13 Nov

Table of contents

1   Feature Article


Extreme Events and Relationship with Climate Change

2   News in Brief


Cyclone Gulab: An exceptional Cyclone in the Bay of Bengal


Deteriorating air quality in Delhi- the menace of winter smog

3   Key Terms


Natural Capital




Tarn lakes

4   Case Study of The Week


Rice-fish farming – a potential venture of livelihood security for the tribal community of East Siang district

5   Places in the News


Harike Wildlife Sanctuary

.... Show less Show more
Feature Article

Extreme Events and Relationship with Climate Change

  • In news: According to State of the Climate in Asia report, India along with China and Bangladesh recorded most of the extreme event disaster-related displacement globally in 2020.


  • Background:
  • According to IPCC -AR6, changing climate leads to changes in the frequency, intensity, spatialextent, duration, and timing of weather and climate extremes.
  • While many weather and climate extremes are the result of natural climate variability (includingphenomena such as El Niño), and natural decadal or multi-decadal variabilities, it is theanthropogenicactivities which are the driving force in climate change.
  • As a consequence,average temperatures have risen by 1.2Ccomparedtopre industrialera. This additional energy is unevenlydistributed and bursts out in extremes events disasters like hurricanes, heat-waves, cloud bursts, droughts etc.

For example: some of the extreme events that have been experienced around the world in 2021 are:

  • A heat wave in Canada and adjacent parts of the USA pushed temperatures to nearly 50C in a village in British Columbia.
  • Death Valley, California reached 54.4C during one of multiple heat waves in the south-western USA.
  • A second successive year of drought in sub-tropical South America reduced the flow of river basins and hit agriculture, transport and energy production.
  • Climate change relationship with increasing extreme events:
  • How climate change contributes to drought: With climate change the equilibrium of water cycle will shift. The Standardized Precipitation-Evapotranspiration Index, indicate more drought-prone conditions. Large regions of the planet, especially the mid-latitudes, are expected to become more drought-prone by 2100.

Climate change is also altering the timing of water availability.

Case study:  California droughts

California experienced a particularly drawn-out drought from December 2011 to March 2019. And 2020 saw widespread, prolonged drought that was exacerbated by heat waves in more than a dozen Western and Central states. The intense drought and heat combined to wither vegetation, intensified Western wildfires that burned record acreage.

    • Extreme Precipitation and Climate Change:

As the planet continues to warm, warmer air can hold more water vapor. For each degree of warming, the air’s capacity for water vapor goes up by about 7 percent. An atmosphere with more moisture can produce more intense precipitation events.

Warming increases precipitation variability, meaning there will be more periods of both extreme precipitation and drought. This creates the need for expanded water storage during drought years and increased risk of flooding and dam failure during periods of extreme precipitation.


  • Shift of Hurricanespolewards:Areas affected by hurricanes are shifting pole-ward. This is associated with expanding tropics due to higher global average temperatures.
  • Warmer sea surface temperaturescould intensify tropical storm wind speeds, as more low pressures will be generated and phenomena of rapid intensification will become more common. NOAA has suggested that an increase in Category 4 and 5 hurricanes is likely, with hurricane wind speeds increasing by up to 10 percent.

For example: recent storms such as Florence in 2018 and Imelda in 2019demonstrate the devastating floods that can be triggered by these high-rain hurricanes.

  • Sea level riseis likely to make future coastal storms, including hurricanes, more damaging. Globally averaged, sea level of rise by 1-4 feet in low and moderate emissions scenarios during this century, which is expected to amplify coastal storm surge.

Example: Recently, Hurricane Ida made landfall in Louisiana, US- an extremely dangerous Category 4 storm and one of the most powerful storms ever to hit the US.

  • Wildfires and climate change:Wildfire risk depends on a number of factors, including temperature, soil moisture, and the presence of trees, shrubs, and other potential fuel. All these factors have strong direct or indirect ties to climate variability and climate change. Changes in climate create warmer, drier conditions. Increased drought, and a longer fire season are boosting these increases in wildfire risk.

For example:For much of the U.S. West, projections show that an average annual 1 degree C temperature increase would increase the median burned area per year as much as 600 percent in some types of forests.

  • Case study: The Impact of Extreme Events and Climate Change on Agricultural and Fishery Enterprises in Central Vietnam

According to the Plan for implementing the National Strategy for Prevention, Control and Mitigate the Impacts of Natural Disasters, 2020, annual losses caused by extreme weather events can occupy about 1.5% GDP, especially from agriculture because:

  • The increase of the temperature or the unusual fluctuations of the weather and climate change affect agricultural production activities even adversely.
  • The irregularities of climate cycle not only lead to an increase of diseases, pests and a decrease in crop yields, but also pose other serious risks.
  • Water quantity for irrigation has declined, even groundwater source is also seriously decreased. High temperature base leads to water shortages in dry season and threaten forest fires, especially in Gia Lai,Vietnam. Therefore, in the dry season, tens of thousands of cropping hectares such as coffee, pepper, wet rice, and short-term crops in the Central Highlands lack irrigation water seriously which badly affects the yield and productivity of agricultural enterprises.

  • Way forward:
  • Investing in resilience and disaster risk reduction, especially data gathering and analysis for evidence-informed action
  • Holistic responses and cross-sectoral collaboration are key in the disaster response. Countries must adopt a multi-hazard and multi-sectoral systemic risk management approach to anticipate, prevent, prepare for and respond to disaster risk in agriculture. Strategies need to integrate not only natural hazards, but also anthropogenic and biological threats, such as the COVID-19 pandemic, and must be based on an understanding of the systemic nature and interdependencies of risks.
  • Substantially increase the availability and access to multi-hazard early warning systems and disaster risk information and assessments to people by 2030.
  • Climate change and sustainable development are fundamentally connected: Put in place sustainable development policies and actions that reduce deprivation, alleviate poverty and ease ecosystem degradation while also lowering emissions, reducing climate change impacts and facilitating adaptation.



  • Where can we use it : Paper1(Climate change and Environmental geography) and paper 2(Contemporary, Agriculture and Resources)

GS- P1 (Geographical phenomena- climate change), P3 ( Environment).


Keywords: Geography, Optional, GS, climate change, extreme events
News in Brief

Cyclone Gulab: An exceptional Cyclone in the Bay of Bengal


  • In the 21st century, Cyclone Gulab is only the third Bay of Bengal cyclone to make landfall in September, during the active monsoon season- when temperatures across the Bay of Bengal are expected to be lower than conducive for cyclone intensification. 
  • The two other such cyclones have been Cyclone Pyarr, which made landfall in Andhra Pradesh in 2005, and Cyclonic Storm Daye, which hit Odisha in 2018. 


How can we call Cyclone Gulab as an exception in the Bay of Bengal?

Typically, tropical cyclones in the North Indian Ocean region (Bay of Bengal and  Arabian Sea) develop during the pre-monsoon (April to June) and post monsoon (October to December) periods. But on rare occasions, cyclones do occur in June and September months i.e. during active monsoon season.

Why generally cyclones do not form during active monsoon season?

  • Vertical Wind Shear:

Cyclones are less common during the June to September monsoon season, as there are limited or almost no favourable conditions for cyclogenesis due to strong monsoon currents. This is also the period when the vertical wind shear — that is, the difference in the speeds and direction of winds at different altitudes, is very high. This dampens the intensification or increase in strength and wind speeds of cyclone. As a result, clouds do not grow vertically and monsoon depressions often fail to intensify into cyclones.


  • Strong opposing winds:“Generally, the monsoon conditions are not favourable for cyclones to develop in the North Indian Ocean,” explained Roxy Mathew Koll, climate scientist at the Indian Institute of Tropical Meteorology and contributing author for the IPCC’s Sixth Assessment Report (AR6), published in August. “This is because of the strong opposing winds in this region — the lower atmospheric winds are in one direction (southwesterly) and the upper atmospheric winds are in the other direction (northeasterly). This prevents a cyclone from developing vertically.”

Then, what contributed to the formation of Cyclone Gulab?

The remnants of a cyclone (rotational element) formed in the South China Sea came to the Bay of Bengal. In the Bay of Bengal, the ocean-atmospheric conditions (mainly three factors — the in-sync phase of Madden Julian Oscillation (MJO), warm sea surface temperatures over the Bay of Bengal, and the formation of a low pressure system on September 24 along lower latitudes) were favourable for the cyclone to re-emerge again, as cyclone Gulab.

Re-emergence of cyclone Gulab into cyclone Shaheen:

Cyclone Gulab, after weakening into a depression, started gaining moisture from monsoon trough.As it reached Arabian Sea, the depression got intensified into deep depression and turned into a full-fledged cyclone called Shaheen- which wreaked havoc in Oman.


Where it can be used?

This can be used in topics related to Paper 1 (Tropical cyclones, Climate Change), Paper 2 (Tropical Cyclones, Floods) and GS1 (Important geophysical phenomena).

Tags: UPSC, Geography, Optional, Tropical Cyclones, Oceanography, Cyclone Gulab, Cyclone Shaheen, Climate Change.



Keywords: UPSC, Geography, Optional, Tropical cyclones, Oceanography, Cyclone Gulab, Cyclone Shaheen, climate change
News in Brief

Deteriorating air quality in Delhi- the menace of winter smog

Why in News? -The first severe smog episode has hit Delhi and the National Capital Region (NCR) recently.

Reasons behind high pollution levels?


  • According to a study conducted by the National Physical Laboratory 72 per cent of Delhi's wind in winters comes from the northwest, while the remaining 28 per cent comes from the Indo-Gangetic plains.
  • Winter inversion(The dip in temperatures is also behind the increased pollution levels. As temperature dips, the inversion height — which is the layer beyond which pollutants cannot disperse into the upper layer of the atmosphere — is lowered. The concentration of pollutants in the air increases when this happens), valley effect in addition to industrial emissions, vehicular emissions are some of the reasons for the increasing amount of air pollution in winter.

  • Air pollution in Delhi is blamed on crop-burning—time when farmers set fire to leftover rice stalks and straw after harvest, a practice known as stubble or paddy burning.The burning coincides with meteorological conditions that lead to temperature inversions, which trap smoke in place. 
  • Industrial Pollution Delhi has the highest cluster of small-scale industries in India. According to CPCB, the national capital is home to and surrounded by highly pollutive industrial clusters.

For example: The Najafgarh drain basin in Delhi—which includes the Anand Parbat, Naraina, Okhla and Wazirpur industrial areas—is the second most polluted cluster in India: its air are in the “critical” category in toxic content.

  • Vehicular Emissions: The transport sector is the main source of PM2.5 emissions in Delhi (28 percent of all PM2.5 emissions). Data on vehicular pollution in Delhi shows the following: trucks generate 9 percent of emissions; 7 percent from two-wheelers; 5 percent from three-wheelers; 3 percent each from cars and buses; and 1 percent from light commercial vehicles. In all, these vehicles are responsible for 41 percent of the total pollution load in Delhi

  • Construction:The outskirts of NCT have roughly 360 brick kilns, mostly in the Jhajjar, Faridabad and Ghaziabad regions. Their emissions rise during the winter months.  According to Delhi Pollution Control Committee (DPCC) officials, 30 percent of air pollution in the territory is caused by dust from construction sites.

Steps to Tackle the Problem of Pollution in Delhi:

  • Initiatives such as a 1,600 km long and 5 km wide, The Great Green Wall of Aravalli green ecological corridor along Aravalli range from Gujarat to Delhi which will also connect to Shivalik hill range is being considered with planting of 1.35 billion (135 crores) new native trees over 10 years to combat the pollution.
  • Technology - Subsidy to farmers for buying Turbo Happy Seeder (THS) which is a machine mounted on a tractor that cuts and uproots the stubble, in order to reduce stubble burning.
  • The introduction of BS-VI vehicles, push for electric vehicles (EVs), Odd-Even as an emergency measure and construction of the Eastern and Western Peripheral Expressways to reduce vehicular pollution.
  • Implementation of the Graded Response Action Plan (GRAP)
  • Development of the National Air Quality Index (AQI)for public information under the aegis of the CPCB.


  • Smog towers: around 24 m high structure uses a state-of-the-art filtration system to suck in polluted air, purify it using filters and push out clean, breathable air.

 Smogis air pollution that reduces visibility. The word “smog” is a contraction of the words smoke and fog to refer to smoky fog due to its opacity, and odor.This kind of visible air pollution is composed of nitrogen oxides, sulphur oxides, ozone, smoke and other particulates. Man-made smog is derived from coal combustion emissions, vehicular emissions, industrial emissions, forest and agricultural fires and photochemical reactions of these emissions.

  • Where can we use it

Paper1: climatology, Environmental geo (influence of man on ecology and environment, ecosystem degradation, sustainable development), Economic geo (LTG).

Paper2: Agriculture, Resources, contemporary issues (issues related to pollution).

GS: P3 (conservation, environmental pollution and degradation)


Keywords: Climatology, Environmental geo (influence of man on ecology and environment, ecosystem degradation, sustainable development), Economic geo (LTG).
Key Terms

Natural Capital

  • Why in news: Natural Capital Accounting and Valuation of the Ecosystem Services (NCAVES) India Forum-2021was organized recently by MoSPI in India.
  • The Convention on Biological Diversity (CBD) defines natural capital as the world’s stocks of natural assets which include geology, soil, air, water and all living things. It is from this Natural Capital that humans derive a wide range of services, often called ecosystem services, which make human life possible.
  • Need for Natural capital accounting: Valuing natural capital enables governments to account for nature's role in the economy and human well-being. For businesses, it enables efficiency, sustainability, and managing risks in their supply chains.
  • In June 2012 a 'natural capital declaration' (NCD)was launched at the Rio+20 summitheld in Brazil with an objective of integrating natural capital considerations into loans, equity, fixed income and insurance products, as well as in accounting, disclosure and reporting frameworks.
  • In July 2016, the Natural Capital Coalition released the Natural Capital Protocolwhich provides a standardized framework for organizations to identify, measure and value their direct and indirect impacts and dependencies on natural capital.
  • A World Bank publication, “The Changing Wealth of Nations”highlighted that the depletion of natural capital poses a significant challenge to achieving poverty reduction and sustainable development objectives.



Keywords: 1) Natural Capital
Key Terms


Rashtriya Krishi Vikas Yojana – Remunerative Approaches for Agriculture and Allied Sectors Rejuvenation (RKVY-RAFTAAR) is aimed at strengthening infrastructure in Agriculture and Allied sectors to promote Agripreneurship and Agribusiness by facilitating financial aid and nurturing a system of business incubation.

  • The main objective of Rashtriya Krishi Vikas Yojana is to develop farming as the main source of economic activity. Some of the objectives also include:
  • Risk mitigation, strengthening the efforts of the farmers along with promoting agri-business entrepreneurship through the creation of agri-infrastructure.
  • Providing all the states with autonomy and flexibility in making plans as per their local needs.
  • Helping farmers in increasing their income by encouraging productivity and promoting value chain addition linked production models.
  • To reduce the risk of farmers by focusing on increasing the income generation through mushroom cultivation, integrated farming, floriculture, etc.
  • Empowering the youth through various skill development, innovation, and agri-business models.
  • The sub-schemesincludes national priorities such
  • Bringing Green Revolution to Eastern India (BGREI),
  • Crop Diversification Program (CDP),
  • Reclamation of Problem Soil (RPS),
  • Foot & Mouth Disease – Control Program (FMD-CP),
  • Saffron Mission,
  • Accelerated Fodder Development Programme (AFDP).
  • Relevance of scheme:
  • The scheme will incentivize states to enhance more allocation to Agriculture and Allied Sectors.
  • It will strengthen farmer’s efforts through creation of agriculture infrastructure that will help in supply of quality inputs, market facilities etc.
  • It will further promote agri-entrepreneurship and support business models that will maximize returns to farmers.

Tags: Raftaar, optional, GS, agriculture, UPSC

Keywords: Raftaar, Optional, GS, agriculture, UPSC
Key Terms

Tarn lakes

A tarn (or corrie loch)may be defined as a proglacialmountainlake, formed in a cirque/corries quarried by a glacier.The word tarn comes from the Old Norse tjorn which means "small mountain lake with no tributaries."


Tarns are the outcome of glaciers called cirques/ corries. Cirques form in depressions on mountainsides near the firn line. Eventually, the depression in which a cirque forms may become a large bowl shape in the side of the mountain, caused by weathering (by ice segregation, and erosion through plucking). The basin becomes deeper as it continues to be eroded.

Tarns may either be seasonal features like the supraglacial lakes, or permanent features which form in the hollows left by cirques.Figure 1 shows the formation of Tarn Lake.


  • Both corries and tarns are typically located in higher topographies to match their glacial origins. Tarn lakes are formed in glacially carved corries.
  • They are often obstructed by moraines.

  • Tarns are usually full of tiny, glacially-ground sediment that pass the light and make the water color.
  • Some famous examples of tarn are: Lake Tear of the Clouds,Adirondack Mountains, and New York.