Earlier this month, the United Nations Development Programme (UNDP) released its latest Human Development Report and index, which it has done every year for the last 30 years.

The UNDP's Human Development Index (HDI), which ranks countries on the basis of health, education and living standards, is a superior measurement of human well-being to gross domestic product per capita. But this year, the UNDP added another metric. It incorporated "planetary pressures" to create a new index. This index, called the "planetary pressures-adjusted HDI" (PHDI), adjusts the standard HDI by a country's level of carbon emissions and material footprint, on a per capita basis. The higher a country's carbon and material footprint per head, the lower its PHDI score.