Seasonal and unprocessed vegetables and fruit
Both peak oil and climate change require us to reduce our reliance on fossil fuels. Reducing meat consumption and reducing food waste are probably the biggest steps we can take, but how we buy fruit and vegetables is also a significant factor.
There has been much debate recently, in the press and public policy circles, as to whether "local is better" in terms of greenhouse gas emissions. It has been demonstrated that it may be better in greenhouse gas terms to grow tomatoes outdoors in Spain, and truck them up to the UK, than to grow them in the UK in a heated greenhouse.
However, if we really want to reduce our oil dependency and greenhouse gas emissions, neither of these options is a good one. Ideally, we would choose to eat tomatoes during the few summer months when they can be grown in the UK without heat - and eat something else in the other months.
In fact, if we choose to eat UK produce out of season, we will always need to choose between the lesser of three evils: energy-intensive production methods, long-term storage, or importing. Each of these has its costs in terms of energy use and climate change:
- Production methods to "extend the season" include heating greenhouses, or using fleece to protect early crops from frost. The latter is less energy-intensive, although since fleece is ultimately made from oil it may eventually become impractical. Heating greenhouses is a very expensive process, and many UK tomato growers have packed up in recent years as the price of oil and gas has risen. The few that remain mainly use heat (and carbon dioxide to boost plant growth) that is a by-product of other processes, as British Sugar do at their plant in Wissington, Norfolk. Unfortunately some of these processing operations may themselves become unviable as a result of peak oil, so this is not necessarily a long-term solution.
- Long-term storage includes freezing and canning. Both of these use vast amounts of energy - typically resulting in greenhouse gas emissions of the order of 2kg of CO2 per kg of produce, not dissimilar to the cost of flying the produce in from Africa. The other kind of storage is where crops such as apples or potatoes are stored in coldstores for months at a time. To achieve the very longest storage periods these coldstores also have modified atmospheres. This kind of storage is less energy-intensive than freezing or canning, but again may not survive rising energy prices.
- Importing produce by road from European countries like Spain or Italy may indeed be less costly (in energy or climate-change terms) than the other options - though it still has a significant that we might do better to avoid. Similarly bringing apples or bananas by ship from the Caribbean or South Africa has only a moderate impact (although recent research has revealed that the climate-change impact of shipping is around three times greater than had previously been thought). Airfreighting - a technique used to transport fragile crops like soft fruit, salads or mange tout from distant countires - is hugely damaging in environmental terms. There remains an ongoing debate as to whether this environmental cost can be justified by supposed social benefits. However, in the context of peak oil the debate is academic: airfreight of food will simply not be an option. The cost of aviation fuel has risen by 80% in the year to April 2008. The Financial Times reported on 11 April 2008 that five US airlines had folded in recent months, and even major airlines like AlItalia are reported to be in trouble as a result of the rising fuel price.
Eating seasonal, fresh produce can be an adventure rather than a drudge. This is particularly true where the produce is home-grown. Box schemes and other types of community-supported agriculture provide another effortless way to keep in synch with the seasons, and it can be exciting to open the weekly box to see what the week has brought. Many good box schemes do supplement their local seasonal produce with carefully-selected imported (but not airfreighted) produce, in order to ensure that there is always a good range of interesting produce in the box. Nevertheless, a diet based on a local organic veg box will have a carbon (and fossil fuel) footprint that is a small fraction of that of the typical supermarket shopper who uses a mixture of frozen, canned and airfreighted produce.