A decade ago, numerous countries aimed for at least 17 per cent of terrestrial and inland water, and 10 per cent of coastal and marine areas, especially areas of particular importance for biodiversity and ecosystem services, to be protected by 2020.
This goal has been partially achieved, according to the UN Environment Programme (UNEP) and the World Conservation Union (IUCN) reported.
However, they criticized the quality of protection, stating that too many of those areas are isolated and do not offer sufficient free space for the creatures living there.
Some 22.5 million square kilometres of land and inland waters are protected, an area exceeding the 17 per cent goal, if reserves that do not yet have official status are included.
However, the goal has yet to be fully achieved when it comes to oceans, where protection only extends to 7.7 per cent, or 28 million square kilometres, falling short of the 10-per-cent goal.
UNEP and IUCN greeted as a success the fact that 42 per cent of the areas currently protected have been added in the past decade.
However, they called for connections to be created between areas of protection to allow for the movement of creatures and ecological processes.
Peripheral areas of reserves need to be protected and local populations better engaged, they added.
The IUCN also called for the UN Conference on Biological Diversity, due to be held in October, to adopt a target of protecting 30 per cent each of terrestrial and marine areas.