Groundwater ‘time bomb’ is ticking

Context: Future generations face an environmental “time bomb” as the world’s groundwater systems take decades to respond to the present day impact of climate change, scientists have warned.

What’s the issue?

As per the findings by an international team of researchers, groundwater reserves are already under pressure as the global population explodes and crop production rises in lockstep. But the extreme weather events such as drought and record rainfall — both made worse by our heating planet — could have another long-lasting impact on how quickly reserves replenish.

Why is the crisis described as a time bomb?

Researchers found that only half of all groundwater supplies are likely to fully replenish or re-balance within the next 100 years — potentially leading to shortages in drier areas. This could be described as an environmental time bomb because any climate change impacts on recharge occurring now, will only fully impact the baseflow to rivers and wetlands a long time later.

The process through which rainwater is filtered through bedrock and accumulated underground can take centuries and varies greatly by region. As climate change delivers longer droughts and bigger superstorms, the extremes of rainfall become more pronounced, impacting groundwater reserves for generations to come. In arid areas took far longer — several thousand years in some cases — to respond to alterations in climate than reserves in more humid parts.

Situation of groundwater in India:

Today, India is the largest user of the groundwater in the world with almost 90% being used for drinking water and almost 60-70% for irrigation. Current statistics also show that nearly 50% of urban water supply comes from groundwater. India is on the threshold of a very serious groundwater crisis, which needs mitigation both in the fields and at the policy corridors of the country.

The groundwater crisis is embedded at two different levels:

1. Groundwater exploitation of aquifers (where groundwater is stored) in different parts of the India and
2. Groundwater contamination that find origins, both in geogenic source such as Arsenic and Fluoride along with anthropogenic sources of contamination primarily due to poor disposal of waste and wastewater.

Concern:

Water scarcity, poor water quality and inadequate sanitation negatively impact food security, livelihood choices and educational opportunities for poor families across the world. Drought afflicts some of the world’s poorest countries, worsening hunger and malnutrition.

Need of the hour:

There is a need to modernise the regulatory framework for accessing groundwater soon after massive expansion in mechanical pumping led to the realisation that recharge could not keep pace with use.

Sources: the hindu.