New paper out on the extent of Sustainable Intensification in England

I’ve had a paper accepted over at Science of the Total Environment called “To what extent has sustainable intensification in England been achieved?” – click here for free access to the final published version (open until 18/19/2018), and after that you can find a free pdf of the accepted post-print manuscript over on my publications page. This is the final product of the first postdoc I took on at Southampton’s Geography department in 2015-16, so it’s good to see it finally out there! It’s also my first paper branching out into Sustainability Science & Socio-Ecological Systems from my Geological/Earth System roots. Here’s a blog summary:

The background to the paper is the drive for the Sustainable Intensification of Agriculture (SI) – the goal being to produce more food with a smaller environmental footprint, as agriculture remains one of the biggest global drivers environmental degradation while global population is projected to substantially grow by mid-century. This has been a hot topic over the last couple of decades in agricultural & environmental sciences, and there’s evidence for some progress in some places. However, the process of SI itself is not sufficient if the environmental footprint is still too big to be truly sustainable – we need to make sure that SI leads to global and regional agroecosystems reaching a ‘safe operating space‘ in which no ecosystem service is degraded beyond acceptable planetary/regional boundaries. In other words, making intensification a bit more sustainable or efficient isn’t enough if the environment that agriculture depends on is still being degraded in some way.

In this study we used publicly available data to determine the progress of SI in England and two sub-regions (mostly arable Eastern England & mostly pastoral South-Western England), using it as a case study of a rich, developed country with some signs of SI occurring. We use the data to produce metrics and indices of various important ecosystem services important for keeping the English agroecosystem in a safe operating space, such as river contamination by agricultural nutrients (water quality), atmospheric emissions (air quality), the farmland bird index (proxy for wider biodiversity), and soil erosion, as well as how much food is produced (wheat yield, and meat & dairy) and socio-economic context (e.g. farm income, subsidies, labour, etc.). [It’s worth noting here that even in a rich country there are some things we just couldn’t get enough data for, making this only a partial analysis]. From this we looked at their relative trends, performed some statistical analyses to explore these trends, and then built a simple system dynamics model of the agroecosystem and make some future projections.

Here’s a key summary figure of our main results (from the graphical abstract to the paper):

Armstrong McKay et al - Graphical Abstract

Graphical Abstract from Armstrong McKay et al. (2018) showing some key intensification trends in the English agroecosystem between 1950 and 2013.

The trends above (shown as z scores, i.e. relative changes rather than the absolute values) can be split into two main phases. Prior to the mid 1990s, Wheat Yield increases as a result of conventional Agricultural Intensification driven by increased fertiliser use, with livestock population and outputs also increasing. This results in greater food self-sufficiency (i.e. less food imported), but also leads to increased environmental degradation (the thick brown line) primarily due to pollution and falling farmland biodiversity (the dot-dashed green line). However, after the mid 1990s fertiliser use decouples from yield and starts to fall (while yield stays stable), which along with falling livestock population (mostly due to the 2001 foot-and-mouth disease outbreak) leads to a fall in pollution and therefore in overall degradation.

This seems like good news, and it partially is (especially for river-water and air quality, the biggest improvers), but this fall in overall degradation masks the fact that farmland biodiversity fails to recover at all. The parallel decline in self-sufficiency also means more food is being imported to the UK, and indicates that some of the UK’s agricultural degradation is simply being ‘offshored’ to other countries to deal with instead. These trends were further analysed and confirmed by the statistical analyses and modelling, and can also be plotted against GDP per capita to show a partial ‘Environmental Kuznets Curve’ (a reduction in degradation relative to yield beyond a certain level of prosperity – implying that prosperity leads to less degradation – but critically not for biodiversity, and could also be the result of using prosperity to pay others to degrade instead). Another interesting outcome from the analysis is the despite there being some evidence of ‘land sparing’ – i.e. intensification allowing the transfer of marginal agricultural land to conservation areas, here primarily from rough grazing areas – this has not stopped biodiversity decline so far despite being mooted as a key conservation strategy (see the paper for thoughts as to why).

Overall, these trends indicate that SI has indeed begun in England, but with major negative trade-offs on biodiversity and offshored degradation. These trade-offs undermine the general SI trend, and so must be dealt with before the English agroecosystem can reach a safe, or just, operating space. In future there’ll also be the challenges of climate change (which is likely to reduce yields and biodiversity overall) and post-Brexit subsidy changes (which might affect the financial viability of farming), which will require even more SI to counteract. What this future SI will look like is hard to say, but it’ll certainly require new approaches to subsidies and agri-environment schemes that better encourage both biodiversity restoration and reduced offshoring of degradation.

For more details, go read the paper and feel free to ask me questions!

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