Climate disasters and climate change

When weather turns extreme

India’s varied weather can bring extreme events: cyclones, floods, landslides and other climate-related disasters. They take lives, disrupt farming, damage roads, bridges and buildings, and upset local economies. Knowing how and where they strike helps us prepare.

Cyclones

Every year several cyclones hit the Indian coast, especially the eastern coast. Some have been highly destructive: they killed people and animals, damaged property and infrastructure, uprooted trees and washed away soil. A cyclone begins when the air pressure over the sea drops well below that of the surrounding areas. Air flows into this low-pressure area from all around, bringing moisture from the sea. If the low is intense and the winds are fast, a cyclone forms: the moist winds build clouds and swirl inwards around a calm, cloudless centre, the eye of the cyclone. The India Meteorological Department (IMD) tracks cyclones, from how they form and grow to where they will reach land. The National Disaster Response Force (NDRF), with battalions at 12 places in India, is trained to rescue and evacuate people in cyclones, floods and landslides.

Floods

A flood happens when water spills onto land that is normally dry. Heavy rain may produce more run-off than the land can absorb, or rivers and lakes may fill until they overflow or burst their banks. Floods are frequent in the monsoon, and Assam, Bihar, Uttar Pradesh, Kerala and Andhra Pradesh face them most. In the Himalayas, floods also come from glacial lakes, held back by walls of rock and ice and fed by melting glaciers. When glaciers melt faster than usual, which happens more and more often, or when heavy rain falls, the water can smash through that wall: a glacial burst. In 2013 a glacial burst in Uttarakhand, set off by days of heavy rain, was followed by landslides; the area around the Kedarnath temple was destroyed and some 6,000 people died, many of whom were pilgrims. Cities flood too, when drains are overburdened, buildings block waterways, and concrete and asphalt stop water soaking into the ground.

Landslides

In a landslide, rock, soil or debris suddenly gives way and falls down a slope, usually set off by heavy rain, an earthquake or volcanic activity. They happen often in the mountain states of Uttarakhand, Himachal Pradesh, Arunachal Pradesh and Sikkim, and in the Western Ghats, mostly during the monsoon. Human activities have made them more likely: cutting down forests, building without approved methods, and putting up so many buildings that they block the natural flow of water.

Forest fires

A forest fire is a fire out of control that races through trees, grass and bushes, helped along by dry weather, droughts or strong winds; human carelessness often starts one. They break out often in states with large forests or grasslands, such as Madhya Pradesh, Chhattisgarh, Uttarakhand and Himachal Pradesh, and in mountain ranges such as the Western Ghats. Fires destroy forests, harm wildlife, damage the ecosystem, pollute the air and force local communities to move, so their cost is both environmental and economic.

Climate change

Climate change means significant, long-term changes in the climate, of the whole planet or of a region: shifts in temperature, rainfall and weather events. Over millions of years natural processes drove such changes. From the 19th century onwards, though, human activities have been the main driver: burning fossil fuels (coal, petroleum and natural gas, formed from plants and animals buried millions of years ago), cutting forests, harmful industrial practices and wasteful consumption.

Why do fossil fuels matter? Carbon dioxide and some other gases are a normal part of the Earth’s carbon cycle; released slowly, they hold back some of the Sun’s heat. This natural greenhouse effect keeps the Earth warm enough for life. But industry, transport and farming have poured out these greenhouse gases in huge quantities within only a few hundred years. The extra gases trap extra heat, causing rapid global warming and upsetting climate patterns that plants, animals and people adapted to over thousands of years.

Warming in India, and what we can do

Rising temperatures are already felt in many parts of India. Early in 2025, temperatures across India were 1 to 3°C higher than usual, giving a far shorter, gentler winter than normal, which affected farm output and many small-scale industries. Understanding how climate change and disasters are linked helps us prepare: through environment-friendly practices, and by building resilience, the ability to bear a shock and recover quickly, and adaptation in communities. Governments, including India’s, promote mitigation: planting trees, cutting the emissions of greenhouse gases, using more renewable energy, using energy more efficiently and encouraging sustainable lifestyles, ones that can be kept up for a long time. These steps often clash with the wish for faster economic growth and more consumption.

Why it matters

Disasters and a warming climate affect everyone, and good choices by individuals, communities and governments reduce the harm. How India’s climates come about is explained in factors that shape climate, and the rains that can bring floods in the monsoons. Answers to every question, including the disaster essay, are in the NCERT solutions for Chapter 3; see all of the Chapter 3 notes.