In recent times, significant climate shifts have been observed in the Kaas Plateau during the Early-Mid-Holocene and Late Holocene periods. These changes have been brought to light through a study carried out by the Agharkar Research Institute (ARI) and the National Centre for Earth Sciences. To understand and unravel the past climatic conditions of the Kaas Plateau, the researchers delved into the study of the sediments of a seasonal lake.
Understanding the Kaas Plateau
The Kaas Plateau, located in Maharashtra’s Satara district, is recognised as a UNESCO World Natural Heritage Site as well as a designated biodiversity hotspot. Fondly referred to as Kaas Pathar in Marathi, its unique name originates from the Kaasa tree, scientifically identified as Elaeocarpus glandulosus belonging to the rudraksha family. In the months of August and September, the plateau boasts an array of vibrant seasonal flowers that form a picturesque floral carpet across the entire lateritic crust.
Pivotal Findings from the Study
The study unearthed several intriguing facets about the environmental history and climatic changes of the Kaas Plateau.
Ancient Lake and Environmental Preservation
Interestingly, the present “Flower Wonder” of the Kaas Plateau sits on an ancient lake which dates all the way back to the Early-Mid-Holocene period—approximately 8000 years ago. This seasonal lake has stood the test of time and offers valuable insights into the region’s past climate.
Climate Shifts during the Early-Mid-Holocene
Approximately 8664 years ago, a turn of events led to a noticeable shift in climate from freshwater to drier conditions characterised by low rainfall. Major changes in the Indian summer monsoon activity were indicated by pollen and diatom data during this time. Despite the prevailing drier conditions, there were intervals of humid periods denoted by a significant increase in the number of diatoms.
Late Holocene Climate Changes
During the late Holocene, around 2827 years ago, rainfall declined and the Southwest Monsoon experienced a weakening phase.
Recent Environmental Impact
In the past 1000 years, evidence of lake Eutrophication has been noted as indicated by the presence of high numbers of planktonic and pollution-tolerant diatom taxa. This phenomenon is a consequence of water bodies becoming overly enriched with minerals and nutrients, leading to excessive growth of algae, also referred to as algal blooms. This, in turn, results in oxygen depletion within the water body. Human activities such as agricultural practices and cattle/livestock farming in the area have contributed significantly to this environmental impact.
Monsoon Intensity and Duration
Around 8000 years ago, during the Early Holocene period, the Southwest monsoon intensified while the Northeast monsoon weakened approximately 2000 years ago. It’s likely that the ‘Flower Wonder’ of the Kaas Plateau enjoyed a longer blooming period, extending up to March-April, during the early-mid-Holocene period (8000-5000 years), when monsoon rainfall was more plentiful, with over 100 rainy days.
