Life cycle assessment CENV 110

Big Picture Every activity we undertake has some environmental impact But we may want to measure the environmental impact of different things Because – We may wish to chose the one with the lowest impact – Or we may want to understand how to produce the same thing with a lower impact

Some classic examples Disposable or reusable diapers -- depends on how the reusable ones are washed and how long they last Washing dishes by hand or with a machine – depends on how full the load is and how the hand washing is done

Consider a slice of pizza How much CO 2 was generated in its production? How much water was used? How much fertilizer, or pesticide? What impact did your eating the slice of pizza have on biodiversity?

What went into it? Impacts associated with raw materials, flour, cheese, sausage Lets assume it was at a restaurant Then you have the impacts of transport of the materials, refrigeration, cooking, packaging and waste disposal For each raw material such as flour What went into growing the wheat Transport, processing of the wheat into flour

LCA structure Goal and Scope Inventory Analysis Impact Assessment

Goal The intended application – Pizza for dinner at a restaurant Reasons for carrying out the study – To compare environment inputs and outputs to other possible foods – ultimately the i-phone App Intended Audience – Consumers and retailers

Scope Identification of the function, functional unit, and reference flows Identification of the initial system boundaries Identification of criteria for inclusion of inputs and outputs A model of the production process is the result of the scope process

The Functional Unit Usually an edible product at the farm gate, retail or consumer level. No issues of time or life expectancy. – The pizza dinner

The Reference Flows Identify the processes that produce the functional unit, and the inputs that go into that process – This is the important part – Farm production, transport, packaging, wholesale, preparation, waste disposal – Inputs Flour, cheese, sausage, tomato paste, salt, yeast Each of these involves energy, machinery,

The model: system boundaries What to include and exclude For example one input into food products is labor, at the farm, transport, retail and consumer Do we consider the inputs required to maintain that labor – food, energy etc. In farm production do we consider the changes associated with land transformation from native habitat to farmland? Most LCA excludes the inputs to labor. Do we include the materials that go into the roads used for transport? The buildings?

System boundaries In theory every input to the production process requires a LCA Thus the choice of boundaries is complex and as more and more LCA’s are available, it is easier to include the components of each input

Impact analysis Converting inputs and outputs to more standardized impacts Perhaps the most common one is greenhouse gas emissions – standardized as CO 2 equivalent

An example

Goal and Scope The intended application – New Zealand Lamb delivered to Europe by ship as frozen carcasses Reasons for carrying out the study – To compare NZ lamb to lamb and other meat products produced in Europe because of pressure to restrict NZ lamb imports due to CO2 footprint – To identify opportunities for reduced CO2 footprint Intended Audience – Politicians and consumers in the E.U.

Model of product flow On farm production Processing Transportation Retail & Consumer

Class exercise Break into groups of 3-5 students Make your best estimate for what fraction of the Greenhouse Gas output comes from 1. On farm production of the meat 2. Processing of the meat 3. Transportation of meat to Europe 4. In home consumption After 5 minutes we will take a survey of each groups estimates

Overall

On farm Methane from rumination 57% Nitrous oxide from animal excreta on soil 15%

Major changes and differences Selective breeding and better nutrition have increased yield per animal 22% since 1990 New Zealand lamb is pasture fed, non irrigated, and primarily uses clover (nitrogen fixing) as forage so the amount of fertilizer used is small compared to U.S. and E.U.

Breeding and nutrition improvements

Fertilizer inputs The study examined the effect on the carbon footprint of different fertiliser regimes, including eliminating all fertiliser application. The results of this work showed that by eliminating or reducing fertiliser from current average application rates, the footprint may actually be increased because any benefits of reduced emissions caused by the fertiliser were offset by lower general productivity of the farm operation – i.e. because the farm produced less pasture and less meat, the average total emissions per kilogram of meat produced were actually higher when no fertiliser was applied.

Processing

Transport

Retail and Consumer

Decisions and uncertainties

Major issues in LCA Marginal vs average impacts Depth and breadth of modelling Spatial and temporal variability Uncertainty Co-products

Study Guide Why do we do life cycle assessment? To compare the inputs, outputs or impacts of different products or production methods. What are the major elements of the scope of a LCA? Identification of the function, functional unit and reference flows Identification of system boundaries Identification of the criteria for inclusion of inputs and outputs What is the result of the Scope of a LCA? A model of the production process What is a functional unit in terms of LCAs and food? An edible product. What is the importance of system boundaries in a LCA? Since every product has numerous inputs, and those inputs themselves have inputs and outputs, we must draw the line somewhere as to what is included. What was the purpose of the LCA for New Zealand lamb production? To compare the greenhouse gas footpring of NZ lamb to other meat sold in Europe. In the LCA for New Zealand lamb, what point in the production process had the highest greenhouse gas footprint? On farm production, 80%. What was the major source of greenhouse gas emissions on the farm? Animal rumination and methane Why is the greenhouse gas footprint of NZ lamb considerably lower than lamb or beef in the U.S. or Europe? NZ lamb is pasture fed and clover is the primary forage. Clover fixes nitrogen and uses relatively little fertilizer compared to the forage in the U.S. and Europe. What is the definition of and importance of co-products in an LCA? Co-products are other products of economic value from the process that produces the primary product. In LCA it is always difficult to determine how much of the inputs and outputs of the production process should be assigned to co-products as opposed to the primary product.