Daily Current Affairs : 30-June-2023
In June 2023, an important study titled “Drift of Earth’s Pole Confirms Groundwater Depletion as a Significant Contributor to Global Sea Level Rise 1993–2010” was published in the journal Geophysical Research Letters. The study shed light on the relationship between groundwater depletion and the shifting of Earth’s axis of rotation, as well as its impact on rising sea levels. This essay aims to explore the findings of the study, analyze its implications, and provide an understanding of the concept of polar motion and the reasons behind it.
Findings: Rise in Sea Levels
Between the years 1993 and 2010, an astonishing amount of approximately 2,150 gigatons of groundwater was extracted by humans for drinking purposes and irrigation. The excessive pumping of groundwater caused a shift in Earth’s axis of rotation, resulting in a movement of 4.36 cm per year towards the east. While this shift may seem significant, it is important to note that it does not have any immediate real-life consequences.
Impact of Groundwater Depletion
Contrary to popular belief, the shift in Earth’s axis caused by groundwater depletion does not directly affect mass changes at the equator or poles. The rotational pole change is primarily associated with the moment of inertia of the Earth, which is sensitive to midlatitude mass change. Therefore, the observed shift does not have a substantial impact on our daily lives.
However, it is essential to acknowledge the indirect consequences of groundwater depletion. The water extracted from the ground for irrigation and fulfilling the world’s freshwater demands eventually finds its way into the oceans. This additional water entering the oceans contributes to the overall rise in sea levels, which is a major concern in the face of climate change and its associated risks.
Understanding Polar Motion
To comprehend the phenomenon of Earth’s pole shift, we must first grasp the concept of polar motion. Earth spins around an imaginary axis that passes through the north pole, its center of mass, and the south pole. This axis and the poles undergo natural shifts as the distribution of mass on and within the planet changes. This natural movement is known as “Polar Motion” and can vary by several meters within a year.
Reasons for Polar Motion
Several factors contribute to polar motion, including geological and environmental factors. Rocks slowly circulating within Earth’s mantle cause the planet’s mass to shift, leading to a change in the position of the rotational axis. Additionally, ocean currents and extreme weather phenomena such as hurricanes can influence polar motion.
Furthermore, climate-driven changes in water mass distribution play a significant role in Earth’s axis drift. The melting of glaciers and ice in Greenland, for instance, leads to a redistribution of water masses, ultimately affecting the position of Earth’s rotational axis.
Important Points:
- Groundwater depletion between 1993 and 2010 resulted in the extraction of approximately 2,150 gigatons of water.
- Excessive groundwater pumping caused a shift in Earth’s axis of rotation, moving it 4.36 cm per year towards the east.
- The shift in the rotational pole caused by groundwater depletion does not have significant real-life consequences.
- Mass changes at the equator or poles do not directly impact the shift in Earth’s axis; rotational pole change is associated with midlatitude mass change.
- The water extracted from the ground for irrigation and freshwater demands eventually enters the oceans, contributing to rising sea levels.
- Polar motion refers to the natural shifting of Earth’s axis and poles as the mass distribution on and within the planet changes.
- Polar motion can vary by several meters within a year.
- Factors contributing to polar motion include rocks circulating within Earth’s mantle, ocean currents, and climate-driven changes in water mass distribution.
- Climate-driven changes in water mass distribution can result from melting glaciers and ice, affecting Earth’s rotational axis.
- While the shift in Earth’s axis caused by groundwater depletion does not directly impact daily life, it contributes to rising sea levels, which is a significant concern in the context of climate change.
Why In News
In June 2023, the groundbreaking study titled ‘Drift of Earth’s Pole Confirms Groundwater Depletion as a Significant Contributor to Global Sea Level Rise 1993–2010’ made waves with its publication in the prestigious journal Geophysical Research Letters. The study’s findings provide compelling evidence that the depletion of groundwater resources during the period from 1993 to 2010 played a substantial role in the observed rise of global sea levels.
Furthermore, this research sheds new light on the intricate dynamics between human activities, climate change, and the Earth’s delicate balance, emphasizing the urgent need for sustainable water management practices to mitigate future sea level rise.
MCQs about Groundwater Depletion
-
What is the primary cause of Earth’s axis shift due to groundwater depletion?
A. Change in mass at the equator
B. Change in mass at the poles
C. Change in midlatitude mass
D. Change in ocean currents
-
Which factors contribute to polar motion?
A. Geological processes
B. Ocean currents
C. Climate-driven changes in water mass distribution
D. All of the above
-
What indirect consequence does groundwater depletion have on rising sea levels?
A. Increase in ocean salinity
B. Expansion of ocean volume
C. Change in oceanic currents
D. Erosion of coastal areas
Boost up your confidence by appearing our Weekly Current Affairs Multiple Choice Questions
