Climate Friendly Food

By Jonathan Smith and Mukti Mitchell, September 2009
including research by Rupert Hawley and Jenny Hall

Background

This calculator accurately calculates carbon emissions and sequestration from all farming activities. This knowledge offers a marketing tool to attract carbon-conscious consumers as well as a guide to farming practices that reduce emissions and increase sequestration.

Data comes from 30 of over 100 studies considered, including sources from the IPCC and DEFRA. We believe it to be the most comprehensive and accurate agricultural carbon calculator available today. In particular it covers soil organic processes and sequestration, which are omitted from most other agricultural calculators yet can be the greatest contributors to net carbon emissions or sequestration. We aim to expand the calculator for non-organic farmers and growers in 2010. There is a guide next to the Total Weight of Produce box. Our full list of references can be found here.

How to use

Navigate to each section using the tabs at the top of the page, and enter details for your farm over a one-year accounting period.

Greenhouse gas emissions are represented in carbon dioxide-equivalent (CO2e) where 1kg Methane = 25kg CO2e and 1kg Nitrous Oxide = 298kg CO2e. Emissions - sequestration = net CO2 emissions. So a positive balance indicates net emissions and a negative balance indicates your farm is a carbon sink.

To help with the process, a farmer and grower checklist can be used prior to beginning your carbon calculation.

Conditions for Use

You are welcome to use the carbon calculator for free. However, you are not permitted to make your results public, or use them for marketing purposes, without entering the Climate Friendly Food Participatory Certification scheme. This is currently only available in the UK.

Disclaimer

CFF collects entered data in a farm carbon database. Information is strictly confidential and will not be shared without your permission. Data will be used by CFF for education, promotion and funding monitoring purposes without identifying individual farms. We hope this database will become an invaluable resource in coming years.

CFF cannot take responsibility for the effect that any errors in calculations or original data used may have on organisations or individuals. We aim to update the calculator every year according to latest best science.

This page calculates the CO2 emissions from the embodied energy in materials i.e. the energy used to manufacture materials.

We have used a depreciation of 1 year for building materials and consumables and 10 years for machinery. Therefore only enter data for materials and consumables purchased this year and for machinery that is less than 10 years old.

We aim to develop the calculator for construction CO2 emissions based on size of building to spread emissions over 10 years as in machinery. Until this is developed new buildings emissions are accounted for in year of construction, and does not appear in subsequent years calculations.

Enter data for either by weight or volume (do not double account) and take good note of the units used as these vary from item to item.

This section calculates CO2 emissions from external distribution systems and off-farm food processing. Any produce you deliver using your own vehicles will be covered under the fuel section of the calculator, so this is for all external collection & delivery systems. These are complicated areas, so here we use figures from national studies to give average figures for the distribution and processing of different types of food. It looks complicated at first, but there is a guide next to the Total Weight of Produce box.

Firstly, the calculator asks for the total weight of produce sold beyond the farm gate in a year. If you dont know the weight of produce sold but do know the number of veg-boxes, animals, eggs etc. there is a guide at the bottom of the page that will help you calculate the weight of produce. Secondly the calculator asks you to give a breakdown of produce going through different distribution systems. You can enter this breakdown either as estimated percentages or as specific weights, but unfortunately you cant mix and match. If using percentages ensure that the total shown below adds up to 100.

Internal delivery systmes: Produce delivered using your own vehicles are covered under the fuel section, but you can enter details here so that the percentages add up to 100. If you are entering by weight instead of percentage then you dont need to enter the weight of produce delivered using your own vehicles.

External delivery systems: For different types of produce there is generally a choice of four external delivery systems, and you might be sending your produce through one or all of these. The first choice, "Courier delivery of known distance" is for simple systems in which you know exactly how many miles the produce is travelling to reach the consumer. For more complicated systems, where the produce is going to box schemes or multiple outlets of unknown distances, chose the most appropriate of the other three systems.