Matthes

(I wrote this text – originally in German – as part of a university course I was teaching on Sustainability in 2019. Part of the course dealt with the concept of the Anthropocene. I read the text to my students on a walk we took through our campus, on which we made a stop at a construction site.)   Depending on who you ask, cement has either a long or a very long history: some historians trace the origins of cement back to ancient Egypt, around five thousand years ago. The ancient Egyptians probably used a mixture of straw and mud as a binding agent. Basically, cement means no more than that: caementicium, the Latin origin of the word, first meant “crushed stone” and later “binding mass”. The fact that the word cement has a Latin origin is no coincidence either: ancient Romans around the 250-150 BC also started using cement, but they did such a good job of that, that the word has survived to this day – and so has their manufacturing process. Incidentally, ancient Romans mainly used cement for their more grandiose buildings: the Pantheon, the Colosseum, and a number of walls, domes, bridges and aqueducts. However, cement was also very useful for the Roman sewage system that was being developed at the time and for the expansion of the huge road network. Still, we know – most famously because of the huge fire under Emperor Nero – that wood was still by far the most common building material. And it would take quite a while longer before cement became as ubiquitous as it is today. For all its ubiquity, I was a little surprised at how little I, as a 21st century person and therefore someone who encounters cement on a daily basis, knew about it when I started researching this topic: One of the crazier facts about cement is that the recipe for cement was briefly lost completely after the collapse of the Roman Empire, ushering in a cement-free era until it was rediscovered by the British engineer John Smeaton in the late 18th century. Incidentally, this is almost a century after Hans Carl von Carlowitz and his explanations on sustainable forestry. And it is also after the start of the industrial revolution. From then on, of course, everything happened in quick succession and today cement and concrete are as ubiquitous in the design of our human world as only plastic, steel or the internet. Today, there are almost 40 tons of concrete for every person on earth. That’s not a lot in Germany – a simple single-family house already exceeds this amount by at least twice as much. Every year, however, around half a ton per person is added and we are not stopping there. Between 2011 and 2013, China alone poured more concrete than the USA did during the entire 20th century. Concrete has become a human signature, a material that will still be detectable in the ground millions of years later and long after the supposed end of mankind. And it has taken on cultural significance: Raw concrete is chic and modern – at least it was 5-10 years ago – skate parks get their urban charm from the heavy use of concrete, and even art objects, gravestones and statues are cast in concrete to decorate our cultural landscape. And yet it is important to recognize how new our cement and concrete culture is. The history of humankind without cement is sixty times as long as that with cement. And we already know that cement also has its disadvantages: Among other things, it seals surfaces that would normally create a cooler urban climate and it emits CO2 during its production. Perhaps that’s why, when I’m on Facebook, Instagram, Pinterest or Reddit, I keep coming across pictures of daring wooden constructions that are supposed to replace concrete high-rises or pictures of tree house vacation homes with a built-in sauna and loft bed. But I’m not actually ready to give up concrete yet. I enjoy being able to flush my toilet knowing that all my waste is being disposed of in huge cemented pipes under the city and it always upsets me a little when my bus has to travel that short distance over non-cemented, cobblestone pavement on the way home and I get a good shake. I think that’s how many of us feel and that’s why we will continue to pour concrete for the time being, our urban planners will design green spaces on roofs and our researchers will work on making cement less harmful to the environment. That will have to be enough for now.

NOTE: The following is the first draft to a script I wrote for a video that was never realized. It’s about the idea of Energy Return on Investment. Give me a spade, and I give you a hole! Err, no. That’s not how this works! Give me [takes deep breath]: A spade and the necessary extremities and muscle mass; food and drink and a bed to sleep in in order to maintain my stamina; basic medical services to not – you know – die; education so I know how to actually use a spade; clothes so I don’t freeze and/or burn under irregular weather conditions; a ride to the place at which you want the hole to be dug; maybe a bit of expendible income and a few days off to actually experience some quality of life, drink some Mojitos and make some babies- Give me all of THAT and THEN I’ll give you a hole. Yeah.. Let’s leave that aside for a second and talk about oil! Oil is AMAZING! One drop of Oil can generate eighteen times the amount of energy that it takes to extract it from the ground! So say you own an oil field, because your rich-ass Grandpa Harold Hamm inherited you his: With the energy it takes to extract the oil, you could run your own fuel-based generators, produce 18 times the electrical energy and just [high-pitched] SEEEEELL that shit! Yes? Hmmm… Okay, maybe not exactly that much, because, you know, you would have to also use some of the electricity to cook your food and boil your water… and, well, some energy to refine the oil before you could even use it; some to transport the oil from the extraction site to the refinery and from the refinery to the distributors – argh, god-damnit, we forgot to build roads! Right, okay, fixed that. Then here’s some more energy to be able to transform the oil into products like plastic, lubricants, kerosin, parrafin wax, and so on; and finally some to provide for all the workers, to educate them, give them health care and, you know, allow them to make babies. And Mojitos. All that being done, however, we can still generate enough energy to allow us to reinvest the excess into scaling up, innovation, and that 50 meter yacht that I always wanted – Honey, we’re gonna be rich! [awkward pause] Bummer of course that our oil resources are somewhat depleting… Arrgh, okay scrap the oil plans – I can’t live off only one yacht for the rest of my life! But hey, no worries, I already got a new idea: RENEWABLE ENERGIES! What? Solar Power has only an Energy Return on Investment Ratio of 10:1? In the Sahara?! How much do we need to survive? 11:1? Aw, crap! How am I ever gonna save up for my second yacht – nay – floating villa?! Okay, let’s sit down and look at the numbers: Bad news is that oil EROI is declining pretty fast. In 1999 we were still at an EROI of 35:1. Today we are only at 15:1. Fast forward to 2035 and the EROI ratio will be at 10:1 and then all I will be able to do is to sell those yachts – or, well, I could take away some of that unnecessary health care from my workers… OR – and here’s some good news: I could go for renewables that are on the rise anyways! Renewable energy technology is constantly being improved, the EROI constantly on the rise, and we might see a day when solar energy is as viable as oil was in the past! Yay, problem solved, everyone is happy! Hm… But what to do in the meantime? How can we keep things going and not fall into a hole where we have neither enough energy derived from renewables nor enough energy from our fossil past? How to avoid the unimaginable no-Yacht-nor-Floating-Villa-scenario?! I mean there’s always nuclear energy. Nuclear energy can sustain us today without the eminent need for some fossil resource or super-efficient photovoltaic technology. Needless to say, however, that nuclear comes with its own set of drawbacks. So the true, the glorious and shining ready-for-paradise-solution is just to recycle the living shit out of what we have already! Let’s simply build our world in a way that everything we use can be reused. After all, according to the first law of thermodynamics, energy doesn’t go away. We just have to recover it and the ecological paradise is but a few steps away. What’s that? A second rule of thermodynamics? Pshh, go away – no – just – away – argh alright, I’ll have a look… [mumbling]Second rule of thermodynamics…increase of entropy… aww crap! Guys, send back the pink clouds! No paradise for us anytime soon…. No – how can I put it… do you know when you mix milk into your coffee and then the milk just magically separates again from the coffee? No? Yeah, my point exactly! Just found out that that’s also true for pretty much all other things in the world. Separating Milk from Coffee after it’s poured in is about as laborous as sorting flower seeds out of an ocean of powdered sugar. So again we’re lacking the energy for more energy. Okay, so what now? Where’s the perfect solution? Turns out there maybe is no perfect solution! Maybe the best we can do is to get better at renewables as soon as possible, get out of fossils as quick as possible and in the meantime put systems in place that can help us make more use of less energy. Not very sexy, I know. Nor very yacht-and-or-mojito-inducive, but oh well… Maybe there’s at least still energy left for some baby-making.