Currently, about 15 per cent of the earth's land and 7 per cent of our oceans are protected in nature reserves. It doesn't sound like much, but how much is enough? Some conservationists are arguing that 50 per cent of the earth must be reserved to effectively protect biodiversity. The Nature Needs Half organisation and a recent book called Half Earth by a Harvard biologist are pushing this idea and it is gaining traction.

It is an interesting way to approach the problem of declining biodiversity. Even if the number appears arbitrary it is generating conversation around questions we need to answer; at a global level, but also a local level. These questions include:

  • What are the objectives of conservation - is it just about environmental goals, or is it also linked to social and economic outcomes?
  • What are the tradeoffs - Are there any? Up to a point protecting the environment also generates social and economic benefits, but eventually, there will always be trade-offs and we need to decide how we deal with them. 
  • What type of protection generates the most benefits - Do we lock up large tracts of land in already unpopulated areas or establish an integrated pattern of wildlife areas?

50 per cent may seem far-fetched. In working out if it is we may arrive at the optimal level and form of biodiversity conservation.