Resources

Decoupling: mass as GDP grows

Kilograms per dollar have fallen since 1970 (relative efficiency), yet total mass pulled jumped from 27 to 85 Gt. Nature responds to absolute tonnage, not percentages.

Has economic growth “decoupled” from physical material use? Partly. The kilograms needed to produce one dollar have fallen steadily since 1900, that is relative decoupling. But the economy grew so much that the total mass pulled from the ground rose many times over in the same period. Nature responds to absolute tonnage, not percentages.

Three series, indexed to a common base

GDP, annual mass extraction and material intensity (kg/$), 1900 = 100. Vertical axis is logarithmic. The gap between GDP and mass is the efficiency gain; but both lines climb.

Relative gain, absolute loss

In 1900 a dollar of output took 1,06 kg of material; today 0,72 kg, 32% more efficient per unit. But over the same period world output grew ×34 and the total mass pulled grew ×23. Efficiency rose; the total burden did not fall, it grew.

Where the growth came from: population or per capita?

Between 2000 and 2025 annual mass extraction doubled. How much of that rise is from there being more of us, and how much from each person using more material?

The fall in material intensity is a real efficiency gain. But what the planet sees is tonnage, not ratio, and tonnage rose in every decade.