You’ve been told to make eco-conscious decisions at the grocery store, but what if I told you that food production may be the biggest threat to biodiversity, and the hardest challenge we’ll face in the next 40 years? Before coming on this course I didn’t have a big picture idea of this challenge, but I think all conservationists need to know what we face. This is wildlife and food security on the line.
Agriculture may just pose the most serious threat to biodiversity: the main reason species face extinction is loss of habitat. Here’s a quick breakdown of land-use by humans that to give you an idea of the scale of habitat loss for agriculture:
- We have 13.4 billion hectares of land surface on Earth.
- Of that, 3 billion hectares could be suitable for agriculture and for housing.
- We’ve already converted 50% of that for food production (it’s under cultivation).
- And the other 50%? Well it’s flat enough and gets enough rain and has soil on it, so we could grow food there, but most of it happens to be tropical rainforests. Hmm…do we really want to rip that up?
Not only does agriculture have a land footprint, it also has a resource footprint. Agriculture accounts for 30% of all greenhouse gas emissions and 70% of our global use of freshwater.
Next, let’s think about population growth and food demand. When I was born, population was 4.4 billion. We are now at 7 billion, and when I am trying to enjoy my retirement from my conservation career, we may well be past 9 billion. A recent UN report now says it will surpass that and we’ll hit 10.1 billion by the year 2100! Additionally, each of those people is going to be eating more. For many that is a good thing because they are currently undernourished. However,
More people + ‘bigger appetites’ = more food needed (2-3x more!)
So how do we do that without converting more wild habitats and while minimizing impacts? This is a major challenge that the world faces in terms of food security and biodiversity. Options have tended to fall into two camps:
a) Land sparing: increase yields on existing land and set aside other areas for biodiversity
b) Land sharing: farm the land in more wildlife-friendly ways, creating a finer mosaic of different land uses that species can tolerate (challenge: decreased yields)
So which one is best for biodiversity? Which one is actually happening?
As usual, it depends. Here are a few things it could depend on:
- Sensitive species: If the species you want to save are very sensitive to any land use change, you may want to set aside good quality habitat for them and then intensively farm another area, because they won’t even survive a wildlife-friendly mosaic. Also referred to as density-production curve. (Read Green, et al., 2005 for the full model)
- Societal preferences: Do we want to separate food production and biodiversity conservation? (land-sparing) Is it possible in the context you are working in?
- Policy environment: If you farm intensively, are the complementary policies in place to actually protect the spared land for biodiversity? (Read Ewers, et al., 2009)
- Resource footprint: Intensive, high-yield agriculture will spare land for wild nature, but we need to consider to what extent its other impacts may offset that. Impacts include: water use, phosphate use, greenhouse gas emissions and pollution run-off from fertilizers.
- Specific local conditions: these factors could guide whether we should spare land or share land: (Read Fischer, et al., 2008)
- Topography: complex areas better for wildlife friendly mosaics, big flat areas may be better for intensive, high-yield agriculture
- Overall productivity and sensitivity of the landscape (e.g. if the soil is naturally nutrient-poor, intensive agriculture will be very damaging and should be avoided)
- Land ownership patterns: many small fields or fewer large ones
- Socio-economic factors: yields are not always lower in wildlife-friendly agriculture, for example if a farmer knows his land well he can optimize yields. Also, miminizing costs (usually from fertilizers and pesticides) may be more important to the farmer than maximizing yield.
- Societal preferences (mentioned above)
- Non-food cultivation patterns: biofuels are taking up a large proportion of our arable land
- Tackling the demand side: per capita food consumption should increase for the mal-nourished, but as people get wealthier they eat more meat and dairy products which require far more resource inputs to produce. Should we be trying to change dietary preferences?
Food for thought
Population growth and increasing per capita consumption will require us to produce 2-3 times more food within 40 years! The response to that challenge from land-use planners, governments, environmental agencies and the agriculture sector will have a huge influence on the persistence of biodiversity over the next century. So,
- How can we usefully bring these people together to set wildlife-friendly food and agriculture policies?
- Who is already doing it, and doing it well?
- What role, if any, is there for the market and major grain traders of the world?
Here are some very rough notes I jotted down during a class discussion on the topic:
Balmford, A., Green, R.E. & Scharlemann, J.P., 2005. Sparing land for nature: exploring the potential impact of changes in agricultural yield on the area needed for crop production. Global Change Biology, 11, pp.1594-1605.
Ewers, R.M. et al., 2009. Do increases in agricultural yield spare land for nature? Global Change Biology, 15, pp.1716-1726.
Fischer, J. et al., 2008. Should agricultural policies encourage land sparing or wildlife-friendly farming? Frontiers in Ecology and the Environment, 6(7), pp.380-385.
Green, R.E. et al., 2005. Farming and the fate of wild nature. Science (New York, N.Y.), 307(5709), pp.550-5. Available at: http://www.ncbi.nlm.nih.gov/pubmed/15618485.
International Assessment of Agricultural Knowledge, Science and Technology for Development (2010)
Reports available at: http://www.agassessment.org/
Matson, P.A. & Vitousek, P.M., 2006. Agricultural Intensification: Will Land Spared from Farming be Land Spared for Nature? Conservation Biology, 20(3), pp.709-710.
Royal Society theme issue (2010) “Food security: feeding the world in 2050”
Available at: http://rstb.royalsocietypublishing.org/content/365/1554.toc