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Subject: Climate Change

1. Global Warming and Issues
2. All about Pollution

  • [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.

  • Delhi’s air quality deteriorates, again

    Air quality to oscillate between poor to very poor

    • Delhi’s air quality deteriorated from ‘moderate’ to ‘poor’ and ‘very poor’ on April 29.
    • It will be oscillating between ‘poor’ and ‘very poor’ for the next three days, according to the SAFAR-System of Air Quality and Weather Forecasting and Research.
    • Delhi’s air typically worsens in October-November and improves by March-April.

    What is the cause

    • Current weather conditions are not unfavourable, unlike in winter.
    • Hence, apart from local emissions, the deterioration in air quality is being attributed to an increase in fire counts, mostly due to burning of wheat crop stubble in northern India.
    • Deteriorating air quality is worrying amid an increasing number of novel coronavirus disease (COVID-19) and deaths.

    Quality classification

    • An AQI between 0-50 is considered ‘good.
    • An AQI between 51-100 is considered satisfactory.
    • An AQI between 101-200 is considered moderate.
    • An AQI between 201-300 is considered poor.
    • An AQI between 301-400 is considered very poor.
    • An AQI between 401-500 is considered severe.
    • Above 500 is the ‘severe-plus’ or ‘emergency’ category.

  • Major oil and gas producers form Net Zero Producers’ Forum

    About the Net Zero Producers’ forum

    • Five of the world’s major oil and gas producers are working together to ‘develop pragmatic net-zero emission strategies’.
    • Qatar, the US, Saudi Arabia, Canada and Norway, collectively responsible for 40% of global oil and gas production, will come together to form a cooperative forum that will develop pragmatic net zero-emission strategies.
    • Energy producers are faced with unique responsibilities to furnish the world with energy but the climate crisis requires serious leadership and a strong alliance to deliver a path to net-zero.

    Strategies and technologies

    • The Net Zero Producers’ Forum will consider strategies and technologies which include methane abatement, circular carbon economy approach, development and deployment of clean energy and carbon capture and storage technologies, diversification from reliance on hydrocarbon revenues etc.

    Source:

    https://www.energy.gov/articles/joint-statement-establishing-net-zero-producers-forum-between-energy-ministries-canada

  • Limited sops make scrappage policy for vehicles unattractive

    Why the Vehicle Scrappage Policy is unattractive

    • The policy proposes to de-register vehicles that fail fitness tests or are unable to renew registrations after 15-20 years of use.
    • Limited incentives and poor cost economics for trucks in the Vehicle Scrappage Policy, coupled with lack of addressable volumes for other segments is unlikely to drive freight transporters to replace their old vehicles with new ones, said a Crisil report.
    • Though the scrappage volume of buses, PVs and two-wheelers is expected to be limited as well, the policy’s impact on new commercial vehicle (CV) sales could be sizeable, based on addressable volume, ratings agency Crisil Research said in its report.
    • The potential benefit from scrapping a 15-year-old, entry-level small car will be ₹70,000, whereas its resale value is around ₹95,000. That makes scrapping unattractive, Crisil said in the report.

  • Eastern India most vulnerable to climate change, says study

    About the report

    • Published this week, the report on ‘Climate vulnerability assessment for adaptation planning in India using a common framework’ was conducted in 2019-2020 across 29 States.
    • It was part of a capacity building programme under the National Mission on Sustaining the Himalayan Ecosystem and National Mission on Strategic Knowledge for Climate Change.
    • The report was prepared by IISc, IIT-Mandi and IIT-Guwahati.

    Major findings

    • Along with Chhattisgarh in central India, Jharkhand, Mizoram, Odisha, Assam, Bihar, Arunachal Pradesh, and West Bengal are the eight most vulnerable States.
    • These eight most vulnerable States require prioritisation of adaptation interventions.
    • Jharkhand, with the highest vulnerability indices VI of 0.674, topped the list of States most vulnerable to climate change.
    • The major drivers for the vulnerability of all the States included lack of forest area per 1,000 rural population, lack of crop insurance, marginal and small operational land holding, low density of health workers, low participation of women in the workforce, yield variability of food grains, and a high proportion of the population below the poverty line.
    • Tamil Nadu and Kerala are among seven States that are the least vulnerable but there’s more to it meets the eye.
    • However, the vulnerability indices (VIs) for these seven States range from the lowest of 0.419 for Maharashtra to 0.468 for Uttarakhand, which is on the higher side.