A 2004 study for the European Commission showed that the European Union, Norway and Switzerland contain mountain-area municipalities which cover some 1 900 000 km2 (about 40.6 per cent of total land mass). These mountainous areas are inhabited by 94.3 million people (19.1 per cent of the total population of the countries covered by the study).
The study identified mountainous areas by refining methods favoured by the UNEP-World Conservation Monitoring Centre. The following were classed as mountain areas:
• areas in Nordic countries with temperatures that are similar or lower than the highest parts of the Alps
• non-mountainous areas that form part of mountain ranges
• municipalities where 50 % of their area can be described as mountainous
• not included: isolated mountain areas of less than 5 km2
It should be noted that many countries have created their own definitions of what constitutes a mountain area, which they use in their dealings with the EU institutions. Whatever the criteria, mountain areas are usually places where climate and topography hamper economic development.