# Where can I find conversion factors for calculating Ecological Footprints?

Does anybody openly publish conversion factors (e.g. for miles in different modes of transport, food, etc) into global hectares for ecological footprint?

Global Footprint Network, so far as I can tell, only make this data available through licensing their software.

The ecological footprint method does not directly convert consumed resources into global hectares, at least not via a single conversion factor. Instead first the amount of required land/sea area in physical hectares is calculated by dividing the amount of resources by the yield of the specific land/sea area where those resources were harvested. The physical hectares for each land type are then converted into global hectares by multiplying with both 'yield factors' (YF) and 'equivalence factors' (EQF).

As a formula:

``` EcoFootprint = (amount resource used / national average resource yield) * YF * EQF
```

### Yield and equivalence factors

The yield factor for a land type is the ratio between the national average yield and the world average yield on that type of land. In other words it accounts for land type productivity differences between countries. Obviously yield factors vary per country and per year.

The equivalence factor for a land type indicates how much higher/lower the productivity of that land type is compared to the world average productivity. In other words, it allows aggregating different land types into one common global hectare measure. Equivalence factors vary per year but by definition not per location.

The Global Footprint Network (GFN) regularly publishes yield and equivalence factors in reports and data packages, but you have to pay a fee to obtain those unless you qualify for non-commercial educational usage (this page on the GFN website mentions the exact requirements). Alternatively you can find other reports on the Internet that mention factors for particular years. For example page 15 of this report shows the equivalence factors for 2005, and page 22 of this report mentions those for 2006

```                    2005    2006
------------------------------------
Primary cropland   2.644   2.39
Forest             1.333   1.24
Grazing land       0.497   0.51
Fishing grounds    0.397   0.41
Built-up land      2.644   2.39
Carbon             1.333
```

The second report also mentions the yield factors for a few countries in 2006

```               Cropland Forest Grazing Fishing
Algeria         0.6     0.4     0.7     0.9
Germany         2.1     4.1     2.2     3.0
Hungary         1.4     2.6     1.9     0.0
Japan           1.5     1.4     2.2     0.8
Jordan          1.0     1.5     0.4     0.7
New Zealand     1.9     2.0     2.5     1.0
Zambia          0.5     0.2     1.5     0.0
```

Chances are this data is not very useful to you, but many online reports do demonstrate how ecological footprint calculations are done. If it's only for one country you may be able to follow the reports as an example and gather the required data yourself using public information?

### Usage data

If you want to calculate the EF for a product or organisation you also need to determine the amount of consumed primary inputs. This can be rather challenging as there is no single accepted procedure here. For example, the person doing the calculation defines the exact boundaries of what is and isn't included.

I've read somewhere that there is (some?) product information available in the GFN National Footprint Accounts reports, but I can't verify this myself at the moment. Alternatively there are both open-source and proprietary life-cycle analysis (LCA) databases that provide information about the resources used to produce certain products or services (see also the info wiki of the tag). Whether or not data is publicly available depends on the product or service you are looking for. Note that older LCA data or data from other countries can be used, but may be less accurate for the product or process you are interested in.

• Thank you for the succint explanation, however I'm trying to footprint a single organization. It seems to me the missing link, then, is a set of factors that tell me the required land use of different commodities (e.g. passenger miles in vehicles, tonnes of meat, kilowatt hours of coal powered electricity) so I can work out the organizational footprint from its inputs. Are these published anywhere? Or better yet, has anybody done the computation above with them so I can go straight from organizational inputs to footprint? Commented Apr 13, 2016 at 7:20
• I know you can pay for this information - in fact I have access to it - but I'm interested in whether it's also available to people who haven't paid. Commented Apr 13, 2016 at 7:22
• @SideshowBob I've revised my answer and added a part about calculating primary inputs. Does this help? Commented Apr 13, 2016 at 14:56
• It does. If these are the GFN national accounts you mean then they don't have usage data footprintnetwork.org/images/article_uploads/… So it would seem the short answer is no; it would take effort to figure out usage data linking inputs to land types, and further effort to apply the EF methodology outlined above? Commented Apr 13, 2016 at 15:37
• I don't think the report you link to contains all available national account information. I've read that GFN also publishes datasheets that link products with global hectares, but as I mentioned in my answer I can't verify this as I don't have access to that data. Commented Apr 14, 2016 at 11:28