The Global Development Gap: Causes and Uneven Growth

The global development gap is the large difference in income, health, education and living standards between richer and poorer countries, and it has been caused by a mix of historical, geographical, economic and political factors, so that growth has been uneven between and within regions. In brief: causes include colonial history, trade dependence on low-value primary products, debt, conflict and weak governance, poor health and education, difficult physical geography such as being landlocked, and unfair trade rules. The gap has narrowed in some respects, since countries such as China and India have grown rapidly and extreme poverty has fallen, but many low-income countries remain far behind.

Explaining why some countries are rich and others poor is among the most debated questions in geography and economics. This guide explains how the gap is described, the main causes, the main theories, why growth is uneven, compares the causes in a table, works through calculations of growth and catching up, outlines the history and corrects common mistakes.

How big is the development gap?

Average income in the richest countries is many times that in the poorest: differences of 30 to 50 times in GNI per capita are common between the highest- and lowest-income countries. Life expectancy differs by 20 years or more, and in the poorest countries, child mortality and malnutrition are many times higher. Traditionally, geographers spoke of a divide between the “Global North” and “Global South,” represented by the Brandt Line, drawn in 1980, but the picture is more complex today, with newly industrialized countries, oil exporters and emerging economies in between. There are large inequalities within countries too, between urban and rural areas and between regions.

What are the causes of the gap?

• Colonial history: colonial rulers often extracted resources and built transport links to ports, not to serve local industry, drew borders that ignored ethnic groups and left weak institutions. Slavery and exploitation also had lasting effects.
• Physical geography: being landlocked, remote or in dry or tropical zones with disease such as malaria can increase costs and reduce productivity. Natural hazards such as droughts, floods and earthquakes cause repeated setbacks.
• Economic structure and trade: dependence on a few primary exports, such as coffee, cocoa or copper, whose prices fluctuate and tend to grow more slowly than those of manufactured goods, leaves countries vulnerable. Trade barriers in richer countries, such as tariffs and subsidies on farm products, make it harder for poorer countries to compete.
• Debt: large debts to foreign lenders mean that a large part of government income goes on interest payments instead of schools and hospitals.
• Governance and conflict: corruption, weak institutions, instability and civil wars destroy investment, infrastructure and lives.
• Health, education and population: diseases such as HIV and malaria reduce the workforce, low education limits skills, and high birth rates can strain services in the short run.
• Lack of capital and technology: low savings and investment, and limited access to modern technology, keep productivity low, and skilled workers may leave (brain drain).

What theories explain the gap?

Rostow’s modernization model (1960) proposed that all countries pass through five stages: traditional society, preconditions for take-off, take-off, drive to maturity and an age of high mass consumption. It assumes that poorer countries can follow the path of richer ones. Dependency theory, associated with Andre Gunder Frank, argues that the “core” countries keep developing at the expense of the “periphery”, which is locked into supplying raw materials. World systems theory (Immanuel Wallerstein) adds a semi-periphery. Cumulative causation (Gunnar Myrdal) suggests that regions with an early advantage attract more investment and skilled people, while others fall behind. Newer views stress the role of institutions, such as property rights and rule of law, and of integration into global trade and technology.

Why is growth uneven?

Growth is uneven because the factors above differ from place to place, and success tends to build on itself. East Asian economies such as South Korea, Taiwan and, later, China grew very fast through investment in education, manufacturing for export and supportive government policy. Many countries in Sub-Saharan Africa grew more slowly because of conflict, narrow export bases and limited infrastructure, although several have grown quickly in recent years. Global poverty fell: according to World Bank estimates, the share of the world’s population in extreme poverty fell from around 38% in 1990 to below 10% by 2019, largely because of Asian growth, but progress was slowed by the Covid-19 pandemic. Within countries, cities and coastal regions often grow faster than interior and rural regions.

Causes compared

Worked example: growth and catching up

The values are hypothetical and illustrate how growth rates change the gap.

1. Size of the gap: a rich country has a GNI per capita of 40,000 and a poor country has 2,000. The ratio is 40,000 ÷ 2,000 = 20 times.
2. Different growth rates: the rich country grows by 2% a year and the poor country by 6%. After 30 years, the rich country has 40,000 × 1.02³⁰ = about 72,500, and the poor country has 2,000 × 1.06³⁰ = about 11,500.
3. The gap in absolute terms: after 30 years, the ratio is 72,500 ÷ 11,500 = 6.3, much smaller than 20, but the absolute difference has risen from 38,000 to 61,000. A faster percentage growth can come with a larger absolute gap.
4. Catching up: the poor country catches up when 2,000 × 1.06ⁿ = 40,000 × 1.02ⁿ, so (1.06 ÷ 1.02)ⁿ = 20, and n = ln 20 ÷ ln 1.0392 = 2.996 ÷ 0.0385 = about 78 years.
5. Doubling time: at 6% growth, the income doubles in about 70 ÷ 6 = 11.7 years. At 1% growth, it takes about 70 years.
6. Debt burden: a country earns 3 billion from exports and pays 900 million a year to service its debt. The debt service ratio is 0.9 ÷ 3 = 30% of export earnings.

How has the gap developed?

Before the Industrial Revolution, differences in income between regions were relatively modest. From about 1800, industrialization in Europe and North America produced a rapid divergence, and colonial empires shaped trade and political control. After decolonization, from the 1940s to 1970s, many new states faced weak economies and the Cold War rivalry. The 1980s brought a debt crisis in Latin America and Africa, and structural adjustment programs by the IMF and World Bank, which are debated. From the 1990s, rapid growth in China and India reduced global inequality between countries, even though inequality within many countries rose. The Millennium and Sustainable Development Goals now set international targets to reduce poverty and inequality.

Which mistakes are common?

Mistake 1: Looking for one single cause

The gap results from many linked causes, such as history, geography, institutions, trade and policy.

Mistake 2: Assuming that all poor countries are alike

Some are landlocked, some are rich in minerals, some are in conflict, and some are growing quickly. Conditions and solutions differ.

Mistake 3: Confusing faster growth with a smaller absolute gap

A poor country can grow faster in percentage terms while the dollar difference with rich countries keeps growing.

Mistake 4: Treating the North-South divide as fixed

Many countries have changed their position, so the categories “developed” and “developing” are a simplification.