resources - life cycle assessment

Question 1

what is the purpose of a life cycle assessment?

Answer 1

attempts to put a number on the environmental impact of a product

Question 2

stages to carrying out a life cycle assessment

Answer 2

• firstly, assess the environmental impact of extracting and processing the raw materials. many modern products contain plastics and metals such as copper.
• assess environmental impact of the product during its lifetime (example a toy could require batteries. batteries release large amounts of toxic waste
• assess disposal of product after its useful life (many modern products contain a number of harmful chemicals. these chemicals have to be disposed of carefully. requires energy + also takes energy to transport useful products for disposal)

Question 3

environmental impact of extracting and processing plastics

Answer 3

polymers (plastics) produced using crude oil. first oil has to be extracted from ground and transported to oil refineries. hydrocarbons have to be separated and then cracked. finally, polymer has to be produced. requires lots of energy generated by burning fossil fuels which contributes to climate change.

Question 4

environmental impact of extracting and processing metals

Answer 4

extracting metals also takes a huge amount of energy. ore has to be dug out of mine and then transported for processing. metal then has to be extracted from the ore + this can produce large amounts of toxic waste products. once produced raw materials, manufacture our product, package it and transport it. all these stages require energy + may release harmful waste products

Question 5

life cycle assessment for plastic bag vs paper

Answer 5

• plastic produced using chemicals from crude oil. paper made from timber (wood from trees)
• crude oil is a non-renewable resource. timber (trees) is a renewable resource as we can plant more
• extracting crude oil can be harmful to habitats eg if there is an oil leak. felling trees for wood is also extremely destructive to habitats such as forests
• both crude oil and wood need to be chemically processed. this requires lots of energy + releases waste products. making paper requires huge amounts of water
• plastic bags strong, reused (bin liners). paper not strong, tear, used once, thrown away
• at end of lives, both bags have to be transported either for recycling or to landfills. paper bags heavier than plastic so take more energy to transport
• plastic is non-biodegradable. they remain in environment for a very long time. they are a major form of litter. fill up landfills. however paper breaks down quickly when wet.

Question 6

problem with life cycle assessment

Answer 6

• even though we can measure the use of water and energy, + the production of some waste products, we cannot be certain how damaging these are to the environment. this means in some cases have to make estimates or value judgments. not always accurate
• can be biased to support claims by advertisers