đŸ’„Join UPSC 2027,2028 Mentorship (July Batch) + XFactor Notes & Microthemes PDF
Talk to Mentor

Civilsdaily

Login

Subject: Climate Change

1. Global Warming and Issues
2. All about Pollution

  • [pib] Glacial Lake Atlas of Ganga River Basin

    The Ministry of Jal Shakti has released the Glacial Lake Atlas of Ganga Basin.

    Glacial Lake Atlas

    • The atlas is based on the inventoried glacial lakes in part of the Ganga River basin from its origin to the foothills of the Himalayas covering a catchment area of 2,47,109 sq. km.
    • The study portion of the Ganga River basin covers part of India and the transboundary region.
    • The Atlas is available on National Hydrology Project or NHP-Bhuvan Portal.
    • It can be used by water resources professionals, researchers, disaster management authorities and other stakeholders for managing the glacial lakes as well as to mitigate the possible adverse impacts of GLOF and climate change.

    Expected utility of the atlas is:

    • The atlas provides a comprehensive and systematic glacial lake database for Ganga River basin with size > 0.25 ha
    • In the context of climate change impact analysis, the atlas can be used as reference data for carrying out change analysis, both with respect to historical and future time periods
    • The atlas also provides authentic database for regular or periodic monitoring changes in spatial extent (expansion/shrinkage), and formation of new lakes
    • The atlas can also be used in conjunction with glacier information for their retreat and climate impact studies.
    • The information on glacial lakes like their type, hydrological, topographical, and associated glaciers are useful in identifying the potential critical glacial lakes and consequent GLOF risk.
    • Central and State Disaster Management Authorities can make use of the atlas for disaster mitigation planning and related program.

    Answer this PYQ in the comment box:

    Q.Consider the following Pairs :

    Glacier: River

    1. Bandarpunch : Yamuna
    2. Bara Shigri : Chenab
    3. Milam : Mandakini
    4. Siachen : Nubra
    5. Zemu : Manas

    Which of the following pairs given above are correctly matched? (CSP 2019)

    (a) 1,2 and 4

    (b) 1,3 and 4

    (c) 2 and 5

    (d) 3 and 5

  • Places in news: Yellowstone National Park

    A new assessment of climate change in the Yellowstone National Park shows that it has lost a quarter of its annual snowfall.

    Yellowstone National Park

    • Yellowstone NP is an American national park located in the western United States, largely in the northwest corner of Wyoming and extending into Montana and Idaho.
    • Yellowstone was the first national park in the US and is also widely held to be the first national park in the world.
    • The park is known for its wildlife and its many geothermal features, especially Old Faithful geyser, one of its most popular.
    • While it represents many types of biomes, the subalpine forest is the most abundant. It is part of the South Central Rockies forests ecoregion.
    • The area also represents the one point where the three major river basins of the western U.S. converge.
    • The rivers of the Snake-Columbia basin, Green-Colorado basin, and Missouri River Basin all begin as snow on the Continental Divide as it weaves across Yellowstone’s peaks and plateaus.

    Impact of climate change

    • Since 1950, average temperatures in the Greater Yellowstone Area have risen 1.3°C and potentially, more importantly, the region has lost a quarter of its annual snowfall.
    • The loss of snow there has repercussions for a vast range of ecosystems and wildlife, as well as cities and farms downstream that rely on rivers that start in these mountains.
    • It is home to the southernmost range of grizzly bear populations in North America and some of the longest intact wildlife migrations, including the seasonal traverses of elk, pronghorn, mule deer and bison.

    Answer this PYQ in the comment box:

    Q.Consider the following pairs:

    River                              Flows into

    1. Mekong –                   Andaman Sea

    1. Thames –                     Irish Sea
    2. Volga –                     Caspian Sea
    3. Zambezi –                  Indian Ocean

    Which of the statements given above is/are correct? (CSP 2020)

    (a) 1 and 2 only

    (b) 3 only

    (c) 3 and 4 only

    (d) 1,2 and 4 only

  • Retreating Monsoon is a global phenomenon: Study

    Rainfall during retreating monsoon, which parts of South India experience every year, is not a local anomaly and is global in nature and scale, according to a recent study by the University of Sydney.

    What is Retreating Monsoon?

    • In India, retreating monsoon is the withdrawal of south-west monsoon winds from North India.
    • The withdrawal is gradual and takes about three months.
    • With the retreat of the monsoons, the clouds disappear and the sky becomes clear. The day temperature starts falling steeply.
    • Monsoon rains weaken all over India except few southeastern states.
    • It is helpful in Rabi crop cultivation.

    What has the research found?

    • The research has identified regions in the northern hemisphere that receive the bulk of the rainfall during September, October and November and southern hemisphere that receive most of the rainfall from March to August.
    • The discovery that these are part of a global pattern and not one-off occurrences means they can be systematically studied, which will help understand how these communities could be affected by climate change.
    • Peninsular India and parts of South-East Asia are among the eight regions examined in the study.

    Factors affecting the retreat

    • The eight global regions identified by the study that receive most of their rainfall after summer, have several things in common.
    • They lie on the eastern fringes of landmasses and are in close proximity to mountain ranges with modest heights.

    Two predominant factors cause the phenomenon:

    • First, the low mountain range in each region runs from north to south, shielding it from west-bound winds that trigger summer monsoon.
    • After summer, the range aids in the ‘orographic lift’ or rising of east-bound air mass from a lower to higher elevation, forming clouds and resulting in rain.
    • The second factor is atmospheric convection or vertical movement of air.
    • As the earth is heated by the sun, different surfaces absorb different amounts of energy and convection may occur where the surface heats up very rapidly.
    • As the surface warms, it heats the overlying air, which gradually becomes less dense than the surrounding air and begins to rise.
    • This condition is more favorable from September to February because of the role played by sea surface temperature or water temperature.

    Answer this PYQ in the comment box:

    Q.The seasonal reversal of winds is the typical characteristic of:

    (a) Equatorial climate

    (b) Mediterranean climate

    (c) Monsoon climate

    (d) All of the above climates

  • NatGeo recognizes ‘Southern Ocean’ as globe’s fifth ocean

    The National Geographic magazine has recognized the ‘Southern Ocean’ as the world’s fifth ocean June 8, 2021 hoping others will soon follow suit.

    Answer this PYQ from CSP 2019 in the comment box:

    Q.The most important fishing grounds of the world are found in the regions where:

    (a) warm and cold atmospheric currents meet

    (b) rivers drain out large amounts of freshwater into the sea

    (c) warm and cold oceanic currents meet

    (d) continental shelf is undulating

    Southern Ocean

    • The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica.
    • As such, it is regarded as the second-smallest of the five principal oceanic divisions: smaller than the Pacific, Atlantic, and Indian oceans but larger than the Arctic Ocean.
    • Over the past 30 years, the Southern Ocean has been subject to rapid climate change, which has led to changes in the marine ecosystem.

    What has NatGeo attempted?

    • The magazine says the Southern Ocean is the only ocean ‘to touch three other oceans and to completely embrace a continent rather than being embraced by them’.
    • Its northern limit is a latitude of 60 degrees south.
    • It is also defined by its Antarctic Circumpolar Current that was formed 34 million years ago. The current flows from west to east around Antarctica.
    • The Southern Ocean is home to large populations of whales, penguins, and seals.

    Why such a move?

    • Usually, the magazine has followed the International Hydrographic Organization (IHO) on marine names, it said in an article notifying the change.
    • The IHO too had recognized ‘Southern Ocean’ as a distinct body of water surrounding Antarctica in 1937 but had repealed the same in 1953.

  • [pib] Aerosol Nucleation

    Scientists tracing the concentration, size and evolution of aerosol particles smaller than 3 nanometers at an urban location in India have found the frequent formation of sub-3nm aerosol particles in the atmosphere.

    What is Aerosol Nucleation?

    • The formation of small molecular clusters of sub-3nm size is technically called aerosol nucleation, and subsequent growth of these newly formed clusters to the large sizes is called atmospheric new particle formation (NPF).
    • NPF occurs everywhere in the terrestrial troposphere, and therefore it is a large source of aerosol numbers to the atmosphere.
    • Though extensively studied globally using field observations, laboratory experiments and modelling approach, it is largely unexplored in India.

    What has the new research found?

    • The research showed that a pool of sub-3nm particles is often present in the atmosphere, but how fast these clusters grow depends on various factors.
    • The scientists observed that only half of these events showed newly formed molecular clusters growing past 10 nm size.
    • Thus particle size distributions display a conventional banana-shaped aerosol growth, which is indicative of regional NPF event.

    Role of Sulphur

    • The team found a strong positive correlation between sub-3nm particle concentrations and sulphuric acid concentrations, confirming the potential role of sulfuric acid in the formation of sub-3nm particles.
    • While NPF often starts with sulphuric acid in the atmosphere, sulphuric acid alone fails to explain observed particle formation and growth rates in the atmosphere.
    • Other vapours such as ammonia, amines and organics play a crucial role in the growth of newly formed particles.
    • This has critical importance as a major fraction of these newly formed particles can reach to sizes of cloud condensation nuclei where they have climatic impacts.

  • Glacier melting in Hindu Kush Himalayas

    Up to two billion people in southeast Asia can face food and water shortages even as the Hindu Kush Himalayan (HKH) mountain ranges lose up to two-thirds of its ice by 2100, a United Nations-backed research flagged.

    Hindu Kush Himalayas

    • The HKH region, often referred to as the ‘Third Pole’, is spread over 3,500 square kilometers across eight countries including India, Nepal, and China.
    • The range forms the western section of the Hindu Kush Himalayan Region (HKH) and is the westernmost extension of the Pamir Mountains, the Karakoram, and the Himalayas.
    • It divides the valley of the Amu Darya (the ancient Oxus) to the north from the Indus River valley to the south.
    • It contains the world’s third-largest storage of frozen water after the Antarctica and Arctic.
    • Over 240 million people live in the region’s mountains; 1.7 billion live in the river basins downstream, while food grown in these basins reaches three billion people.

    Continuous warming

    • HKH region continues to warm through 21st century even if the world was able to limit global warming at the agreed 1.5 degrees Celsius.
    • Another study published in 2019 on the ice thickness of glaciers had estimated that glaciers in the HKH may contain 27 percent less ice than previously suggested.
    • The HKH region lies downwind from some of the most heavily polluted places on Earth. This threatens agriculture, climate as well as monsoon patterns.

  • World’s largest iceberg breaks off from Antarctica

    A huge ice block has broken off from western Antarctica into the Weddell Sea, becoming the largest iceberg in the world and earning the name A-76.

    Answer this PYQ in the comment box:

    Q.On the planet earth, most of the freshwater exists as ice caps and glaciers. Out of the remaining freshwater, the largest proportion:

    (a) is found in the atmosphere as moisture and clouds

    (b) is found in freshwater lakes and rivers

    (c) exists as groundwater

    (d) exists as soil moisture

    A-76 Iceberg

    • A-76 is the latest in a series of large ice blocks to dislodge in a region acutely vulnerable to climate change, although scientists said in this case it appeared to be part of a natural polar cycle.
    • The iceberg, measuring around 170 km long and 25 km wide, with an area of 4,320 sq km is now floating in the Weddell Sea.
    • Slightly larger than the Spanish island of Majorca, A-76 had been monitored by scientists since it began to separate from the Ronne Ice Shelf.
    • It joins the previous world’s largest title holder A-23A — approximately 3,880 sq. km. in size — which has remained in the same area since 1986.
    • A-76 was originally spotted by the British Antarctic Survey and the calving — the term used when an iceberg breaks off — was confirmed using images from the Copernicus satellite.

    Note: An iceberg is a large piece of freshwater ice that has broken off a glacier or an ice shelf and is floating freely in open water.

  • Places in news: Leang Sakapao Caves

    Researchers have reported that Pleistocene-era rock paintings dating back to 45,000-20,000 years ago in cave sites in southern Sulawesi, on the Indonesian island of Sulawesi, are weathering at an alarming rate.

    Have you ever found the mention of ‘Altamira Caves’ in your NCERTs?

    Leang Sakapao Caves

    • This cave art of Sulawesi is much older than the prehistoric cave art of Europe.
    • The artwork in the area includes what is believed to be the world’s oldest hand stencil (almost 40,000 years ago), created by pressing the hand on a cave wall and spraying wet red-mulberry pigments over it.
    • A nearby cave features the world’s oldest depiction of an animal, a warty pig painted on the wall 45,500 years ago.

    Impact of climate change

    • The artwork made with pigments was decaying due to a process known as haloclasty, which is triggered by the growth of salt crystals due to repeated changes in temperature and humidity.
    • This is caused by alternating wet and dry weather in the region.
    • Indonesia has also experienced several natural disasters in recent years, which have quickened the process of deterioration.

    Note:

    Mark all islands of the Indonesian Archipelago in your Atlas.

  • Climate change causing a shift in Earth’s axis, finds new study

    About the study

    • A study is published in Geophysical Research Letters of the American Geophysical Union (AGU).
    • The study has added yet another impact of climate change on the earth – marked shifts in the axis along which the Earth rotates.
    • It says that due to the significant melting of glaciers because of global temperature rise, our planet’s axis of rotation has been moving more than usual since the 1990s.

    How the earth’s axis shifts

    • 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, however, as the axis moves due to changes in how the Earth’s mass is distributed around the planet.
    • Thus, the poles move when the axis moves, and the movement is called “polar motion”.
    • Generally, 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.

    What the study says

    • As per the study, the north pole has shifted in a new eastward direction since the 1990s, because of changes in the hydrosphere (meaning the way in which water is stored on Earth).
    • From 1995 to 2020, the average speed of drift was 17 times faster than from 1981 to 1995.
    • The faster ice melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s, the study says.
    • The other possible causes are terrestrial water storage change in non‐glacial regions due to climate change and unsustainable consumption of groundwater.

  • Melting of Glaciers

    Glaciers shrinking faster than before

    • A new study by ETH Zurich and University of Toulouse researchers finds that the world’s glaciers are shrinking at a faster rate than before.
    •  If the trend continues this will put the densely-populated parts of Asia at risk of flood and water shortages.
    • The study found the world’s ice fields lost 298 gigatons of ice per year from 2015 to 2019, a 30% increase in the rate of retreat compared with the previous five years.
    • Glaciers in Alaska, the Alps and Iceland are among those disappearing at the fastest pace.
    • The scientists used images from a special camera aboard NASA’s Terra satellite, which has circled the Earth every 100 minutes since its launch in 1999.

    Impact

    • The situation in the Himalayas is particularly worrying.
    • Swathes of India and Bangladesh could face water stress during dry periods when major rivers like the Ganges and Indus are mainly fed by glacial runoff.
    • Glaciers typically accumulate ice in the winter, but a warming climate means summer melting has outstripped those gains and caused a net loss of ice in mountain regions.
    • The melting in turn contributes to global warming and indirectly accelerates sea level rise, raising the risk of flooding faced by coastal communities.