A study by the Agribusiness and Economic Research Unit at Lincoln University in NZ uses a life cycle approach to calculate energy use and CO₂ emissions associated with production and transport to UK of four NZ products: dairy, apples, onions and lamb. With the exception of onion, the results are positive in the sense that even if transport impacts are considered, NZ products still use less energy and have less corresponding emissions (in case of lamb on a ration of 4 to 1). comparing New Zealand production of four products: apples, dairy (discussed in terms of milk solids), onions and sheep meat. This report comes to the conclusion that New Zealand production is significantly more efficient from a carbon equivalent than the UK equivalent even once transport is taken into account. The study also compares New Zealand imports of grapes and kiwi fruits in to the UK and compares them with Italian imports. The following points are worth considering:

• the New Zealand figures look good on CO2 partly because over 70% of electricity consumption comes from renewables - an argument for significantly upping investment in renewables here.
• the study does not mention refrigeration energy use during transport of the products. For lamb and dairy products in particular this is likely to be significant.
• it does not appear to take a seasonal perspective - in the case of apples for example the comparative advantages of UK apples in October as compared with May will be very different. Colleagues at the University of Surrey are in the process of submitting a paper on this issue.
• Another point, and in my view the most important - the data given for UK sheep meat production and UK dairy (milk solids) production are quite starkly at odds with recent research undertaken by the Silsoe Institute at Cranfield University and published by Defra.

In particular: According to the New Zealand study, the energy used to produce 1 tonne of UK milk solids (these constitute about 10-14% total milk) is 48.3 GJ. According to the recent UK study it's only 25GJ which is comparable with the 23 GJ for the NZ dairy production. the study allows another 2GJ for shipping. If milk is imported as fresh (which it isn't) or as cheese or butter (which it is) then the transport figures need to allow extra for refrigeration, which they don't appear to. Incidentally both studies take the embedded energy of capital equipment into account. Again, according to the New Zealand study, I tonne of lamb produced in the UK requires nearly 46GJ compared with New Zealand lamb which only needs 8.6 GJ. An extra 2GJ is added on for transport. However, according to the Silsoe study lamb production requires only 23 GJ of energy per tonne. It is, interestingly, still higher than the New Zealand equivalent but the figure is halved.

• The figure looks only at energy use and not at total ghg emissions. Since energy accounts for a relatively minor proportion of total ghg emissions associated with ruminant livestock production (methane and nitrous oxides are far more important) a full study will need to compare UK agricultural practices with those in New Zealand. Depending on management / livestock rearing techniques the figures could be different.
• One small point - looking at the make up of concentrate feed in New Zealand I see 'calf meal' is included. If by this they mean ground-up animals of BSE fame then this would suggest that the some of the data they are using is out of date. Am I not right in thinking that the use of animal byproducts (apart from fish) in animal feed is now banned worldwide? Please do correct me if I'm wrong.