Section 4.3.2Unit 4: Developments in the Global Economy
Unit 4: Developments in the Global Economy
Trade and the Global Economy
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A country has a comparative advantage when it can produce a good at a lower opportunity cost than another — and both countries gain from trade if terms of trade fall between their opportunity cost ratios.
Comparative advantage is the foundation of the economic case for free trade. A country has a comparative advantage in a good if it can produce that good at a lower opportunity cost than another country. Crucially, even a country that is less efficient at producing everything (absolute disadvantage in all goods) still benefits from trade by specialising in its least-worst product.
The logic is precise. Calculate the opportunity cost of each good in each country. Each country should specialise in the good where its opportunity cost is lower. If the terms of trade (the exchange ratio) fall between the two countries' opportunity cost ratios, both countries can consume beyond their production possibility frontier. Trade is not zero-sum — it expands the total pie.
The model rests on assumptions: constant costs, perfect factor mobility within countries, zero transport costs, and no trade barriers. In reality, these rarely hold — but the core insight remains powerful. Countries that trade according to comparative advantage achieve higher output and consumption than those that try to produce everything domestically.
Real Example: Bangladesh has a comparative advantage in textiles due to low labour costs, while Germany has a comparative advantage in precision machinery due to its skilled workforce and capital stock. Both gain when Bangladesh exports garments and imports German engineering — each focusing on what it does relatively best.
Exam Matters: Examiners frequently set numerical questions asking you to identify comparative advantage from a table. Practise: calculate opportunity costs for both goods in both countries, identify who has the lower OC in each good, then state the range of mutually beneficial terms of trade.
Free trade delivers allocative efficiency, lower prices, economies of scale, and dynamic gains from competition — though real-world frictions like immobility and exchange rate distortions limit these benefits.
Free trade generates several categories of benefit. Allocative efficiency improves because resources flow to where they are most productive globally — countries specialise according to comparative advantage. Consumer prices fall as competition from imports forces domestic firms to cut costs. Economies of scale become achievable when firms can sell to global markets rather than just domestic ones.
The dynamic gains may matter even more than the static ones. Exposure to international competition drives innovation — firms that cannot compete with imports must improve or exit. Access to foreign technology and ideas accelerates productivity growth. Over time, these dynamic effects compound, raising the economy's long-run growth rate.
However, the textbook gains assume frictionless adjustment. In practice, factor immobility means workers displaced by imports cannot easily retrain or relocate. Transport costs reduce the gains, especially for heavy or perishable goods. Exchange rate distortions — such as a currency held artificially low — can undermine comparative advantage and create unfair competition.
Real Example: The EU single market removed trade barriers between member states and intra-EU trade grew by an estimated 60%. Firms like Airbus could spread development costs across a continent-wide market, achieving economies of scale that would be impossible in any single European country.
Exam Matters: A strong evaluation distinguishes static gains (allocative efficiency, lower prices) from dynamic gains (innovation, productivity growth). Examiners reward answers that acknowledge the theoretical case is strong but identify real-world frictions that limit the gains — particularly factor immobility and structural unemployment.
Tariffs, quotas, subsidies, and non-tariff barriers all restrict imports — each raises domestic prices and creates deadweight loss, though governments argue they protect jobs, infant industries, and national security.
Protectionism means government intervention to restrict imports and shield domestic producers from foreign competition. The main tools are: tariffs (taxes on imports that raise the price to consumers), quotas (physical limits on the quantity of imports), subsidies to domestic producers (lowering their costs to compete with imports), and non-tariff barriers (NTBs) such as excessive regulation, bureaucratic customs procedures, or discriminatory standards.
The arguments for protectionism include: protecting infant industries that need time to achieve economies of scale, safeguarding national security in strategic sectors like defence and food, preventing dumping (selling below cost to destroy competitors), and protecting jobs in politically sensitive regions. Each argument has some theoretical validity but is routinely abused to protect inefficient firms with political connections.
The arguments against are powerful: protectionism raises prices for consumers, creates deadweight loss, reduces competitive pressure (so firms become less efficient over time), and invites retaliation from trading partners. History shows that trade wars escalate — the Smoot-Hawley tariffs of 1930 deepened the Great Depression by collapsing world trade.
Real Example: The US-China tariff war of 2018-2020 saw the US impose tariffs on over $360 billion of Chinese goods. China retaliated with tariffs on US agriculture. Studies showed American consumers bore most of the cost through higher prices, while US farmers lost export markets — illustrating the costs of protectionism and retaliation.
Exam Matters: Examiners love tariff diagrams. You must be able to draw one showing: world price, tariff-inclusive price, domestic production expanding, imports contracting, consumer surplus lost, producer surplus gained, government revenue, and deadweight loss triangles. Practise until this is automatic.
The WTO promotes free trade through the most-favoured-nation principle and dispute resolution, but the Doha Round's failure has shifted momentum toward bilateral and regional deals.
The World Trade Organisation (WTO), established in 1995, provides the rules-based framework for international trade. Its core principles are: most-favoured-nation (MFN) — any tariff concession given to one member must be extended to all; national treatment — imported goods must be treated no less favourably than domestic ones once inside the border; and reciprocity — trade concessions should be mutual.
The WTO's dispute settlement mechanism is often called the 'jewel in the crown' of the trading system. It provides a binding legal process for resolving trade disputes, preventing countries from unilaterally imposing protectionist measures without consequence. Over 600 disputes have been brought since 1995.
However, the WTO faces serious challenges. The Doha Development Round, launched in 2001 to address developing countries' concerns, has effectively stalled due to disagreements between rich and poor nations over agriculture subsidies and market access. The rise of bilateral and regional trade deals — such as the CPTPP and RCEP — threatens to fragment the multilateral system. Critics argue the WTO is too slow and too consensus-dependent to handle modern trade challenges like digital trade and climate-related border measures.
Real Example: The 16-year WTO dispute between the EU and US over subsidies to Airbus and Boeing is a landmark case. Both sides were found to have provided illegal subsidies, and retaliatory tariffs were authorised. It demonstrated the WTO's power to adjudicate but also its limitations — the dispute took so long that billions in distortionary subsidies were paid before any resolution.
Exam Matters: A common question asks you to evaluate the effectiveness of the WTO. Structure: successes (MFN principle, dispute resolution, reduced average tariffs) vs failures (Doha stalled, slow decision-making, rise of bilateralism). Conclude with a judgement: the WTO remains essential but needs reform to stay relevant.
A country has a comparative advantage when it can produce a good at a lower opportunity cost than another — and both countries gain from trade if terms of trade fall between their opportunity cost ratios.
Free trade delivers allocative efficiency, lower prices, economies of scale, and dynamic gains from competition — though real-world frictions like immobility and exchange rate distortions limit these benefits.