More than two decades ago 150 nations signed the Convention on Biological Diversity, aiming to stop biodiversity loss by 2010. That target was later moved to 2020, but it is also unlikely to be met.
The task is far from a simple one, considering that we are now losing species at rates 1,000 to 10,000 higher than at any point of human history. Time is pressing and conservationists are exploring new ambitious strategies. One idea being considered involves reserving half of the Earth to conservation, which has gained much attention over the recent years. It has been promoted by influential global initiatives like Nature Needs Half and Half-Earth project.
Now we have some solid scientific analysis on the topic, pushing the idea of this conversation project one step further.
A study published by Zia Mehrabi and her colleagues in a new issue of Nature Sustainability provides “an initial assessment of the potential global trade-offs” of agriculture and ambitious conservation goals, emphasizing the competitive nature of these uses. Based on global land use, protected areas, biodiversity, and crop production data-sets, the research team modeled the possible changes in agriculture that various conservation strategies might cause: reserving half of every ecoregion, half of every country, or half of Earth’s total land cover.
The largest scale scenario also considered that the distribution would depend on the fitness of territories for conservation: i.e. Brazil might have more than 50% of its territory reserved, while China, a bit less. Strategies were further modeled in two pathways: vast nature-only parts or mosaic fragments of conservation and human use.
Key findings suggest that in the largest scale strategy, where vast areas would be reserved for nature, 10% of all animal feed and bio-fuels would need to be sacrificed, as well as 11% of crop food calories. In a mosaic scenario, those losses, however, diminished to zero.
In the scenarios based on the protection of ecoregions, the losses increased to 25% of non-food calories and 29% of food calories in vast area designation scenarios, which meant almost fully dropping down for food uses in mosaic settings but remaining high for feed and energy applications. The researchers say that they have found “no clear pathway to give half our planet to nature at a scale that maintains ecosystem connectivity and still feeds the world, without at least some nations or sub-populations losing out.”
These estimates, however, do not consider various strategies to balance priorities and keep productive lands in use, so that each region has its own strategy to go about conservation. The study also doesn’t take into account the importance of biodiversity for ecosystem resilience and ecosystem services, and how they secure food production, whereby loss of biodiversity we’re witnessing might lead to much graver consequences than slight decreases in food production, especially considering that the world is currently throwing away a third of all food produced, which is twice more than needed to feed all the people suffering from hunger globally.
It could be argued that it’s abundance of food production and food waste that is really driving much of the ecosystem destruction. Might it be that less space for food may lead to better care of it? And what would a half-Earth decision mean for resilience of our socio-ecological systems? Would it make more space for nature and allow humanity to still thrive, or deepen a divide between humans and other living beings? These are hard questions, requiring moral reasoning and political deliberation, and science alone will probably fail to provide a comprehensive single solution.
The study’s authors admit that much can be achieved from decreasing food waste and transitioning towards plant-rich diets. The team also acknowledges that “The ecological, political, sociocultural, economic and business models needed to sustain a global conservation project of such scale and ambition over decades and into the deep future, have yet to be developed.”