The recent IPCC and CCC reports considering strategies for achieving a limit of 1.5oC on global temperature rise above pre-industrial levels had a lot to say about the role of the agri-food system in emissions and sequestration. The part played by trees, particularly afforestation on land freed up as a consequence of reduced consumption of meat and dairy products, has some associated metrics, although the global target to halt deforestation by 2020 now looks like another milestone set to be missed. Another relatively straightforward intervention relates to peat-land, particularly in upland areas, with the recommendation to engage in large-scale restoration. In areas where such terrain is used for agriculture, there will inevitably be economic consequences for farmers and growers which will need to be dealt with sensitively, but the ‘how’ of restoration is established. The difference between healthy and degraded upland peat ecosystems can be stark, as illustrated in the pictures below on the Staffordshire moorlands taken only a mile or so apart. The final area for attention is carbon sequestration in agricultural soils. Core techniques for doing this seem relatively well-defined, including low-till methods and the use of cover crops, but reliable metrics for long-term sequestration have yet to be developed (or at least have yet to be published).
The lack of metrics is especially relevant in the context of a carbon market across sectors where land managers would be rewarded for ‘carbon farming’ on behalf of other actors. I’ve written about this before (see previous posts ‘Political Will or Political Won’t’ and ‘Down to Earth’) and a combination of factors is bringing the subject to increased prominence. I’ve attended three events with the Sustainable Soils Alliance over the last couple of weeks and it is clear that there is substantial interest in the question of soils generally and sequestration metrics in particular. At this point I should return to the observation I made in the recent ‘Plane Trees’ post about Ryanair’s emissions. The commercial success of the airline has resulted in it becoming one of Europe’s top ten industrial emitters but on relative measures their published data suggest it holds up very well against other operator’s intensity figures. It has also signed-up to an IATA absolute measure to halve industry-wide emissions by 2050 against a 2005 baseline. As lower-priced air travel has made it more accessible and more common, this halving grows as a challenge and the use of sequestration for offsetting must surely be attractive, at least until alternative propulsion systems replace the jet engine. With CAP set to be replaced on UK farms within the next 2-3 years, the first stage may be public money for public goods before transition to a full carbon market. Quite what a policy approach (in England and Wales) might look like will have to wait for the publication of the Environment Bill which enacts the recent 25-year environment plan, expected this autumn. By some measures, autumn might be viewed as already having arrived and the business of government in Westminster remains focused on the UK’s relationship with the EU, so quite when it will see the light of day remains unclear.
At the start of the year press reports raised the question of whether Prosecco consumption was ethically acceptable given, amongst other concerns, the soil erosion impact of the land management practices employed in vineyards in the growing region. A paper published in May by Pappalardo et al in PLoS ONE 14(5) quantified the impact of conventional land management techniques, which involve leaving bare soil between rows of vines with an alternative approach wherein grass is encouraged to grow across the vineyard. Even with control measures the loss was 1.1kg per bottle against 3.3kg per bottle if the soil was unprotected. It may be somewhat unfair to pick out Prosecco, as the grapes for other wines are grown in a similar manner and Italy is not alone in facing the issue. Any vineyard where the vines run along a slope rather than across it whilst capturing the maximum sunshine is at risk of significant soil loss due to run-off. The pictures below show vineyards in Southern France less than a kilometre apart, the regional equivalents to Prosecco being Blanquette and Crémant, where radically different approaches have been taken. Some organic growers in the area even go so far as to use the fact that they manage their land to minimise run-off as part of their marketing. The short-term costs in competition for inputs and of controlling the length of grass such that it doesn’t interfere with product quality and harvesting have to be set against the longer-term cost of the fields being washed away; another area where well-judged policy and incentives are necessary to drive the best overall outcome.