London — Travel and tourism is one of the world’s largest and fastest-growing industries, and the number of leisure travellers globally is set to increase enormously in the next few decades as more families reach middle-class status.

Travel to learn more about the world and experience new places appears to be a basic human instinct; all modern societies show increasing demand for travel, much of it for leisure, as incomes rise and transportation improves.

Leisure travel is set to make one of the largest contributions to rising energy consumption and carbon emissions through 2050, with much of the increase concentrated in Asia, the Middle East, Africa and Latin America.

International air travel will make an especially large contribution to emissions because aviation is energy-intensive and for the foreseeable future there are no low-carbon alternatives to relying on jet fuel.

Pre-modern societies

Before the modern era, leisure journeys, or indeed any travel, were difficult, expensive and rare for most of the population.

Governments discouraged casual travel because of the potential threat to social and political stability; travellers were almost universally viewed with suspicion.

In Britain before about 1700, almost the only long-distance travellers on the roads were aristocrats, soldiers, judges, priests and tax collectors, together with a small number of sailors plying coastal sea routes.

The law banned non-essential trips. Anyone found outside their home parish without a lawful reason could be punished for vagrancy by whipping and forced to return.

Similar restrictions on casual movement were introduced in most other European and Asian countries to maintain political control and economic stability.

“Most of the population travelled little, rarely seeing neighbouring villages, let alone the nearest market town,” writes Roger Fouquet, author of Heat, Power and Light: Revolutions in energy services.

But the improvement of transportation during the 18th and 19th centuries, with heavy investment first in roads and later on canals and railways, unleashed a tremendous increase in personal mobility.

Some of that increased travel was work-related, as economies became more integrated, with local markets and industries gradually replaced by regional and then national markets.

But much of the surge in journeys by road and later rail was more discretionary and reflected rising incomes and the greater opportunities to travel created by more advanced technology.

Mobility revolution

The introduction of turnpike trusts — charging tolls to build and maintain highways — on major routes led to an improvement in the quality of Britain’s roads from the middle of the 18th century.

The result was a rapid and sustained increase in long-distance inter-city travel for freight but more especially for passengers.

Inter-city coaching services became more frequent and faster, with the number of passenger services to and from London quadrupling from 1760-1780 and then doubling again by 1790.

Passenger services increased much faster than freight, at least in the first few decades, an indication of the pent-up desire to travel that was released once transport became easier and cheaper.

The same pattern was repeated a century later with the advent of the railways, which quickly replaced horse-drawn carriages as the dominant mode of passenger transport for journeys of more than a few miles.

Growth in rail traffic was led by passengers rather than freight, most of them drawn from low-income groups that had not previously travelled much.

“Contrary to the original expectation, the opening of Britain’s early railways had a more immediate impact on the pattern of passenger travel than it did on goods traffic,” according to historian Philip Bagwell, author of The Transport Revolution from 1770.

“With very few exceptions, whenever a new line was opened to traffic there was a spectacular increase in the number of persons travelling along the route served compared with the numbers previously using the road.

“After the opening of the Newcastle and Carlisle Railway ... eleven times as many persons travelled by train as had previously gone by coach.”

Passenger rail journeys increased from 5-million in 1838 to 100-million in 1854, 500-million in 1876 and 1-billion in 1897, a 200-fold increase in 60 years.

Rising incomes and improvements in the transport system unleashed a revolutionary increase in personal mobility in Britain between 1750 and 1900.

In the 20th and 21st centuries, the mobility revolution continued with the introduction of the motor car and then international air travel.

The number of passenger-miles flown surged from 3-million in 1925 to 50-million in 1937, 500-million in 1948, 1-billion in 1951, 10-billion in 1969 and 31-billion in 1980.

International travel is still increasing. UK travellers made almost 72-million visits overseas in 2018, up from 51-million in 1998 and 29-million in 1988.

China travel boom

Britain’s mobility revolution has been matched or exceeded in all the advanced economies of Europe, North America, Japan and Australasia.

Now the mobility revolution is spreading to China and other rapidly developing economies in Asia and around the world as hundreds of millions more people move out of poverty and the middle class expands.

China’s railway passenger traffic has been growing at a compound average annual rate of more than 6% since 1990 while air travel has been soaring at almost 15% a year.

China’s passenger rail traffic has been doubling every 12 years while air passenger traffic has been doubling every five years, according to government data.

Huge investment in rail networks, including long-distance high-speed systems, as well as airports and aircraft has boosted capacity, reduced travel times and encouraged a surge in internal travel, much of it leisure-related.

China’s rail network had grown to 127,000km in 2017, up from 78,000km in 2007 and 66,000km in 1997, according to the National Bureau of Statistics.

The high-speed rail network has grown from less than 1,000km in 2008 to more than 25,000km by 2017.

Air routes have more than quadrupled since the turn of the century while the number of aircraft in use has risen five-fold.

Growth in overseas travel by China’s middle class is also soaring. China’s residents made 143-million trips overseas in 2017, up from 41-million in 2007 and 5-million in 1997, according to the World Tourism Organization.

After China

China’s mobility revolution is far from completed. And behind China are other nations in Asia, Africa and the Middle East where the revolution has barely begun.

India’s residents made just 26-million trips overseas in 2018 compared with 70-million in the UK and 93-million in the US.

Internal travel across most developing economies is still held back by lack of quality roads, limited rail capacity and affordability.

But internal and external travel is starting to grow as incomes rise and transport systems slowly improve, and the trend is set to accelerate in the next several decades.

Rising transport demand for leisure as well as business travel and freight poses a tremendous challenge for both energy and climate policy.

Policymakers have to find a way to decarbonise the energy system and curb emissions while accommodating enormous growth in demand for travel as well as other services such as air-conditioning.

The global travel revolution underscores how challenging it will be to meet emissions targets while satisfying growing aspirations for tourism and leisure.