9.2 Economic growth and sustainability

Actual economic growth is a rise in current real output. Potential growth is a rise in productive capacity or the sustainable level of output.

Actual growth can occur when firms use spare capacity and may reverse in a downturn. Potential growth usually requires more resources, better productivity or technology and can support higher output without the same inflation pressure.

A factory reopening idle machines creates actual growth toward capacity; new automation that raises the maximum sustainable output creates potential growth.

A temporary demand boom is not automatically long-run growth, and potential growth does not guarantee actual output rises if demand is weak.

The output gap is the difference between actual real GDP and estimated potential GDP, often expressed as a percentage of potential. A negative gap indicates spare capacity; a positive gap indicates output above sustainable capacity.

Potential output is not directly observed, so the gap is an estimate and can be revised. A negative gap often accompanies unemployment and weak inflation pressure; a positive gap may accompany bottlenecks and demand-pull inflation.

If actual GDP is 980 and potential GDP is 1,000, the output gap is −2% of potential. The number is not a precise count of unemployed people.

An output gap is not simply the GDP growth rate, and a zero estimated gap does not prove every resource is fully employed.

The business cycle is the pattern of expansions and contractions in economic activity around a longer-run trend. Phases may include recovery, expansion, peak, slowdown and recession, but the labels are conventions.

Demand, financial conditions, confidence, inventories, external shocks and policy can amplify cycles. A recession is a period of falling or unusually weak activity; it is not defined solely by one fixed rule in every context.

A credit boom raises spending and employment, then a financial shock cuts investment and demand, creating a downturn below the trend path.

The cycle is not perfectly regular or predictable, and a short slowdown need not meet every definition of recession.

Policies for growth include expansionary fiscal or monetary policy to raise actual output in the short run, and supply-side measures to raise potential output in the long run.

The best mix depends on the output gap, inflation, debt, external balance and the binding constraint. Public investment can affect both AD and LRAS; education takes time but may improve productivity.

During a deep recession, infrastructure spending can use idle labour now and expand transport capacity later. Near full capacity, the same spending may mainly raise prices unless supply expands.

No policy creates costless growth: evaluate financing, implementation lags, distribution, environmental effects and whether demand or capacity is the constraint.

Inclusive growth is growth that improves opportunities and living standards broadly, especially for groups or regions otherwise excluded from productive participation.

It can involve access to education, health, finance, infrastructure, decent work and anti-discrimination, not just redistribution after growth occurs. Measure both aggregate output and who gains, over what time horizon.

A transport link plus vocational training can connect a neglected region to jobs and markets; a national GDP increase concentrated in one city is growth but not necessarily inclusive.

Inclusive does not mean every person receives the same income, and a transfer alone may not remove the structural barrier causing exclusion.

Sustainable economic growth increases current welfare while preserving the environmental, social and physical resources needed by future generations.

Growth can be more sustainable when productivity, clean technology, resource efficiency and institutions reduce emissions and depletion. A single GDP measure does not capture external costs, resilience or distribution.

Investment in renewable power and energy efficiency may raise current demand and future productive capacity while lowering emissions, although materials, land use and reliability still need assessment.

“Green” or “sustainable” is not guaranteed by a label; compare the full life-cycle costs, rebound effects and whether damage is actually reduced.