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3rd May 2021
Shift in Earth’s axis due to Climate Change
Recently, a study published in Geophysical Research Letters of the American Geophysical Union (AGU) has stated that the planet’s axis of rotation has been movingmore than usual due to climate change.
Process of shifting of Earth’s axis
- The Earth’s axis of rotation is the line along which it spins around itself as it revolves around the Sun.
- The points on which the axis intersects the planet’s surface are the geographical north and south poles.
- The location of the poles is not fixed because the axis moves due to changes in how the Earth’s mass is distributed around the planet.
- The poles move when the axis moves, and the movement is called “polar motion”.
- According to NASA, data from the 20th century shows that the spin axis drifted about 10 centimetres per year.
- The polar motion is caused by changes in the hydrosphere, atmosphere, oceans, or solid Earth but now, climate change is adding to the degree with which the poles wander.
- The climate change has caused billions of tonnes of glacial ice to melt into oceans which has caused the Earth’s poles to move in new directions.
- As per the study, the North Pole has shifted in a new eastward direction since the 1990s, because of changes in the hydrosphere.
- The average speed of drift was 17 times faster from 1995 to 2020 as compared to 1981 to 1995.
- The calculations were based on satellite data from NASA’s Gravity Recovery and Climate Experiment (GRACE) mission as well as estimates of glacier loss and groundwater pumping.
- The faster ice melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s.
- The other possible causes are (terrestrial water storage) change in non‐glacial regions due to climate change and unsustainable consumption of groundwater for irrigation and other anthropogenic activities.
- It was selected as the second mission under the NASA Earth System Science Pathfinder (ESSP) Program in May 1997.
- It was launched in 2002.
- It is a joint partnership between the National Aeronautics and Space Administration (NASA) in the United States and Deutsche Forschungsanstalt für Luft und Raumfahrt (DLR) in Germany.
- It was aimed at accurately mapping variations in the Earth's gravity field over its 5-year lifetime.
- Its objective was to map the Earth's gravity fields by making accurate measurementsof the distance between the two satellites, using GPS and a microwave ranging system.
- The gravity variations that GRACE were:
- changes due to surface and deep currents in the ocean;
- runoff and ground water storage on land masses;
- exchanges between ice sheets or glaciers and the oceans; and
- variations of mass within the Earth.
- It was first released in 1984.
- It is a three-dimensional groundwater model that simulates solute transport (i.e. salt water) or temperature in a subsurface environment.
- It is a model for saturated-unsaturated, variable-density ground-water flow with solute or energy transport.
- The SUTRA (Saturated-Unsaturated Transport) is a computer program that simulates fluid movement and the transport of either energy or dissolved substances in a subsurface environment.
- It employs a weight grid that is based on a finite element and integrated finite difference hybrid method framework.
- It has been used to simulate the effects of saltwater intrusion, contaminant transport, and thermal pollution.
- An amount of Rs.8873.6 crore has been released to the States.
- It is constituted under the section 48 of (1) (a) of Disaster Management Act 2005.
- It is a primary fund available with State Government for responses to notified disaster.
- The Central Government contributes 75% of SDRF allocation for general category States/UTs and 90% for special category States.
- The annual contribution is released in two equal instalments as per the recommendation of the finance commission.
- The State Government may use up to 10% of the funds available under SDRF for providing immediate relief to the victims of the natural disaster that day considered to be “Disaster” within the local contacts in the State.
- SDRF shall be used only for meeting the expenditure for providing immediate relief to the victims.
- The disasters covered under SDRF are Cyclone, Drought, Earthquake, Floods, Tsunami, Hailstorm, Landslide, Avalanche, Cloud burst, Pest attack, Frost and Cold wave.
- It is constituted in the Public Account under the Reserve Fund.
- The state government shall pay the interest to the SDRF at the rate applicable to overdraft regulation guidelines of the RBI.
- The nodal ministry for overseeing and monitoring the operations under SDRF is Ministry of Home Affairs.
- The audit the SDRF is carried out by Comptroller and Auditor General of India (CAG) on annual basis.
- The share of the Government of India to the SDRF shall be paid as grant-in-aid.