yeh. but then if you have a further look then you'll find
small world consulting, and their
publications page links to a range of resources from one of which i imagine the figures derive. or it might have come via the vegan society
Carbon Food Calculator
Well the first one I looked at had lamb at 15.53 compared to beef's 25.13, a difference to the above table surely not explained by the contribution of New Zealand lamb to the UK diet.
This differeing set of figures is lifted from a 2008 DEFRA study to which is attached some explanation:
"This study is reporting a much greater energy use, per tonne of meat delivered to the RDC, from the slaughter and processing of lambs than of cattle. The difference arises primarily from requirement for electricity for lamb slaughter and processing which, at 19.0 kWh/head is only
c. 25% less than that required for cattle (25.5 kWh/hd) even though cattle may weigh up to 15 times more. However, the processing of lambs is more energy intensive. Total energy use for the primary processing of pork has estimated to be 8.5 GJ/t (including transport to the slaughter house and packaging) compared with our total of 14.5 GJ/t including transport and packaging). However, energy requirements for processing pork will be less as the hides are not removed.
Lamb meat is a commodity for which allocation of burdens is particularly important. Lamb meat is the main output, but mutton is an inevitable co-product that is nutritionally sound, but out of fashion in the UK. Wool is also produced and the NZ flock produces more wool per ewe than UK sheep (5 and 3 kg respectively annually). Economic valuation is the most rational way of allocating disparate burdens and was used here in pre farm gate analysis. Different data sources were examined and both MAF and the Meat & Wool New Zealand Economic Service provided data on the relative value of carcasses and the price of wool per kg in NZ. EBLEX record data on UK lamb meat prices and live cull ewe prices and the wool price is publically accessible. Some judgement was needed to resolve disparate data and it was assumed that wool is worth more in NZ as are mutton carcasses. This led to using allocations of all burdens of 64% and 74% for NZ and the UK respectively. It is considered that this subject requires an analysis of the partition of energy and protein partitioning to provide a sounder physiological basis for such allocations..
The largest source of GWP pre farm gate, was enteric fermentation in both the UK and NZ. The greater GWP arising from grazing in the UK was due to the greater amounts of fertilizer-N applied to UK pastures. The large energy input needed to process lamb, in comparison with other meats, lead to processing being the largest source of GWP in both countries. Transport, either to the UK or within the UK, gave rise to most of the rest of the GWP arising post farm gate."
So buying minimally processed whole lamb legs from unfertilized hill farms is probably better than eating mushrooms