Energy use
The amount of energy used to produce one unit of gross domestic product (GDP) indicates the extent to which economies are efficient in their consumption of supplied energy. Differences over time and across regions reflect natural conditions, structural changes in the economy, changes in the energy efficiency of particular sectors and differences in fuel mixes. In principle, the lower the ratio the better the energy efficiency. Energy use per unit of GDP has decreased in all regions of the world (Figure 1), although there are not enough data to draw a trend line for the West Asia region.

Carbon dioxide emissions
Carbon dioxide (CO₂) emissions account for the largest share of anthropogenic emissions of greenhouse gases associated with global warming (IPCC 2001), and may therefore, be considered as an indicator of human pressure on the global climatic system.
Total CO₂ emissions continue to rise in most regions (Figure 2). In Europe, the emissions have decreased slightly since 1990, partly because of implementation of stricter regulations in the energy sector, but also due to economic downturn in the Central and Eastern European countries. Per capita CO₂ emissions show a general stabilization or slight decline in most regions, with the highest average for North America (Figure 3). The increase for West Asia around 1991 is mainly due to emissions related to the 1990–1991 Gulf War (Marland and others 2003).

Figure 2: Total carbon dioxide emissions (million tonnes of CO2) by region and global, 1989–2000

Figure 3: Total carbon dioxide emissions (tonnes of CO2) per capita by region and global, 1989–2000

Consumption of CFCs
The depletion of the stratospheric ozone layer is to a great extent brought about by chemicals known as ozone-depleting substances (ODS). The most widely used of these are the group of chlorofluorocarbons (CFCs). Emission of CFCs ultimately leads to higher concentrations of chlorine in the atmosphere, resulting in the destruction of ozone molecules and a thinner ozone layer.
The consumption of CFCs is decreasing in most regions (Figure 4), following successful implementation of the Montreal Protocol on Substances that Deplete the Ozone Layer (UNEP 2003). It is expected that the gradual restoration of the ozone layer will take place, but over several decades, provided that control measures under the Montreal Protocol are adhered to by all countries.

Mountain glacier mass balance
The global climate shows signs of change, as witnessed by higher average temperatures during the last years, leading to melting ice caps and the retreat of mountain glaciers around the world (IPCC 2001). The yearly mass balance of a representative set of major mountain glaciers could, therefore, reflect the pace of global warming. The yearly balance as measured at the glacier surface represents the thickness change of the glacier in terms of volume and area. Between 1980–2001, the thickness of 30 major mountain glaciers (Figure 5) has decreased by an average of six metres (Figure 6) (WGMS 2003). Only Scandinavia has witnessed an increase, which is probably related to changes in precipitation patterns. The flow of glacier tongues reacts with a time delay of several years or even decades compared to climatic changes. The average retreat process of mountain glaciers is, therefore, expected to continue rather dramatically in the coming decades if the current trend in global warming remains unchanged (Haeberli and Holzhauser 2003).