Study traces high rainfall in Northern Bay of Bengal than the other parts of India for the last 10000 yearsJanuary 20, 2023↓
Source: The post is based on the article “Study traces high rainfall in Northern Bay of Bengal than the other parts of India for the last 10000 years” published in PIB on 19th January 2023.
What is the News?
According to a study, regions surrounding the Northern Bay of Bengal(BoB) received higher precipitation than the other parts of India for the last 10,200 years.
About India’s Dependence on Monsoon
Agriculture in India is heavily dependent on the Indian Summer Monsoon rains(ISMR).
The Bengal Basin or the ‘Bengal region’ being located at the trajectory of the Bay of Bengal (BoB) branch of the ISM is very sensitive to changes in the Indian Summer Monsoon(ISM) strength.
Even a minor change in ISM strength may have adverse effects on the agrarian-based socioeconomic conditions of the region.
About the study on Indian Summer Monsoon Rainfall(ISMR)
The study traced the dynamics of Indian Summer Monsoon Rainfall(ISMR) over the 10000 years – a period which witnessed the development and fall of numerous ancient civilizations around the world, many of which were associated with climate instability.
It found that regions surrounding the northern Bay of Bengal(BoB) received higher precipitation than the other parts of India for the last 10200 years.
The study also explored the drivers influencing the variability of the monsoon in the Indian part of the Bengal Basin. It found that:
– Millennial-scale variations in the ISMR may largely be attributed to changes in solar insolation and dynamics of Inter tropical Convergence Zone (ITCZ– area where the northeast and the southeast trade winds converge)
– Centennial scale variations may be collectively triggered by phenomena like North Atlantic Oscillation, El Nino Southern Oscillation and Indian Ocean Dipole.
New plateau type discovered from Maharashtra could prove to be a repository of information to study climate change effects on species survivalJanuary 20, 2023↓
Source: The post is based on the article “New plateau type discovered from Maharashtra could prove to be a repository of information to study climate change effects on species survival” published in PIB on 19th January 2023.
What is the News?
Researchers have discovered a rare low-altitude basalt plateau in the Western Ghats that could offer new insights into surviving climate change.
What is the importance of the Western Ghats?
The Western Ghats is one of four global biodiversity hotspots in India.
Plateaus are dominant landscapes in the Western Ghats, significant because of the predominance of endemic species.
They are classified as a type of rock outcrop and provide a unique and challenging environment for species to adapt to.
These outcrops have seasonal water availability, limited soil and nutrients, making them ideal laboratories to study the effects of climate change on species survival
What did the researchers discover at the Western Ghats?
Researchers discovered a rare low-altitude basalt plateau in Manjare village, Thane district, Maharashtra.
This is the fourth type of plateau to be identified in the region; the previous three are laterites at high and low altitudes and basalt at high altitudes.
Surveying the plateau, the researchers documented 76 species of plants and shrubs from 24 different families.
The authors believe this is an important discovery, as the plateau shares the vegetation with the three other rock outcrops, simultaneously holding a few unique species.
Hence, this plateau can prove to be a repository of information for species interactions. It can also help study the effects of climate change on species survival and increase awareness of the conservation needs of rock outcrops and their immense biodiversity value in the global context.
Etalin Hydroelectric Project: Temporary relief as plan for Etalin hydel in Arunachal junkedJanuary 20, 2023↓
Source: The post is based on the article “Temporary relief as plan for Etalin hydel in Arunachal junked” published in Down To Earth on 19th January 2023.
What is the News?
The proposed Etalin hydroelectric project in Arunachal Pradesh has been scrapped in its present form.
What is the Etalin Hydroelectric Project?
Etalin Hydroelectric Project is envisaged as a run-of-the-river scheme on rivers Dri and Tangon in the Dibang Valley District of Arunachal Pradesh.
– Note: Dir and Tangon are both tributaries of the Dibang River (tributary of Brahmaputra).
It was proposed to be developed as a joint venture between Jindal Power Ltd and the Hydropower Development Corporation of Arunachal Pradesh Ltd.
What are the concerns related to the Etalin Hydroelectric Project?
Environmental concerns: The project will require the diversion of 1,165.66 hectares of forest land and the felling of more than 280,000 trees in the area.
– The Forest Advisory Committee(FAC) highlighted that the land in which the project is proposed covers two pristine forests with riverine growth that, once cut, cannot be replaced.
Displacement of people: The project would displace thousands of people from their homes and livelihoods, many of whom are from indigenous communities who rely on those rivers for their livelihoods.
Seismic Risks: The South Asia Network on Dams, Rivers and People (SANDRP) highlighted the geological and seismic risks and threats to biodiversity in 2015 when environmental clearance (EC) for the project was underway.
Chamundi Hills: Citizens’ committee to press for heritage panel clearance for work on Chamundi HillsJanuary 20, 2023↓
Source: The post is based on the article “Citizens’ committee to press for heritage panel clearance for work on Chamundi Hills” published in The Hindu on 20th January 2023.
What is the News?
The citizens committee to save the Chamundi Hills have urged the government to conserve and promote the religious sanctity and environmental integrity of Chamundi Hills.
They have said that the funds under the Pilgrimage Rejuvenation and Spiritual, Heritage Augmentation Drive(PRASHAD) scheme should not be utilized for creating concrete structures under the guise of new amenities at Chamundi Hills.
What is PRASHAD Scheme?
What is Chamundi Hills?
Chamundi Hill is located in Mysore, Karnataka. The famous Chamundeswari Temple is located in the hills.
The temple was named after Chamundeshwari or, the fierce form of Shakti. It is believed that Goddess Durga slayed the demon king Mahishasura on the top of this hill which was ruled by him.
The place was later known as Mahishooru (Place of Mahisha). The British changed it to Mysore and later Kannadized it into Mysuru.
Karanji lake is the most popular lake in Chamundi Hills. The lake is owned by the Mysore Zoo.
Europe’s largest known deposit of rare earth elements found in Sweden: Could the discovery change geopolitics?January 18, 2023↓
Source: The post is based on the article “Europe’s largest known deposit of rare earth elements found in Sweden: Could the discovery change geopolitics?” published in Indian Express on 18th January 2023.
What is the News?
Swedish state-owned mining company, LKAB has announced that it has discovered more than one million tonnes of rare earth oxides in the northern area of the country. This is the largest known deposit in Europe.
What are rare earth metals?
What are rare earth metals used for?
These elements are important in technologies of consumer electronics, computers and networks, communications, clean energy, advanced transportation, healthcare, environmental mitigation, and national defense among others.
For instance, 1) Scandium is used in televisions and fluorescent lamps, 2) yttrium is used in drugs to treat rheumatoid arthritis and cancer and 3) Cerium, the most abundant rare earth element, is essential to NASA’s Space Shuttle Programme.
Why has demand for rare earth metals increased in recent years?
In recent years, there has been an increase in demand for green energy. Hence the demand for elements like neodymium and dysprosium, which are used in wind turbine motors, has increased.
Also, the push for switching from internal combustion cars to electric vehicles has also led to a rise in demand for rare earth magnets — made from neodymium, boron, and iron — and batteries.
What does this rare earth metals discovery mean for Europe and the world?
Relief for European countries: Against the backdrop of the fraught relations between China and other western countries, the new discovery of a deposit of rare earth elements in Sweden has come as a relief for the latter.
Challenges China’s monopoly: Currently, no rare earths are mined in Europe and it mostly imports them from other regions. According to a report, 98 percent of rare earths used by the European Union were sent by China.
– China has repeatedly used its monopoly in the rare earths market for furthering its geopolitical agendas. In 2010, China blocked Japan’s access to rare earth elements over Tokyo’s detention of a Chinese fishing trawler captain.
Strengthens Minerals Security Partnership(MSP): In 2022, the US and 10 other partners came together for this alliance known as MSP. The goal of the MSP is to secure supply chains of critical minerals, aimed at reducing dependency on China. This discovery in Sweden will give a boost to the partnership.
Reconstructing past deep-water circulations of Indian OceanJanuary 17, 2023↓
Source: The post is based on the article “Reconstructing past deep-water circulations of Indian Ocean” published in The Hindu on 15th January 2023.
What is the News?
Studies have indicated that tectonically driven changes in the ocean gateways had a dramatic impact on the Global Overturning Circulation(GOC).
What is Global Overturning Circulation(GOC)?
It is the equatorward transport of cold, deep waters and the poleward transport of warm, near-surface waters.
It controls ocean heat distribution and atmospheric carbon dioxide levels, thus playing a critical role in global climate.
What was the impact of tectonic changes in ocean gateways on ocean circulation?
Studies have indicated that tectonically driven changes in the ocean gateways such as the closure of the Central American Seaway, a body of water that once separated North America from South America, since the late Miocene period, had a dramatic impact on ocean circulation.
These changes may have led to the creation of two distinct water bodies: 1) Northern component water in the North Atlantic Ocean and 2) Antarctic Bottom Water (AABW) in the Southern Ocean.
Consequently, it is also hypothesized that there would have been large-scale changes in the Deep-Water Circulation (DWC) in the oceans across the world, impacting global climate and heat exchanges. But these formulations have remained untested due to a lack of adequate data.
What about deep water circulations of the Indian Ocean?
The Indian Ocean does not produce its own deep water, it only receives it from other sources such as the North Atlantic and Antarctic.
The northern part of the Indian Ocean is located far away from the areas where deep water is formed and ocean routes, making it a good place to study the impact of ocean circulation changes.
Studies have been done in the Indian Ocean to understand past deepwater circulation using records from iron-manganese crusts and the authigenic neodymium isotope composition of sediment cores.
But these records have certain limitations such as data being available only for the Bay of Bengal region and Himalayan rivers bringing a substantial amount of neodymium particulates.
How did the new study overcome these limitations?
A new study by a team of researchers has generated an authigenic neodymium isotope record from the Arabian Sea and reconstructed the DWC record of the Indian Ocean for the period from 11.3 million years ago (Miocene era) to 1.98 million years ago (Pleistocene era).
The record shows a clear shift from the Pacific water-dominated deep circulation system about nine million years ago, to the onset of a modern-like deep water circulation system in the Indian Ocean comprising of Antarctic bottom water and northern component water during the Miocene-Pliocene transition (about six million years ago).
The finding suggests a widespread impact of the late Miocene Central American Seaway closure on the evolution of ocean deep water circulation and validates the so-called Panama Closure Hypothesis.
What is Panama Closure Hypothesis?
The “Panama Hypothesis” states that the gradual closure of the Panama Seaway, between 13 million years ago (13 Ma) and 2.6 Ma has led to decreased mixing of Atlantic and Pacific water Masses.
This led to the formation of North Atlantic Deep water and strengthening of the Atlantic thermohaline circulation, increased temperatures and evaporation in the North Atlantic and increased precipitation in Northern Hemisphere (NH) high latitudes.
Joshimath sank by 5.4 cm in 12 days, says ISRO reportJanuary 14, 2023↓
Source: The post is based on the article “Joshimath sank by 5.4 cm in 12 days, says ISRO report” published in The Hindu on 13th January 2023
What is the News?
According to images released by the National Remote Sensing Centre (NRSC) of the Indian Space Research Organisation(ISRO), Uttarakhand’s Joshimath has witnessed a rapid subsidence of nearly 5.4 cm in the past 12 days.
What is Subsidence?
Why is Joshimath sinking?
Joshimath town has great religious, spiritual and cultural importance. It is home to the monastery of Adi Sankaracharya and the gateway to the Badrinath temple.
However, it is built on the deposits of an old landslide which means the slopes can be destabilized even by slight triggers.
The town is also in Zone V, denoting the highest risk, in India’s seismic zonation scheme.
Hence, Joshimath’s geological setting together with the unplanned and rampant construction in and around the town has resulted in land subsidence.
Atmospheric rivers: California’s record-breaking storm: What is the ‘Pineapple Express’ phenomenon underlying itJanuary 12, 2023↓
Source: The post is based on the article “California’s record-breaking storm: What is the ‘Pineapple Express’ phenomenon underlying it” published in the Indian Express on 12th January 2023.
What is the News?
Forecasters in the US have said that the rain arriving in California is caused by a “true Pineapple Express” -a specific example of a common atmospheric phenomenon resembling a conveyor belt for moisture.
Note: The global conveyor belt is a “constantly moving system” in the ocean driven by changes in temperature and salinity.
What are atmospheric rivers?
Atmospheric rivers are long, narrow regions in the atmosphere that transport most of the water vapor outside the tropics.
Occurance: These rivers in the sky often occur on the US’s West Coast but can happen in other locations, including the eastern United States.
Moisture content: These rivers often channel moisture from the Caribbean. They carry a lot of moisture which is enough to equal or sometimes exceed the average flow of the Mississippi River at the point where it flows into the Gulf of Mexico.
How do atmospheric rivers aid rainfall or storms?
When atmospheric river moisture begins to interact with land, it can fall as rain or snow. These rivers provide a continuous flow of moisture so, the precipitation will usually be abundant.
According to the NOAA, between 30% and 50% of the annual precipitation on the US’s West Coast occurs from just a few atmospheric river events.
Over the past two weeks, California and other parts of the West Coast have been hit with a series of atmospheric rivers.
What are atmospheric river families, and what are their impacts?
When the atmospheric rivers come back-to-back then they are called “atmospheric river families”. The effects can be serious, like extensive flooding.
What is a true Pineapple Express?
Atmospheric rivers come in different shapes and sizes. A Pineapple Express is a strong atmospheric river that builds up in the tropical pacific, according to the NOAA.
Some necessary conditions for pineapple express are, a) The moisture is pulled from the tail end. This tail end must start near Hawaii, b) The river must stretch continuously through the atmosphere to the U.S. West Coast.
3,700 dams in India will lose 26% storage capacity due to sedimentation by 2050: UN studyJanuary 11, 2023↓
Source: The post is based on the article “3,700 dams in India will lose 26% storage capacity due to sedimentation by 2050: UN study” published in Economic Times on 10th January 2023
What is the News?
According to a study by the United Nations, around 3,700 dams in India will lose 26% of their total storage by 2050.
This study was conducted by the United Nations University Institute on Water, Environment and Health (UNU-INWEH) also known as the UN’s think tank on water.
What are the key findings of the study?
Dams in India: Around 3,700 large dams in India will lose 26% of their total storage by 2050 due to the accumulation of sediments which can undermine water security, irrigation and power generation in future.
– Note: In 2015, the Central Water Commission reported that among 141 large reservoirs which are over 50 years old, one quarter had lost at least 30% of their initial storage capacity.
Dams Globally: Trapped sediment has already robbed roughly 50,000 large dams worldwide of an estimated 13 to 19% of their combined original storage capacity.
– The study estimates that 6,316 billion cubic meters of initial global storage in 47,403 large dams in 150 countries will decline to 4,665 billion cubic metres causing 26% storage loss by 2050.
– This loss is roughly equal to the annual water use of India, China, Indonesia, France and Canada combined.
Dams in Asia Pacific region: In 2022, the Asia-Pacific region, the world’s most heavily dammed region, is estimated to have lost 13% of its initial dam storage capacity. It will have lost nearly a quarter (23%) of its initial storage capacity by 2050.
– This region is home to 60% of the world’s population and water storage is crucial for sustaining water and food security.
Dams in China: China, the world’s most heavily dammed nation has lost about 10% of its storage and will lose a further 10% by 2050.
Joshimath crisis: What is land subsidence and why does it happen?January 10, 2023↓
Source: The post is based on the article “Joshimath crisis: What is land subsidence and why does it happen?” published in Indian Express on 9th January 2023
What is the News?
Joshimath, Uttarakhand has been declared as a landslide and subsidence-hit zone.
What is Land Subsidence?
According to the National Oceanic and Atmospheric Administration(NOAA), subsidence is the sinking of the ground because of underground material movement.
It can happen for a host of reasons, man-made or natural, such as the removal of water, oil, or natural resources, along with mining activities. Earthquakes, soil erosion, and soil compaction are also some of the well-known causes of subsidence.
The subsidence can happen over very large areas like whole states or provinces, or very small areas like the corner of your yard.
Must read: Land subsidence: PMO reviews situation in ‘sinking’ Joshimath town
What can be the reasons behind Joshimath’s subsidence?
Firstly, Joshimath city has been built on an ancient landslide material — meaning it rests on a deposit of sand and stone, not rock, which doesn’t have high load-bearing capacity. This makes the area extremely vulnerable to ever-burgeoning infrastructure and population.
Secondly, the lack of a proper drainage system might have contributed to the sinking of the area. Experts say that unplanned and unauthorized construction has led to the blocking of the natural flow of water, which eventually results in frequent landslides.
Thirdly, subsidence might have been triggered by the reactivation of a geographic fault — defined as a fracture or zone of fractures between two blocks of rock — where the Indian Plate has pushed under the Eurasian Plate along the Himalayas.
Fourthly, the incident might have occurred because of unplanned construction, over-population, and obstruction of the natural flow of water and hydel power activities.
Fifthly, residents have blamed NTPC’s Tapovan Vishnugad Hydro Power Project for the incident. They allege that the tunnel had water seepage from a punctured aquifer, leading to the drying of water sources in Joshimath.
Settlement on debris is primary reason for ‘sinking’, states reportJanuary 9, 2023↓
Source: The post is based on the article “Settlement on debris is primary reason for ‘sinking’, states report” published in TOI on 9th January 2023
What is the News?
The Uttarakhand town of Joshimath which is located at the foothills of the Himalayas, has been reportedly “sinking”, with cracks visible on the walls of the houses and structures.
Why is Joshimath sinking?
Joshimath is a small town in Uttarakhand which is located at the foothills of the Himalayas, and on the site of an ancient landslide.
The reasons why Joshimath sank a few inches under the ground are:
Firstly, the prime reason is the geography of the place. Since the city has been established on landslide debris, the land has a low bearing capacity, and it cannot sustain a large amount of construction and population.
Secondly, unplanned construction, population pressure, tourist infrastructure, hydel power projects and development activities have also made the slopes highly unstable in the last couple of decades.
Thirdly, the lack of systematic drainage has compounded the problem. Unregulated construction has often come in the way of the natural flow of water because of which water has had to chart alternative routes. Due to this, a lot of water has been percolating down into the porous crystalline rocks beneath the surface softening them further.
Land subsidence: PMO reviews situation in ‘sinking’ Joshimath townJanuary 9, 2023↓
Source: The post is based on the article “PMO reviews situation in ‘sinking’ Joshimath town” published in The Hindu on 8th January 2023
What is the News?
Joshimath has been declared a Landslide-subsidence zone and over 60 families living in uninhabitable houses in the sinking town have been evacuated to temporary relief centers.
What is land subsidence?
The United States Geological Survey describes Land Subsidence as a gradual settling or sudden sinking of the Earth’s surface due to the removal or displacement of subsurface earth materials.
Subsidence is most often caused by the removal of water, oil, natural gas, or mineral resources out of the ground by pumping, fracking, or mining activities. This feature can also be caused by natural events such as earthquakes, soil compaction, erosion and sinkhole formation.
What is the risk of Land Subsidence?
Experts estimate that by 2040, land subsidence will affect 8% of the world’s surface and an approximate 1.2 billion people living in 21% of the major cities across the globe.
It is also said that land subsidence will impact Asia more than other parts of the world. With 86% of the Asian population exposed to the effects of land subsidence, about $8.17 trillion is potentially at stake.
What are the effects of Land subsidence?
Land subsidence can cause the settlement of clay on the upper levels — leading to damage of infrastructure (roads, bridges) and flooding due to ineffective drainage systems of the city.
Experts cite that it could impact houses and other infrastructure, making them weaker, and also lead to the weakening of foundations or development cracks in the buildings (such as the Joshimath incident).
Half of glaciers will disappear by 2100 even if world sticks to 1.5°C goal: StudyJanuary 9, 2023↓
Source: The post is based on the article “Half of glaciers will disappear by 2100 even if world sticks to 1.5°C goal: Study” published in Down To Earth on 7th January 2023
What is the News?
According to a study titled “Global glacier change in the 21st century: Every increase in temperature matters”, half of the Earth’s glaciers are destined to vanish by 2100.
Note: Glaciers, which hold 70 % of the Earth’s freshwater, currently encompass around 10% of the planet’s land area.
About the study on Glacier melting
Glaciers are receding at unprecedented rates due to climate change and rising temperatures. The amount of ice lost by glaciers between 1994 and 2017 was around 30 trillion tonnes and they are now melting at a pace of 1.2 trillion tonnes each year.
The glaciers in the Alps, Iceland and Alaska are some of those that are melting at the quickest rates.
Half the Earth’s glaciers are destined to vanish by 2100, even if we adhere to the Paris Climate Agreement goal of limiting global temperature rise to 1.5 degrees Celsius above pre-industrial levels.
A minimum of 50% of the loss will occur within the next 30 years. 68% of glaciers will vanish if global warming continues at the current rate of 2.7 °C.
If this happens, by the end of the following century, there would be practically no glaciers left in central Europe, western Canada and the United States.
Impact of Glacier melting
Glacier melting will significantly contribute to sea level rise, threaten the supply of water of up to 2 billion people, and increase the risk of natural hazards such as flooding.
Around 60% of India prone to earthquakesDecember 24, 2022↓
Source: The post is based on the article “Around 60% of India prone to earthquakes” published in Down To Earth on 23rd December 2022
What is the News?
The Union minister for science and technology has informed Lok Sabha that around 59% of the landmass of India (covering all states) is prone to earthquakes of different shaking intensities.
What is an Earthquake?
About Earthquake Risk in India
According to the seismic zoning map of India prepared by the Bureau of Indian Standards (BIS), India has been divided into four zones – II, III, IV and V.
Zone V is seismically the most active region while Zone II is the least.
Around 11% of the country falls in Zone V, 18% in Zone IV, 30% in Zone III and the remaining in Zone II.
What is the other news covered in the article?
Coal-based power: Over the years, the share of coal in the total primary energy mix has increased from about 42% in 2009-10 to 45.56% in 2020-21.
– More than 72% of the electricity generated in the country is coal-fired (including lignite).
Landless tribal households in northeast India: According to the Socio-Economic and Caste Census (SECC) 2011 report, around 59% of rural households in northeast India have no land.
Kepler-138c and Kepler-138d: Scientists detect two water worlds 218 light years awayDecember 19, 2022↓
Source: The post is based on the article “Scientists detect two water worlds 218 light years away” published in Down To Earth on 18th December 2022
What is the News?
A team of researchers has announced that two previously discovered exoplanets Kepler-138c and Kepler-138d are Water Worlds which means they are primarily made of water.
In 2014, astronomers discovered three exoplanets orbiting Kepler-138, a star 218 light years from Earth.
They observed two of these exoplanets Kepler-138c and Kepler-138d with Hubble and the retired Spitzer space telescopes.
What were the key findings of the researchers?
The unique factor of the two exoplanets was that watery liquid makes up a large part of their composition.
Notably, water on these exoplanets wasn’t detected directly. Researchers compared the sizes and masses of the planets to conclude that a significant fraction of their volume — up to half of it — should be made of materials that are lighter than rock but heavier than hydrogen or helium — and water is the most common material that fits that criteria.
The closest comparisons to these water worlds are Europa and Enceladus — icy moons orbiting Jupiter and Saturn, respectively — but because Kepler-138 c and Kepler-138 d are so much closer to their star, their water would not be frozen.
What is the Geminids meteor shower, and where can you watch itDecember 14, 2022↓
Source: The post is based on the article “What is the Geminids meteor shower, and where can you watch it” published in Indian Express on 14th December 2022
What is the News?
In 2022, the Geminids will peak around December 13-14, when, with a clear sky and away from bright city lights, one can watch scores of meteors streak across the sky.
What is a Meteor Shower?
Meteors are bits of rocks and ice ejected from comets as they move in their orbits about the sun.
A meteor shower occurs when the Earth passes through the trail of debris left by a comet or asteroid.
Approximately 30 meteor showers occur each year that are visible to observers on Earth. Some of these showers have been around longer than 100 years.
What is a Geminids Meteor Shower?
Geminids are one of the best and most reliable annual meteor showers. If their peak coincides with the new moon, and if the weather is clear, the Geminids can produce approximately 100-150 meteors per hour for viewing.
Origin of name: Geminids Meteor Shower comes from the constellation Gemini, from whose location in the sky the meteor shower appears to originate
Significance: The Geminids are unique because, unlike most meteor showers, they originate not from a comet, but from an asteroid, the 3200 Phaethon.
– Note: The 3200 Phaethon was discovered on October 11, 1983. It is named after the Greek mythology character Phaethon, son of the Sun God Helios. It takes 1.4 years to complete one round of the Sun.
Changing Arctic: New insight on freeze-melt cycle of sea iceDecember 9, 2022↓
Source: The post is based on the article “Changing Arctic: New insight on freeze-melt cycle of sea ice” published in Down To Earth on 8th December 2022
What is the News?
According to a study, the surface and bottom of the Arctic sea ice often do not melt and freeze simultaneously.
About Arctic Sea Ice
The Arctic sea ice is seasonal. It forms in the winter when seawater freezes into massive floating ice blocks and thaws during the summer. When sea ice is present, it insulates the ocean against heat loss.
The sea ice reflects sunlight into space, regulating ocean and air temperature and maintaining habitats above and below the water.
Understanding the timings of the thawing of sea ice and freeze onsets, as well as the lengths of the melt and freeze seasons is crucial. These play a vital role in the “heat budget” of the atmosphere-ice-ocean system.
Note: A heat budget is a balance between incoming heat absorbed by the earth and outgoing heat escaping it.
What did the study find on the Arctic Sea Ice?
Until now, most studies calculated the Arctic melt and freeze onsets using remote sensing observations from the surface, but rarely investigated the freeze-thaw process at the ice bottom.
The researchers have now analyzed data from 2001 to 2018 to explore how melting and freezing vary at the ice surface and bottom.
They found that the surface and bottom of the Arctic sea ice often do not melt and freeze simultaneously. For instance, at the Beaufort Gyre — a major ocean current in the Arctic Ocean — the average ice melt at the bottom is approximately 17 days earlier than the surface melt onset.
This longer melt season under the ice is likely playing a key role in the enhanced thinning of the ice that is keeping the summer extents low.
Semeru Volcano: Alert at highest level in Indonesia as volcano eruptsDecember 7, 2022↓
Source: The post is based on the article “Semeru Volcano: Alert at highest level in Indonesia as volcano erupts” published in Indian Express on 6th December 2022
What is the News?
Semeru volcano has erupted in Indonesia’s Eastern Java Island.
What is Mount Semeru?
Mount Semeru is an active volcano located in East Java, Indonesia. This volcano is also known as Mahameru, meaning “The Great Mountain” in Sanskrit.
It is located in a subduction zone, where the Indo-Australian plate subducts under the Eurasia plate. It is the highest mountain on the island of Java.
Note: Indonesia is prone to seismic upheaval due to its location on the Pacific’s Ring of Fire.
What is the Pacific Ring of Fire?
Scientists urge Andhra Pradesh govt. to protect glacial-period coastal red sand dunes of VizagDecember 5, 2022↓
Source: The post is based on the article “Scientists urge Andhra Pradesh govt. to protect glacial-period coastal red sand dunes of Vizag” published in The Hindu on 5th December 2022
What is the News?
Geologists have urged the Andhra Pradesh Government to protect the site of Coastal Red Sand Dunes, of Visakhapatnam, Andhra Pradesh.
What are Coastal Red Sand Dunes?
Coastal red sand dunes are popularly known as Erra Matti Dibbalu.
The site is located along the coast and is about 20 km northeast of Visakhapatnam city and about 4 km southwest of Bheemunipatnam in Andhra Pradesh.
Distribution: Such red sand deposits are rare and have been reported only from three places in the tropical regions in South Asia such as Teri Sands in Tamil Nadu, Erra Matti Dibbalu in Visakhapatnam and one more site in Sri Lanka.
– They do not occur in equatorial regions or temperate regions due to many scientific reasons.
Recognition: This site was declared a geo-heritage site by the Geological Survey of India (GSI) in 2014.
– The Andhra Pradesh government listed it under the category of ‘protected sites’ in 2016.
Features: The uniqueness of this site is that the red sediments are a part of the continuation of the evolution of the earth and represent the late quaternary geologic age.
– With a height of up to 30 m, they exhibit badland topography with different geomorphic landforms and features, including gullies, sand dunes, buried channels, beach ridges, paired terraces, the valley in the valley, wave-cut terrace, knick point and waterfalls.
What is the significance of this site?
Firstly, this site is about 18,500 to 20,000 years old and it can be related to the last glacial period. Hence, studying this site can help understand the impact of climate change as this site has seen both the glacial and the warm periods.
Secondly, this site has archaeological significance, as studies of artifacts indicate an Upper Palaeolithic horizon and on cross dating assigned to Late Pleistocene epoch, which is 20,000 BC.
– The site was also home to the pre-historic man as the excavations at several places in the region revealed stone implements of three distinctive periods and also the pottery of the Neolithic man.
Perfect storm: What is the Fujiwhara Effect?November 28, 2022↓
Source: The post is based on the article “Perfect storm: What is the Fujiwhara Effect?” published in Down To Earth on 28th November 2022.
What is the News?
Meteorologists were mesmerized by Typhoon Hinnamnor as it provided a textbook example of a phenomenon known as the Fujiwhara Effect.
What is the Fujiwhara Effect?
The Fujiwhara Effect is any interaction between tropical storms formed around the same time in the same ocean region with their centres or eyes at a distance of less than 1,400 km with the intensity that could vary between a depression (wind speed under 63 km per hour) and a super typhoon (wind speed over 209 km per hour).
The interaction could lead to changes in the track and intensity of either or both storm systems. In rare cases, the two systems could merge, especially when they are of similar size and intensity, to form a bigger storm.
Identified by: The Fujiwhara effect was identified by Sakuhei Fujiwhara, a Japanese meteorologist whose first paper recognising the Fujiwhara cases was published in 1921.
Sukapaika River: Breathing life into a dead river in OdishaOctober 26, 2022↓
Source: The post is based on the article “Breathing life into a dead river in Odisha” published in The Hindu on 25th October 2022
What is the News?
The Sukapaika River which stopped flowing 70 years ago is set to be rejuvenated as the Odisha government has started working on its revival plan following a recent direction from the National Green Tribunal(NGT).
What is the Sukapaika River?
Sukapaika is one of the several distributaries of the mighty Mahanadi river in Odisha.
The river originated from Mahanadi river near Ayatpur village in Cuttack. It flowed 27.50 km before meeting the Mahanadi again at Bankala.
When it was flowing freely, Sukapaika river acted as a source of drinking water, irrigation and other livelihood opportunities to over 425 villages under 26-gram panchayats.
Why has the river dried up?
In the 1950s, the Odisha government closed the Sukapaika river mouth enabling the development of the Taladanda Canal System, a major canal of the State.
This led to the river dying a painful death and the process was aggravated by agricultural encroachments that had sprung up on the riverbanks.
Thamirabarani: Govt, ATREE adopt ‘hyper local’ approach to restore one of south Asia’s oldest riversSeptember 28, 2022↓
Source: The post is based on the article “Thamirabarani: Govt, ATREE adopt ‘hyper local’ approach to restore one of south Asia’s oldest rivers” published in Down To Earth on 28th September 2022
What is the News?
The district administration of Tirunelveli in Tamil Nadu along with Bengaluru-based non-profit Ashoka Trust for Research in Ecology and the Environment (ATREE) are using a ‘hyper local’ approach to restore Thamirabarani River.
What is the Thamirabarani River?
Thamirabarani is the only perennial river in Tamil Nadu.
It originates in the Pothigai Hills of the Western Ghats in Tirunelveli district.
The river flows through Tirunelveli and then neighbouring Thoothukudi and ends in the Gulf of Mannar at Punakayil. It thus originates and ends in the same state.
Significance: The river supports wildlife such as the Nilgiri marten, slender loris, lion-tailed macaque, white spotted bush frog, galaxy frog, Sri Lankan Atlas moth and the great hornbill.
– Besides the ecosystem services it provides, the river also has historical value for the people of the state. It is mentioned extensively in Sangam Era literature.
Threats: The river is stressed because of industrial effluent release, sewage and water hyacinth. Initial study suggests that the river gets polluted due to industrial discharge and the dumping of solid waste, especially in the form of clothes and flowers by devotees.
What is the TamiraSES project?
Launched by: District administration of Tirunelveli in Tamil Nadu along with Bengaluru-based non-profit ATREE.
Aim: To restore the Social Ecological Systems of the Tamiraparani riverscape from head-waters to the estuary to enable conditions for native biodiversity to thrive and maintain and enhance multiple ecosystem services to local stakeholders.
– Five social ecological observatories will be set up as part of the first phase of the project. These will serve as pilots to scale up from the learnings from these sites.
– The idea is to rejuvenate not just the Thamirabarani but all the water bodies in the riverscape of Tirunelveli.
Advanced Dvorak Technique(ADT): How this cyclone intensity estimation technique saved millions of lives across continentsSeptember 26, 2022↓
Source: The post is based on the article “How this cyclone intensity estimation technique saved millions of lives across continents” published in Indian Express on 23rd September 2022
What is the News?
American meteorologist Vernon Dvorak, credited for developing the Advanced Dvorak Technique(ADT) in the 1970s, has passed away.
What is Advanced Dvorak Technique(ADT)?
Advanced Dvorak Technique(ADT) is a widely used system to estimate tropical cyclone intensity.
This technique utilizes the available satellite images obtained from polar-orbiting satellites to examine the features of the developing tropical storms (hurricanes, cyclones and typhoons).
During the daytime, images in the visible spectrum were used while at night, the ocean would be observed using infrared images.
Note: This technique cannot help make any predictions, or measure wind or pressure or any other meteorological parameters associated with the cyclone. But it is a guide to estimate the storm’s intensity and possible intensification.
What is the significance of this technique?
This technique is said to be one of the greatest meteorological innovations. Even in the present day, when forecasters have access to several state-of-the-art tools like model guidance, animations, artificial intelligence, machine learning and satellite technology, this technique continues to be widely used.
Explained: What is ‘Arth Ganga’, govt’s new model for the river’s sustainable developmentAugust 26, 2022↓
Source: The post is based on the article “Explained: What is ‘Arth Ganga’, govt’s new model for the river’s sustainable development” published in Indian Express on 25th August 2022.
What is the News?
Director General of the National Mission for Clean Ganga spoke about the Arth Ganga model during his virtual keynote address to the Stockholm World Water Week 2022.
Note: Since 1991, the Stockholm International Water Institute has been organizing World Water Week every year to address global water concerns.
What is Arth Ganga?
Origin: In 2019, PM first introduced the concept of Arth Ganga during the first National Ganga Council meeting in Kanpur where he urged for a shift from Namami Gange (cleaning of Ganga) to the model of Arth Ganga.
Definition: The Arth Ganga focuses on the sustainable development of the Ganga and its surrounding areas, by focusing on economic activities related to the river.
– The Arth Ganga model seeks to use economics to bridge people with the river. It strives to contribute at least 3% of the GDP from the Ganga Basin itself.
Features: Under Arth Ganga, the government is working on six verticals:
1. Zero Budget Natural Farming: It involves chemical-free farming on 10 km on either side of the river, and the promotion of cow dung as fertilizer through the GOBARdhan scheme.
2. Monetization and Reuse of Sludge & Wastewater: It seeks to reuse treated water for irrigation, industries and revenue generation for Urban Local Bodies (ULBs).
3. Livelihood Generation Opportunities by creating haats where people can sell local products, medicinal plants and ayurveda.
4. Increase public participation by increasing synergies between the stakeholders involved with the river.
5. Promote the cultural heritage and tourism of Ganga and its surroundings, through boat tourism, adventure sports and conducting yoga activities.
6. Promote institutional building by empowering local administration for improved water governance.
Explained: The Kali Bein and its significance for SikhsJuly 22, 2022↓
Source: The post is based on the article “Explained: The Kali Bein and its significance for Sikhs” published in Indian Express on 22nd July 2022.
What is the News?
Punjab Chief Minister has been admitted to Delhi’s Apollo Hospital days after he had drunk a glass of water directly from the Kali Bein.
What is Kali Bein?
Kali Bein is a holy rivulet (a small stream) in Sultanpur Lodhi, Punjab.
The rivulet starts from Hoshiarpur, runs across four districts and meets the confluence of the rivers Beas and Sutlej in Kapurthala.
Along its banks are around 80 villages and half a dozen small and big towns. Wastewater from there as well as industrial waste used to flow into the rivulet via a drain turning its waters black, hence the name Kali Bein(black rivulet).
What is the significance of Kali Bein to the Sikh religion?
The Kali Bein is of great significance to Sikh religion and history because the first Guru, Nanak Dev, is said to have gotten enlightenment here.
When Guru Nanak Dev was staying at Sultanpur Lodhi with his sister Bebe Nanki, he would bath in the Kali Bein. He is said to have disappeared into the waters one day, before emerging on the third day. The first thing he recited was the “Mool Mantra” of the Sikh religion.
Oceans Great Dying 2.0: Mass extinction haunts oceansJune 28, 2022↓
What is the News?
Scientists warn of imminent mass extinction of marine species similar to one that happened 250 million years ago during the Permian Era.
What is the Permian Era?
The Permian era is a period spanning 298.9 million-252.2 million years ago. This was a time before the dinosaurs ruled the planet. Global ocean temperatures were 10 degrees higher than today. Oxygen levels were 80% lower.
During this period, land masses collided to form the supercontinent Pangaea. The supercontinent was arid; only a few parts received rainfall round the year.
However, the large Panthalassic Ocean which covered much of Earth was home to many marine and terrestrial species.
But towards the end of the era, a series of volcanic eruptions occurred in central Siberia, injecting massive amounts of greenhouse gases(GHG) into the atmosphere.
The change in climate after the volcanic eruptions was a death knell for the flourishing and diverse life forms.
Many long-lived lineages vanished. Roughly 96% of marine species and 70% of land species went extinct. Hence, the scientists refer to this period as the ‘Great Dying’.
Why are scientists warning of Great Dying 2.0?
Scientists have warned of Great Dying 2.0 because climate change that happened at the end of the Permian era is similar to the one that is unfolding now.
They have said that if emissions continue to climb and temperatures reach around 4.9 degrees Celsius by the end of this century, close to about 40% of marine genera could perish by 2300 and 8% by 2100.
Source: The post is based on the article “Oceans Great Dying 2.0: Mass extinction haunts oceans” published in Down To Earth on 27th June 2022.