A new study has revealed that soil moisture depletion has significantly contributed to the rise in global mean sea level (GMSL), highlighting its impact on the water cycle, agriculture, and climate systems. Between 1979 and 2016, the loss of soil moisture led to a 10.78 millimetre increase in sea levels, equivalent to 3,941 gigatonnes of water loss from terrestrial sources. The research, cited by DownToEarth, indicates that this trend has become irreversible since 2003 and has continued to intensify in the years that followed.

From 2003 onwards, soil moisture depletion has caused an additional 2.76 mm rise in sea level, corresponding to another 1,009 gigatonnes of lost land water. These findings establish a direct connection between land water loss and rising oceans, indicating a more complex climate change feedback mechanism than previously understood.

Soil moisture plays a key role in the Earth's hydrological and energy cycles. It regulates temperature, supports vegetation, and influences weather patterns. As soil dries, less water is available to evaporate, which can cause land surfaces to heat up more quickly, affecting local and regional climates. Prolonged periods of low soil moisture also contribute to the severity and duration of droughts, which can harm ecosystems, reduce agricultural productivity, and limit water availability for human use.

Changes in weather patterns, particularly in monsoon-affected regions, have also been tied to shifting soil moisture conditions. Variability in rainfall, including more frequent floods and prolonged dry spells, affects soil retention capacity and leads to greater fluctuations in moisture levels. This not only reduces crop yields but also hampers groundwater recharge, a vital source of water in many parts of the world.

Experts have noted that understanding soil moisture trends is crucial for improving weather and climate prediction models. Surface and sub-surface soil moisture measurements are essential for accurate climate forecasting, agricultural planning, and monitoring of hydro-meteorological conditions. However, due to the scarcity of ground-based observation systems, comprehensive data on soil moisture trends remains limited.

The study further outlines how soil moisture impacts temperature regulation, especially in regions such as north-central India, where changes in surface moisture have contributed to rising temperatures. Additionally, the decline in groundwater levels in various regions is being driven by multiple factors including changes in precipitation, agricultural water use, urban development, and declining soil moisture levels.

With the dual threat of rising sea levels and intensifying droughts, the study underscores the importance of prioritising soil moisture monitoring in climate strategies. Soil water loss is not just a local agricultural concern but a global issue with far-reaching effects on sea levels, food security, and water availability.

These findings highlight the need for enhanced soil monitoring infrastructure, particularly in vulnerable regions. Improved satellite data, coupled with ground-level measurements, could help develop early warning systems for drought and floods, better inform water resource management, and support climate adaptation strategies.

As global temperatures continue to rise, the feedback loop between soil moisture loss and climate impacts is likely to grow more severe. Without coordinated international efforts to monitor and mitigate soil degradation and manage water resources sustainably, the risks to food production, human health, and environmental stability will continue to escalate.

Source: DownToEarth