Maarg Manthan · Topic 18.15

Observed Climate and Weather Changes in India

Environment & Ecology › International Environmental Governance and Conventions · Topic 18.15

Observations show that India's climate is changing. The Ministry of Earth Sciences report Assessment of Climate Change over the Indian Region (2020), prepared by the Centre for Climate Change Research at IITM Pune, found that India's average temperature rose by about 0.7 degrees Celsius between 1901 and 2018, mainly due to greenhouse gases, and that the frequency of hot days and hot nights rose while that of cold days and nights fell. Summer heat waves have become more frequent, longer and more intense in recent decades. All-India summer monsoon rainfall declined by about 6 percent from 1951 to 2015, with a decline over the Indo-Gangetic plains and the Western Ghats, but heavy rain events have increased, with a threefold rise in widespread extreme rain events over central India between 1950 and 2015. The frequency and area of droughts have increased, with about two droughts per decade in recent years. Sea level in the north Indian Ocean has risen at about 3.3 mm per year in 1993 to 2017; the Hindu Kush Himalaya warmed by about 1.3 degrees between 1951 and 2014, and glaciers are retreating. Total tropical cyclones in the north Indian Ocean decreased slightly, but the frequency of very severe cyclones over the Arabian Sea has increased. The India Meteorological Department publishes annual statements on the climate of India.

5 min read · UPSC Prelims · Environment & Ecology · International Environmental Governance and Conventions

At a Glance

Warming About 0.7 C, 1901-2018
Monsoon Down about 6 percent, 1951-2015
Extreme rain Widespread events up threefold
Sea level About 3.3 mm a year
Report MoES, 2020
Exam link UPSC Prelims, Environment & Ecology: International Environmental Governance and Conventions

Where Does It Fit?

This topic follows India’s position and sets out the evidence of climate change in India. It leads to the National Action Plan on Climate Change and India’s climate assessment. Previous topic: India’s Position on Climate Change Policy. Next topic: National Action Plan on Climate Change (NAPCC) and India’s Climate Change Assessment.

What Are the Observed Changes in India’s Climate?

Indicator	Observed trend
Temperature	All-India average temperature up about 0.7 C between 1901 and 2018
Hot days and nights	More frequent hot days and warm nights, fewer cold days and nights
Heat waves	More frequent, longer and stronger in recent decades
Monsoon rainfall	All-India summer monsoon rainfall down about 6 percent from 1951 to 2015; decline over Indo-Gangetic plains and Western Ghats
Extreme rainfall	Widespread extreme rain events up about three times over central India from 1950 to 2015
Droughts	Frequency and area affected up; about two droughts per decade in recent decades
Sea level	North Indian Ocean rose about 3.3 mm a year in 1993 to 2017

What About Cyclones, Glaciers and Projections?

Cyclones: fewer total cyclones but more very severe ones over the Arabian Sea
Himalaya: Hindu Kush Himalaya warmed about 1.3 C between 1951 and 2014
Glaciers: most Himalayan glaciers are retreating, affecting river flow
Snow cover: declining over the Himalaya
Projections: temperatures expected to rise by about 4.4 C by 2100 under a high emissions scenario
Heat waves ahead: three to four times more frequent by 2100 under high emissions
Monsoon ahead: rainfall likely to increase overall with more intense downpours
Sea level ahead: could rise 300 mm by 2100 and more

What Else Should You Remember?

Assessment of Climate Change over the Indian Region: released in June 2020, the first national assessment, led by R Krishnan
CCCR-IITM: Centre for Climate Change Research, Indian Institute of Tropical Meteorology
0.7 C warming: rise in average temperature from 1901 to 2018
Warm nights: have increased faster than hot days
Lows and highs: minimum temperatures rose faster than maximum
Hot days: days above 95th percentile have risen
Wet days: decline in total rainy days but more intense rainfall
Monsoon decline: partly linked to human aerosol emissions and warming of the Indian Ocean
Indian Ocean warming: sea surface temperature up by about 1 C in 1951 to 2015
Marine heat waves: increasing frequency in the Indian Ocean
Floods: flash floods in Kerala (2018), Chennai (2015), Uttarakhand (2013 and 2021) and Himachal (2023)
Glacial lake outburst: Sikkim’s South Lhonak lake burst in 2023
Cyclones: Amphan (2020), Tauktae (2021), Biparjoy (2023), Remal and others
Heat waves recorded: deadly heat waves in 2010 and 2015 in Ahmedabad, Andhra Pradesh and Telangana
2022 spring: record March heat in northwest India and 2024 heat waves
IMD: India Meteorological Department publishes annual climate statements
India State of Climate: reports by IMD and the Ministry
Warmest years: India’s recent years like 2016, 2022 and 2024 have been among the warmest on record
Agriculture impact: wheat yield hit by March heat in 2022
Coastal impact: erosion and sea level rise in Sundarbans and Odisha coast
Link to previous: see India’s Position on Climate Change Policy
Link to next: see National Action Plan on Climate Change (NAPCC) and India’s Climate Change Assessment
Link to impacts: see Impacts of Climate Change: Acid Rain, El Nino, La Nina, Ozone Depletion, Ocean Acidification
Caution: numbers come from the 2020 assessment and are updated by IMD, so check the latest data
Exam hint: remember 0.7 C, 6 percent monsoon decline, threefold extreme events and the 2020 report

Why Does It Matter for the Exam?

Warming: 0.7 C
Monsoon trend: Down about 6 percent
Extreme rain: Up three times
Current affairs link: IMD annual climate statements
Common errors: claiming total monsoon rainfall has risen

As an analytical point, India’s climate is warming with more extreme heat and rain even as total monsoon rainfall slips. This combination means longer dry spells and sudden floods, a sharp challenge for farming and cities.

Why Is This Topic Important?

Heat Rising
Rain Extremes up
Sea Rising

What Came Next?

The next topic covers the National Action Plan on Climate Change and India’s climate change assessment. Next topic: National Action Plan on Climate Change (NAPCC) and India’s Climate Change Assessment.

Key People and Terms

CCCR Centre for Climate Change Research
IITM Institute of Tropical Meteorology
IMD India Meteorological Department
GLOF Glacial lake outburst flood
Warm night Night with high minimum temperature
Hindu Kush Himalaya Himalayan region

Exam Corner

Points to Remember

Warming 0.7 C in 1901-2018.
Monsoon down about 6 percent.
Extreme rain events up three times.
Sea level up 3.3 mm a year.
Report from MoES, 2020.

Do Not Confuse With

Total rainfall and extreme rainfall Declining versus rising
Maximum and minimum temperature Day highs versus night lows
Hot days and heat waves Single hot days versus spells

Memory Hook

Point seven warmer, six percent less monsoon, thrice the extreme downpours.

Mains Angle

Questions ask for trends with numbers. These points help.

Trends Heat, rain, sea
Himalaya Warming
Impacts Farm, cities

A Question You May Face

An original practice question, not a past paper question.

“Describe the observed changes in India’s climate and their significance, with reference to the national climate assessment.”

How to Answer

Report 2020.
Heat 0.7 C.
Rain Monsoon, extremes.
Sea Rise.

GS Relevance

Prelims: findings of the 2020 assessment. GS Paper 1 and 3: observed climate change in India.

Frequently Asked Questions

How much has India warmed?

According to the Ministry of Earth Sciences' 2020 Assessment of Climate Change over the Indian Region, India's average temperature rose by about 0.7 degrees Celsius between 1901 and 2018. Warming is higher in the Hindu Kush Himalaya, where temperature rose by about 1.3 degrees between 1951 and 2014, and recent years have been among the warmest on record.

How has the Indian monsoon changed?

All-India summer monsoon rainfall declined by about 6 percent from 1951 to 2015, with notable decreases over the Indo-Gangetic plains and the Western Ghats. At the same time, the number of extreme rain events has increased, with widespread extreme events over central India up about threefold from 1950 to 2015, so rainfall has become more erratic.

What is the trend in heat waves in India?

Heat waves have become more frequent, longer and more intense in recent decades, with deadly episodes in 2010, 2015 and in the spring of 2022 and 2024. Hot days and nights have increased and cold days have decreased. Projections show that heat waves could become three to four times more frequent by 2100 under high emissions.

How much has sea level risen in the north Indian Ocean?

Sea level in the north Indian Ocean has risen by about 3.3 millimetres a year between 1993 and 2017, similar to the global average, according to the assessment. Projections suggest a rise of about 300 millimetres by 2100 relative to 1986 to 2005 under a moderate scenario, with more in high emissions, threatening coastal cities and deltas.

What is the trend in cyclones over India?

The total number of tropical cyclones over the north Indian Ocean has decreased slightly, but the frequency of very severe cyclones over the Arabian Sea has increased in recent decades, linked to a warming sea surface. Cyclones like Tauktae in 2021 and Biparjoy in 2023 were examples, and coastal states have invested in early warning and shelters.

PYQ Practice — Statement Analysis

1 India's average temperature rose about 0.7 C from 1901 to 2018.

True

As per the 2020 assessment.

2 Monsoon rainfall in India has risen sharply since 1950.

False

It declined about 6 percent.

3 Extreme rain events in central India have increased.