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What are your earliest memories of using a computer? Mine are about learning to code in GW-BASIC and playing Space Invaders – all of those on majestic, hulking cathode ray tube monitors (CRTs). I miss them (the CRTs, not GW-BASIC or Space Invaders). Flat-screen LCDs have taken over the desks which CRTs ones proudly reigned over. Technological development forever bounds towards the newer, the sleeker, the thinner, the lighter and the ‘better’. Lying in its wake are the remains of the old, the bulky, the boxy and the clunky – wallowing in their obsolescence, the callously abandoned detritus of the electronic world.
I am waxing nostalgic about CRTs because my folks back home recently retired my first CRT. It was a special day when they brought it home for the first time. We were getting a computer – with a colour monitor! (Although the operating system, That Which Shall Not Be Named, made me lose my faith in humanity.) We became best friends – inseparable. Oh, the joy of the crafting the perfect code for string manipulation, while the rest of the normal, athletic, well-coordinated and socially well-adjusted kids played outside.
(Left) Things that my cool (and completely imaginary) self did for fun. (Right) Things that I actually did for fun. (It was even better when you spelled profanities in the string-manipulation code. Palindromes were difficult in that case – five-lettered or odd-numbered profanities are not so common in English. But if you tried French…)
You see, I get attached to my old gadgets and electronics. They are supportive, hardworking and kind (except the ones haunted by poltergeists). A part of me (the weird part) misses the audible whoomph followed by the alarming yet reassuring crackling sounds my CRT made when I turned it off. (Static?)
CRTs vs. LCDs – Environmental impacts: I am also thinking of CRTs and LCDs because I was recently comparing their environmental impacts when modeling electronic waste recycling scenarios. So how do CRTs fare against LCDs from an environmental standpoint? Graph 1 below shows different the environmental impacts of a 17″ CRT monitor vs. a 17″ LCD monitor. Each impact is scaled to 100%. These individual impacts (such as climate change, ozone depletion, human toxicity etc.) are also called impact categories.
Graph 1: Environmental impacts of CRTS vs. LCDs. The different impacts numbered 1 through 18 are also called impact categories. From this graph, which of the two has a lower environmental burden overall?
We now have a problem: If we were to buy a monitor solely based on a lower (overall) environmental footprint, which would we choose – a CRT or an LCD? Compared to LCDs, CRTs have lower impact on climate change (impact category 1). But the reverse is true in the case of marine ecotoxicity (impact category 11). If we choose CRTs over LCDs, does the lower impact of CRTs on climate change outweigh their higher impact on human toxicity?
To answer that, we need a way to compare the different impacts against each other. How do we compare, say, climate change (measured in kg-CO2 equivalent) with water depletion (measured in m3) or metal depletion (measured in kg iron-equivalent)? We can do that using one of my most commonly used but least favourite tools: Math. A clever mathematical manipulation allows us to convert the different units of the impact categories into one dimensionless unit. This is called normalization. (We won’t go into the details of how we will normalize the results, that’s for another post. But we will look at the normalized results.)
“Without normalization, the indicator results are in quite different units, e.g., kg CO2-equivalents for climate change and MJ primary energy for fossil energy depletion.” [1] When we normalize our earlier results and plot them in Graph 2 below “it becomes clear to which impact category a product contributes relatively much”. [1]
Let’s look at the normalized results:
Graph 2: Now do we have a clearer picture of the relative environmental impacts of CRTs and LCDs? (Note: The Y-axis is dimensionless after normalization.)
Things are not looking good for the CRTs. The results of Graph 2 can but further aggregated into three categories to show the potential impacts on human health, ecosystems and resources.
Graph 3: The impacts of CRTs and LCDs on human health, ecosystems and resources. Which has a lower environmental burden now?
Again, we need to normalize the results:
Graph 4: Normalized impacts of CRTs and LCDs on human health, ecosystems and resources.
The results can be further aggregated into a single score and expressed in eco-points (Pts), where 1000 
Pts = the total annual environmental burden caused by the average person in Europe. Lower score (that is lower eco-points) implies lower environmental burden. Final scores: CRT 67.2 Pts, LCD 61.3 Pts. If we were buying a monitor and had to choose between a CRT and an LCD, we may use this single score result to support our decision. Most rating systems for the environmental impacts available today are based on similar approaches. (Examples: GoodGuide, Cradle-to-Cradle, Timberland’s Green Index, BASF’s Eco-efficiency etc.) These ratings are usually grounded in life cycle assessment (LCA), a method for estimating environmental burdens of products and processes. (More details on LCA to follow in a future post.)
GoodGuide rating system
Conclusion: We saw that CRTs and LCDs have different environmental impacts. The overall environmental burdens for LCDs are less than those for CRTs. Perhaps I should not hold it against LCDs for taking over my beloved CRTs. But let’s be honest: why do we choose LCDs over CRTs? Probably because LCDs take up less desk space.
Despite my maudlin love for them, the CRTs had it coming. I guess LCDs are OK – they are impersonal, non-imposing, have style and lower environmental burdens overall. But the old CRTs? They had character.
Image sources: Wikipedia, Goodguide