Causes of social change

Environment. Nature has always shaped society: people in deserts could not farm as people in river plains could, and their food, clothes, livelihoods and ways of interacting differed. With technology, nature's influence is changing rather than simply declining.

• Natural disasters can change societies drastically and often irreversibly: after the December 2004 tsunami, which struck Indonesia, Sri Lanka, the Andaman Islands and parts of Tamil Nadu, many people could never return to their old livelihoods, and coastal villages were transformed.
• The environment can also cause constructive change: the discovery of oil in the deserts of West Asia transformed countries like Saudi Arabia, Kuwait and the UAE, as gold did California in the 19th century.

Technology and economy. Together they have caused immense change, especially in the modern period.

• Steam power gave industry a source of energy far stronger than humans or animals, able to work without rest. Harnessed to steamships and railways, it changed the world's economy and social geography. In India, railways were introduced in 1853 and shaped the economy in the following century.
• Some inventions show their impact only later: gunpowder and writing paper from China had limited effect for centuries, until modernising Western Europe used them to transform warfare and printing.
• Closer to home, the book traces how Britain's new textile machines affected India's handloom industry, until then the largest and most advanced in the world.
• Changes in economic organisation matter too: plantation agriculture (sugarcane, tea, cotton) needed huge amounts of labour, which helped establish slavery and the slave trade between Africa, Europe and the Americas; in India, the Assam tea plantations involved the forced migration of labour from Adivasi areas of Jharkhand and Chhattisgarh. Today, changes in tariffs through bodies like the WTO can wipe out whole industries or bring sudden booms.

Politics. Kings and queens were really representatives of larger forces. War brings change: after defeating Japan in the Second World War (partly with the nuclear bomb), the USA occupied Japan and brought land reform; by the 1970s, Japanese industry (cars, electronics) had overtaken America's and forced US industry to restructure. Change at home matters too: India's independence movement changed Indian society, and Nepal rejected monarchy in 2006.

• Universal adult franchise, 'one person, one vote', is probably the single biggest political change in history. At first only wealthy men or men of high-status groups could vote; women, the poor and many others won the vote only after long struggles. Though inequalities remain, every government must now at least appear to seek the people's approval.

Culture (ideas, values and beliefs):

• Religion: Max Weber's The Protestant Ethic and the Spirit of Capitalism showed how beliefs of some Protestant sects helped establish capitalism. In India, Buddhism shaped ancient social and political life, and the Bhakti movement influenced medieval social structure, including caste.
• Women's struggles for equality: during the Second World War, women in Western countries built ships and ran heavy machinery, strengthening their claim to equality. Women's role as household decision-makers also changed advertising, which now often addresses women and shows them as decision-makers.
• Sport: cricket began as a British aristocratic pastime, spread to the colonies, and became a symbol of national or racial pride: Australia's rivalry with England, the West Indies' dominance in the 1970s and 1980s, and India's joy at beating England. Today South Asian, especially Indian, fans drive the game's commerce.

No single factor explains social change. Causes may be internal or external, deliberate or accidental, and they are often interrelated: economic change may have a cultural side, politics may be shaped by environment.

Example (new): cheap smartphones and internet data (technology and economy) let a village girl attend online classes (culture: changing ideas about girls' education), helped by a government scheme (politics): several causes working together.