Goaltide Daily Current Affairs 2021
Current Affair 1:
Ancient tree rings shed light on Brahmaputra’s flood risk
A small introduction to Brahmaputra:
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The Brahmaputra River contributes nearly half of the ~40,000 m3/s mean annual discharge of the Ganga–Brahmaputra–Meghna river system. This makes it the joint third largest river system in the world in terms of its mean annual discharge after the Amazon and Congo. Known as the Jamuna in Bangladesh, the high discharge rates of the Brahmaputra are caused, in part, by annual precipitation (rain and seasonal snow) in excess of 3000 mm/year for much of the watershed and snowmelt from its highly glaciated upper basin encompassing the Eastern Himalaya and parts of the Southern Tibetan Plateau. The river and its tributaries provide important societal, ecological, cultural, and economic services to more than 60 million people in Bangladesh, North-eastern India, Bhutan, and Tibet, China. These benefits include fish (a primary source of protein in the region), water to irrigate many seasonal rice varieties that need annual flood waters to survive, the deposition of fresh sediment to sustain the large inhabited riverine islands (known as chars), and the prevention of salt-water intrusion from the Bay of Bengal into the low-lying Sundarban delta |
Scientists warn of underestimating the flood hazard of Brahmaputra by 24 to 38 percent, based solely on natural variations. This means destructive floods will probably be more frequent than scientists have thought.
The concerns come amid reports of China’s and India’s plans to build large-scale hydropower projects on the river.
They call for improved data sharing between the basin states China, India, Bangladesh, Bhutan, and Nepal. The study comes amid reports of China’s and India’s plans to build large-scale hydropower projects on the river.
What is the main concern?
Many researchers agree that a warming climate will intensify the seasonal monsoon rains that drive the Brahmaputra, but the presumed baseline of previous natural variations in river flow rests mainly on discharge-gauge records dating only to the 1950s. However, data from rings of ancient trees in 28 different sites in Tibet, Myanmar, Nepal, and Bhutan in the Brahmaputra River watershed reveal that most recent decades of discharge (1956–1986) are among the driest of the past 700 years.
Anyone using the modern discharge record to estimate future flood hazards would be underestimating the danger by 24 to 38 percent, based solely on natural variations; human-driven warming would have to be added on top of that.
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So, what we should do now? |
The study only talks about flood hazards, one of the three components of flood risk in terms of adaptation. Vulnerability and exposure are the other two. “In terms of policymaking, we can still reduce flood risk by reducing our vulnerability and exposure. So, we need to continue to assess mitigation structures, e.g., embankments, polders, etc. to make sure they can withstand flooding both right now and into the future. Continuing to advance our early warning capabilities and flood action plans would serve us well.
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New projects announced by India and china recently is a threats. |
According to reports, in November 2020, China announced plans to develop nearly 60 GW of hydropower in the lower reaches of the Yarlung Tsangpo (the Brahmaputra in India) amid apprehensions of diversion of water from the river to irrigate drier regions in northwest China. This was followed by reports of India’s announcement on December 1, 2020, to build a 10 GW on the Siang (the stretch of the Brahmaputra in Arunachal Pradesh).
- project may not have such a large impact on wet/monsoon season flows because most of the precipitation originates south of the Himalayas. But any diversion of flow would negatively impact dry season flow which is derived from snow and glacial melt (from the Tibetan Plateau).
- A reduction in dry season flow by a dam would raise water security concerns (not so much of an issue in the wet season) and concerns about saltwater intrusion in the low-lying Sundarbans delta, where a high river discharge rate holds back the ocean’s saline waters. This is again a concern only in the dry season when flow levels are lower.
- An additional layer of worry is associated with dams triggering loss of sediment. The river has one of the highest sediments loads in the world.
- These sediments are crucial to sustaining the floodplain’s fertility (for agriculture) and maintaining the large riverine islands (chars).
- Dams inevitably trap sediments and reduce their load. In the long run, this could threaten the integrity of chars (sandbars or small sandy islands), many of which are currently inhabited.
- The region is active tectonically (earthquakes) and the Brahmaputra is a highly braided (A braided river is a network of small channels separated by islands that are often not fixed) river that migrates its course quite often. Both of these are other large risk factors in addition to flood concerns.
- The poor maintenance of the flood management structures generally causes unexpected miseries to the people in their failure
How tree rings help?
Trees don’t grow their trunk uniformly; though they add a new ring each growing season, trunk growth is closely linked to climate conditions. Under ideal conditions, trees grow quickly, leaving wide annual rings behind. During droughts, unseasonable cold, and other unusual conditions, growth slows, leaving behind narrow rings.
Current Affair 2:
A single-celled organism threatens the vast Arabian sea
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About 970 kilometers northwest of Mumbai on India’s western coast, scientists found themselves sailing on a green swirl that spread out as far as the eye could see. At night, the waters glowed neon blue. The light was emitted by millions upon millions of a single-celled organism: Noctiluca scintillans, or the sea sparkle. It had never been found in these waters in such abundance before. |
The outbreaks occur every winter in the northern Arabian Sea, stretching from India’s western coast to the edges of the boot-shaped Arabian Peninsula.
How it creates problem?
Scientists at Columbia University say they fear the rise of these blooms could herald massive declines in fisheries in the region. It would jeopardize the livelihoods of more than a million fishers living in settlements sprinkled along the coasts of India, Pakistan, Iran, Oman and Yemen.
What is Noctiluca scintillans?
Noctiluca scintillans is plankton that can survive in low-oxygen waters and a growing dead zone in Arabian Sea has allowed the plankton to dominate the area. N. scintillans is a dinoflagellate: it has two strands of antennae-like flagella projecting from its cell membrane. They guide food to its mouth and help it to move.
This is a threat to fish in the area that help sustain 120 million people living on the shores of Oman, India and Pakistan. The plankton is an unusual dinoflagellate that eats other plankton and draws energy from the sun via microscopic algae living within its cells, says the report.
Researchers say that the discharge of nutrient rich sewage from coastal cities is expanding the dead zone and fuelling Noctiluca growth.
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What is the main reason of its boom? |
Current Affair 3:
Two-Dimensional Electron Gas
Scientists have produced electron gas with ultra-high mobility, which can speed up transfer of quantum information and signal from one part of a device to another and increase data storage and memory.
The need for attaining new functionalities in modern electronic devices has led to the manipulation of property of an electron called spin degree of freedom along with its charge. This has given rise to an altogether new field of spin-electronics or ‘spintronics’.
It has been realized that a phenomenon called the ‘Rashba effect’, which consists of splitting of spin-bands in an electronic system, might play a key role in spintronic devices.
Scientists at Institute of Nano Science and Technology (INST), Mohali (Punjab), an autonomous institution of Department of Science and Technology (DST), Government of India, have produced an ultra-high mobility 2d-electron gas(2DEG) at the interface of two insulating oxide layers.
Importance.
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Due to the high mobility of the electron gas, electrons do not collide inside the medium for a long distance and hence do not lose the memory and information. Hence, such a system can easily remember and transfer its memory for a long time and distance. In addition, since they collide less during their flow, their resistance is very low, and hence they don’t dissipate energy as heat. So, such devices do not heat up easily and need less input energy to operate. |
Institute have produced 2DEG with ultra-mobility at the novel interface composed of chemicals EuO and KTaO3. The strong spin-orbit coupling and relativistic nature of the electrons in the 2DEG resulted in the ‘Rashba field’.
According to the INST team, realization of large Rashba-effect at such oxide interfaces containing highly mobile electron gas may open up a new field of device physics, especially in the field of quantum technology applicable for next-generation data storage media and quantum computers.
Current Affair 4:
Pokkali Rice
When Super Cyclone Amphan hit 24 South Parganas district of West Bengal in May last year, it broke embankments, allowing seawater to directly enter the rice fields destroying the crop. Agricultural experts and farmers there started the search for rice varieties that are saline water-resistant and climate change adaptive. Their search finally ended at Ezhikkara, a coastal village on the outskirts of Kochi city in Kerala where a saline tolerant rice variety was being cultivated for several centuries.
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Pokkali Rice has been registered with the Geographical Indications (GI) registry of Government of India in 2008. |
The farming of Pokkali rice does not affect natural ecological process.
Current Affair 5:
Lumpy skin disease
Recently, a Lumpy Skin Disease (LSD) has been infecting India’s bovines. The disease is being reported for the first time in India.
Due to the infectious nature of LSD and its implications on the economy — decreased milk production, abortions and infertility and damaged hides due to cutaneous nodules and fibrous tissue growth cause significant economic losses to farmers — the World Organisation for Animal Health (OIE) declares it as a notifiable disease.
This means a country must inform OIE about any outbreak of the disease so that it can be contained. Yet, no consolidated figure is available with the Department of Animal Husbandry and Dairying (DAHD) regarding the actual spread of LSD in the country or economic losses incurred by farmers.
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