.
“There is a lack of WUE (water use efficiency) and ecosystem resilience assessments in the HKH,” he added. “NPP (net primary productivity) related studies, vulnerability assessments of different forest stands, agroforestry systems and others are available, but not from WUE and resilience perspective.”
The Hindu Khush Himalayan Monitoring and Assessment Programme (HIMAP) too reports the HKH region has seen “significant warming in past decades, slightly higher than, or nearly equal to, the global average – a trend that will continue,” said Bhuchar.
This might lead to increased evaporation rates and more drought or drought-like conditions, along with increased water runoff due to intense precipitation. It is therefore important to understand through research how current and future terrestrial systems (considering also the changes in vegetation patterns due to climate change) respond to hydroclimatic factors for actionable information.
Against this backdrop, the new research and their methodology “is very timely and useful,” said Bhuchar.
“It has high relevance for the HKH for adaptation planning and developing metrics for measuring, monitoring and evaluating “resilience”. The research also highlights the potential of advanced earth observation systems and geospatial methods to gain insights into regional scenarios to characterise ecosystem system conditions and changes.
“In terms of building on this research, it would be also interesting to go deeper into the impacts of higher WUE of certain forest ecosystems during dry spells on water resources, especially aquifers,” added Bhuchar.
The need for resilience with a social relevance
Not all concur with the Journal of Hydrology study’s approach or interpretation. Sharadchandra Lele, distinguished fellow in environmental policy and governance, Ashoka Trust For Research in Ecology and The Environment (ATREE), Bengaluru, observes that “the concept of resilience is a complex one, but if it is a socially relevant goal, then it must be measured in socially relevant terms”. The socially relevant goals include well-being and socially useful production and WUE itself may not be a socially relevant outcome.
Resilience means the ability of a system as measured in terms of a socially relevant goal to bounce back after stress or a shock, he said.
But, said Lele, the ratio of total net primary productivity or NPP to total evapo-transpiration, used in the study, is “a poor measure of socially relevant production.” And the comparison of dry year water use efficiency to average water use efficiency “tells us little about the ability to bounce back after a dry year: it becomes a measure of stability or resistance to climatic stress.”
“The coarseness of the measure can reveal nothing about what attribute of a system builds resilience,” said Lele. “It appears as though some regions simply are resilient and others are not. But all of India is hugely affected by human activities, such as cultivation, irrigation, urbanisation, and fossil energy utilisation. What practices enhance or reduce resilience is something this analysis cannot tell us.”
Lele says that the use of satellite data to derive both net primary productivity and evapo-transpiration without any ground validation studies raises questions. For instance, the results indicate that Punjab, Haryana and the entire Uttar Pradesh have an annual evapotranspiration of just a few 100 mm. “This is quite doubtful, given that this is the breadbasket of the country with multiple irrigated crops in a year,” said Lele.
“The complete dependence on remotely sensed data combined with the lack of socialisation of the concept of resilience makes the value of this analysis rather doubtful,” added Lele.
The resilience of water catchments
The study adds to insights gained in previous resilience studies. A study by Goyal and colleagues, published in Nature Communications in September, looked at resilience of 55 water catchments areas across India. It observed that “any sustainable hydrological response to climate warming would highlight the resilience of that catchment.”
It reported that 23 catchments displayed hydrologic resilience to climatic warming shifts. Only 37.14 percent of catchments dominated by human activities (higher contribution from human activities) were found to be resilient, compared to 58.82 percent of climate-dominated catchments that saw relatively less human activities.
Most of the catchments on western and extreme southern part of India were not hydrologically resilient, this study reported. “Extensive human interactions tend to depart the catchment from expected hydrological functioning,” their report said.
The study on India’s catchments says that human interactions will affect the partitioning of rainfall at the catchment scale and “that human activities would have a good hand in controlling the resilience of a catchment under climate warming.”
Since, India is the second most populated country in the world, it has a huge demand for fresh water which further results in increasing the gap between freshwater demand and supply, the report says.
It says that India’s booming economy in recent years have accelerated urbanisation and industrialisation and this led to changes in land use and land cover (LULC) in most parts of the country. Examples of extensive LULC changes include Hyderabad in Telangana state and the Hasdeo river basin in the northern part of Chhattisgarh state which has also undergone a tremendous LULC change from degradation of dense forest (loss of up to 7.52 percent) to increase in non-forest (up to 8.59 percent) and open forest land (up to 3.55 percent).