The Problem With Concrete

The Problem With Concrete

Hi, this is Alex from MinuteEarth, in a special
collaboration with Bill and Melinda Gates. Around the world, almost 7 million people
move to, or are born in, cities every month. Which can be super efficient, because when
people live close to each other, it’s easier to move people, power, water, and basically
everything else around. But it’s also a problem: in order to build
all the buildings and infrastructure these new city dwellers will need – the equivalent
of a new New York City every single month for the next 40 years – we’re going to need
a lot of concrete. And for the health of the planet, concrete
is a one-two punch. Well, technically cement is the heavy hitter. It’s the thing that, y’know, cements the
basic ingredients of concrete – sand, rocks and water – together into a single, useful
material, and it’s a mean source of planet-warming carbon dioxide. Cement’s one-two punch comes from how it’s
made. First, we have to heat limestone – which typically
requires us to use lots of fossil fuels, which emit CO2. Second, once we do that, the limestone chemically
breaks down into lime, which goes into the cement along with some other stuff, and carbon
dioxide, which goes into the air. In most industrial processes, the energy used
to run machines and heat stuff up is the overwhelming source of carbon dioxide, but with cement,
when the limestone itself breaks down, it releases even more CO2 than all the other
parts put together. All told, for every ton of cement we make,
almost a ton of CO2 gets released. Today, cement’s double whammy leaves it
responsible for 8% of humanity’s carbon dioxide emissions – that’s more than airplanes,
ships, and long distance trucking put together. And as we keep on building a new New York
City each month, the emissions from cement are only going to go up. So, what to do about cement? We could build some of these new buildings
out of other materials and we also could use less cement per building. For the cement we do use, we could try to
manufacture and heat it using renewable sources. And these things would certainly help! But the real game-changer would be to stop
using limestone itself in cement – then it wouldn’t release CO2 when it breaks down. And there actually are alternatives out there
already, some of which can reduce the amount of limestone needed – and others that can
replace limestone completely. So far, most of these alternatives are either
too expensive to make or too early in development or are being adopted tentatively because concrete
is such an important structural material. But some alternative cements are already being
used successfully in major buildings and bridges around the world, and when we use cement with
less limestone, or with no limestone at all, as the foundation for all of our new cities,
we’ll reap some seriously concrete benefits. This video was produced in collaboration with
Bill and Melinda Gates, who every year write a letter describing their philanthropic efforts. In this year’s letter, they discuss 9 surprising
things they learned in 2018, and how those surprises have prodded them into action. In addition to being surprised by the rapid
death of old-school textbooks and the fact that toilets haven’t changed in a century,
they were also troubled by the environmental impacts of global urbanization – and we were
happy to help them explain one of the impacts in a concrete way. To read the letter yourself, click the link
in the description or visit

Comments (100)

  1. All the comments – can't readily find a proper & succinct response – so coming from a former believer of emissions causing global warming, here:1-It's not carbon emissions added to our atmosphere! Plant life love eating CO2 and balance out human/animal activity.2-It is the heat emitted from the final cement product in roads and buildings that retains heat from the Sun. These structures do not create heat, they retain it.3-It is also the final cement product that keeps the soils from absorbing and filtering the planet's WATER readily, a deterrent to plant and animal life.So: It's nothing to do with cow farts (gasses). It is the final product that retains heat. Even this retention of heat doesn't affect overall climate, but only limited geographic areas. Even go from city to suburb to country to wilderness?Where does the heat come from? If you said the Sun, you're correct. This is the power our ancestors recognized as the true engine (and god) of life.

  2. Some are trying to find out how to solve the problem! One more time science could help!



  5. Carbon dioxide is NOT a poisonous or harmful substance. Plants thrive on CO2 and in return produce oxygen. Plants need the CO2 and animals need the oxygen. The "carbon footprint" myth is part of an insidious leftist/socialist agenda to deprive people of their God-given rights. And YES there IS a GOD!

  6. Concrete is bad for your health.. Try cement instead

  7. CO2 barely contributes to global warming, HUMANS don't cause global warming. I am willing to debate anyone who disagrees.

  8. Uhhh….. The Hummaans!!! THE HUUUMMMAAAANS!!!!!!!!!!

  9. i mean does lava beat rocks

  10. I just realized I've watched for a fair time but I forgot to subscribe

  11. Don't plants inhale CO2 so why is it a problem photosynthesis help control carbon dioxide you guys make it sound bad when it's actually good what's really damaging the earth is its age how do you think the climate change during the ice age because of the age of the earth right so that's why we're not the cause of climate change its just that the earth is aging and there might be another age similar to the ice age.

  12. How it fells to eat cement


    cement stimulate your concrete

  13. What about using CO2 capture on the lime production and produce synthetic fuel with it? You can do this either on limestone or on concrete recycling via nuclear energy, without too much of a problem and this would allow for carbon neutral concrete, without needing to invent new kinds of material.

  14. Bill Gates?!!!??! How much money did he give you?

  15. CO2 is plant food. Why is this always forgotten?

  16. Break down the co2 into carbon and oxygen

  17. I would simply like to know if you consulted with construction industry professionals in the writing of this video? All of these methods are already being heavily used in areas other than these big cities. The reason why big cities are not using those methods is because of our dated regulations.

  18. To bad they didn't mention that concrete sucks in CO2 as it sets, so overall concrete CO2 emissions are much lower.

  19. we could also ask EEUU to stop invading every fucking country that has oil
    that would help more

  20. So, how did the Romans build empires of concrete?

  21. The cement problem is not a problem. its good news. see

  22. But what if the country has too many earthquakes

  23. Tell AOC to ban concrete.

  24. Neat, I never knew they used cement alternatives when rebuilding the 35W bridge, hopefully this one will last a little longer.


  26. Just plant more trees

  27. We need more windmills, they don't need concrete!!! Oh wait…

  28. Carbon Tax = solved

  29. Your research isn't all that concrete.
    Not to mention the alternatives (slag) still leave your dreaded carbon footprint anyway.

  30. man isn't putting enough Co2 into the atmosphere to have any impact

  31. What about steel buildings?

  32. It’s the work of an enemy stand

  33. so all I have to do is melt some rock put some sand and water in and I have cement?
    I don't get that

  34. We need carbon capture on a large scale. We can stop emissions from energy production and transportation, all it takes is scaling up manufacturing and decommissioning the fossil infrastructure. We need carbon capture for things like cement, and airplanes, and rockets, because we aren't close enough to solving them to get the engineering done, and also implement the change across the whole industry, all within the time we have left. Obviously, we should keep working on sustainable cement, but we need to start scaling up carbon capture too.

  35. How about rethinking whether living in a city is really a good idea?
    – Nothing necessary is produced within the city, food and energy have to be brought in from the outside.
    – For skyscrapers you'll need steel and concrete.

  36. The more accurate title for this video is "Problem With Making Cement"

  37. So, it's the problem of burning fossil fuels. It's not a special problem.

  38. you make this sound so important but truth is that One volcanic eruption releases more c02 then all of that put together, and eruptions happen daily.

  39. Isn't fly ash bad too? Don't know how. But, I see some cement packages say 'no fly ash' on them. So, thought fly ash would be worse than cement.

  40. You forget to mention one very important detail which is that cement reabsorbs the carbon dioxide emitted in the production of burnt lime when it solidifies into concrete in the reaction:

    CaO + CO2 -> CaCO3

  41. Lime stone +water = cement

  42. Need earth bender

  43. How to not use limestone:
    Edit:not only Minecraft is getting popular but it's player's wood plank house is saving the earth
    Btw not hating

  44. co2 is good for planet and nature (every owner of a fishtank will tell this), so stop this lies

  45. bruh, methane is more efficent at trapping heat, and it comes from farts

  46. Wow, I was gonna slam this video hard, but it looks like you guys took care of that. Thanks. It’s not easy being everyone’s dad.

  47. I expected this to be about coasts being destroyed because wenn need the sand.

  48. As someone who works in the construction industry as a technical system planner, i.e. in the planning of technical building equipment, I unfortunately take a rather negative view of developments: paradoxically, something as durable as buildings is always treated more as disposable products. The supposed increase in efficiency through precise adjustment to the use within the building leads to the fact that all technical installations are torn out again in the course of renovations, only to install expensive, resource-consuming systems in the buildings again instead of cleverly aligning the buildings for as many applications as possible and not ignoring environmental protection. In German there is a word for it: "verschlimmbessern" – it means to make things worse, although you want to improve them, because you get too involved and perfect all possible details until the big picture disappears from view.

    I also take a critical view of the fact that politicians, due to housing shortages, and construction companies, due to cost savings, are now trying to speed up construction. Sounds good at first if you optimize something, but there are limits. At some point you can't optimize without causing problems. A large construction company in Germany, for example, is demanding that construction should function just-in-time in the future, as it does in the automotive industry – with perfectly manufactured components already at the production stage. Cut-outs for pipelines and air ducts, for example, are not only to be knocked back into the walls afterwards, but the concrete is to be saved in the production of the wall. Great, but what if the planner had too little time to coordinate all the pipe and air ducting or if the architect wants to change the room or the future user suddenly has other ideas that need to be incorporated quickly? This is no exception, but the rule in this industry! In the worst case, the stated cut-outs are not correct and have to be corrected on site. What do I ask, have we won with this? Why does everything always have to go faster, faster, faster instead of cleverer?

  49. if we could make power with CO2…..

  50. If you build with wood it would be the Chicago Fire except everyone in the world is about dead.

  51. wooden buildings are a huge fire hazard, too little concrete or too much use of less tried-and-true alternatives will result in architectural catastrophic failure, continued use of concrete as is will choke humanity off the planet.

    we're not gonna solve this problem. massive die-offs are inevitable.

  52. @MinuteEarth Are you guys talking about the Global Change Institute Building at the University of Queensland?

  53. Woah now. CaCO3 is heated to form CaO and CO2. CaO is mixed with H2O to form Ca(OH)2. Due to relative solubilities and reactivity, this slowly reacts with CO2 in the atmosphere to reform CaCO3. This is a slow process for thick slabs of concrete but is necessary. Ca(OH)2 dissolves in water. CaCO3 does not. In fact, you can prove concrete is calcium carbonate. Spill acid on it. It bubbles like all carbonates do. This means that part of the video is highly inaccurate. This means with the exception of decomposing the lime into CaO and applying it, it is carbon neutral.

    Tl:dr; lime + heat = burnt lime. Burnt lime + water = slaked lime. Slaked lime + CO2 = lime. It is a complete circle and you have to pay attention to the net of CO2 in the atmosphere, not just the released CO2.

  54. CO2 is necessary for life. It is NOT toxic or bad for the environment.

  55. Lol… Back to cutting down trees. 🤣😂🤣 I suggest you do a video on AirCrete.

  56. What if we use mud

  57. but if you use wood, you have to cut down trees which are good at capturing CO2

  58. I thought it said BILL GATES

  59. Where Chicago's first poured curbs lasted over a hundred years, identified with their pinkish hue. Their replacements are being replaced on a 15-year basis.

    An anyone living on a corner has witnessed updated ADA requirements result in corner intersecting sidewalks replaced every five years within just past two decades.

    And the more frequent curb replacements assures nearby trees given valid reason for their shortened service life required removal.

    At the same time data shows how overtime even cement sequesters traffic output carbon similar to trees along roadways. And just like when trees get ground up into mulch, road cement getting ground down to be used as new aggregate for new cement also totally releases all it's built up carbon.

  60. we need to find a new building material that leaves no carbon footprint we are a damn intelligent race im sure we can figure this out!

  61. Haven’t visited this channel in like 5 months >.<

  62. I can teach my friends !

  63. I guess Gates isn't living on a dirt floor. Maybe its marble?
    Or granite? But, by God, "don't dare use concrete now".
    The Gates were scared to death with prison-assassination threats from federal prosecutors like Mueller and Comey. "Give us control of your money or we take it anyway and your family does in poverty and shame" can be tough coming from the DeepState operatives in the Justice Department. Thus, The Gates Foundation's birth. All for the benefit of the global Islamo-Nazi caliphate.

  64. Also keep in mind the sand used in concrete is "extracted" from nature, leaving behind severely disrupted environments…

  65. But I love putting them in my Minecraft builds!

  66. CO2 is a God given gift for trees and other plants. We need more CO2 for a greener planet to make eatable plants grow better which is our only chance of feeding all the world

  67. So what if we made air scrubbers? A natural type of fliter like trees.

  68. I think you forgot one point about cement. To dry hard, the CaO in the cement is capturing atmospheric CO2, to convert back to CaCO3.

  69. But plants eat carbon dioxide, so it's fine right? Just put a Central Park everywhere in each City to combat Co2.

  70. We need to find a different way of making concrete or another material all together!

  71. As soon as I heard Bill Gates was involved I turned it off.
    Because anything he advocates must be evil.

  72. They should have mentioned that the cement's solidification CONSUMES CO2.
    Ca(OH)2+CO2—>CaCO3 + H2O

  73. oof 999 dislikes ;-;

  74. So concrete is good for plants by releasing co2

  75. aaaaaaaaand: solved ! (that was easy !)

  76. Me: Concret-san is bullying EARTH-CHAN

  77. 0:35 didn’t know cement could fail no nut November

  78. Bill and Melinda Gates, you know them. The ones that force fed common corps down our throats. And yeah, lets cut down more trees to save the world…. really? How much are they paying you guys to say this crap and how much does it actually cost to produce one of your videos?

  79. Is carbon dioxide bad? Beacause plants breath it in change of oxygen

  80. I have a solution for this, whom may I talk?

  81. “Did you actually Collab with Bill Gates” Thuy Bui 2018

  82. I just came from the cyanobacteria video that was talking about how Co2, nitrogen, and phosphorus were making cyanobacteria kill us. It all links together, doesn't it?

  83. Well in Canada, a cement company used a machine to trap carbon dioxide IN the cement…

  84. If you make a New York City out of wood some idiot will burn it all down

  85. How to make cement, get lots of clay from the bottoms of ponds

  86. The puns and jokes here are golden.

  87. just plant trees lmao

  88. Easy way to better explain science to non native students. Your videos are excellent and helped me to boost my score In TOEFL exam. Thank you MinuteEarth!

  89. finally something civil engineering related

  90. Lets do nothing ,maybe earth will be destroyed by something a bit later

  91. Some more information, from 2015 –

  92. Oh dude, know that the burning of CaCO3 uses gas fuel, not liquid fuel like gasoline, diesel, etc. And gas fuel wont produce carbon byproducts. And actually, they dont use wood as fuel xD.

    Second, you said that mixing the lime into cement releases CO2 to the air. How can? If yes, what's the benefit of doing so? All we know that concrete needs O2 to get their strength…

  93. it needs to have spikes so when you bash someone’s head in it it will be lethal

  94. Scientists need to do this in a green house, full of trees. 8% of CO2 emissions gone.

  95. replace concrete with wood…
    so cutting trees to prevent CO2 emissions is the solution.

  96. I'm just out here trying to turn this blue ball grey.

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