On January 17, 2012, The Smithsonian Institute celebrated 40 years as the World’s largest Museum and Research Centre, with 40 predictions for the next 40 years.

The number one thing you need to know about the next 40 years, according to the Smithsonian is:  “Sophisticated Buildings Will Be Made Of Mud.”

I agree with this prediction wholeheartedly. I have been sharing the optimism that this may one day be the case for at least the past 30 years and I have witnessed the gradual uptake and definitely more general and wider acceptance of mud or earth buildings over this time.

It appears I am in the good company of free thinking minds with both wisdom and foresight – and please remember this is the Smithsonian’s first prediction and not the 40th. This maybe gives us an idea of the either the certainty or the urgency of the need for it to be true.

I have long posited that earth is the ultimate green building material and that earth building is appropriate, renewable and sustainable technology. Earth building techniques known to Australia include mud brick (adobe or earth brick), pressed earth brick, rammed earth (pisé de terre or pise out west), cob, wattle and daub, dug out (Coober Pedy style), earth render and earth bag. The common feature is that the fabric of the building is composed of raw unfired earth.

In its purest form, clay is the binder and a matrix of silt, sand and gravel are the fillers. This is generally the composition of subsoils, although it is possible that suitable earth materials can be optimised by blending those individual earth components and by using additives such as fibre and stabilisers to create a mixture that will enhance various material characteristics. The mixture may be prepared either wet or damp before being applied, compacted or moulded and through evaporation, the earth becomes hard and durable.

There is a strong case for utilising raw unfired earth as a building material for what our industry calls earth building. Some common myths and doubts exist, but earth building has many virtue. I believe there is a need for research, but it is important that we learn more from tradition and vernacular building and blend this with modern methodology, building science and standards to create the sort of built environment that the Smithsonian Institute predicts.

Earth building can solve particular problems the world faces, such as trying to find affordable disaster resistant buildings that are also healthy, energy efficient, desirable and sustainable. It allows for buildings that are truly sustainable – not greenwashed, but buildings that make inroads into the reduction of energy and resource flows that humanity needs worldwide especially in developed economies.

There is no question that one fifth of the world is living beyond what is currently sustainable. The consequences of finding the resources and energy required in meeting the aspirations of the other 80 per cent presently working on closing the gap is by far the greater problem. This is according to the OECD and discussions coming out of climate change talks. Tackling greenhouse gas reduction in the built environment head-on at all levels from embodied energy through to operational energy, demolition and reuse is the only way to achieve very challenging targets. Looking to the lessons of a more sustainable past for lessons for a sustainable future will help keep the target on track. Earth building can be a big picture, holistic and equitable solution to the needs of the world’s 7.3 billion people.

I hope you now understand why the Smithsonian Institute is thinking about the possibilities of earth in sophisticated buildings. Their prediction spanned the next four decades, although it is probably necessary to state that the process of building some very sophisticated earth buildings started 11,000 years ago and continues today. There needs to be a better recognition of the sophistication that has already been achieved along with the fact that one-third to half of the world’s population currently live in earth buildings. Some buildings are very basic self-built shelters, some were sophisticated hundreds of years ago and are still adequate today and some modern buildings are indeed very sophisticated by current standards. What is common is that all types provide lessons for contemporary problems in meeting tomorrow’s standards and challenges.

Earth buildings exist on all continents bar Antarctica. It is true that sophisticated buildings of mud have already existed. Man’s first urban settlements 11,000 years ago were earth. Early pyramids were made of earth, as were the Hanging Gardens of Babylon and large sections of the Great Wall of China. Earth buildings in China can be counted in the millions as they can in India and Africa. There are hundreds of thousands of earth buildings throughout Europe and the UK, some as old as 500 years and still in use. The earth fabric within most has been disguised by render and forgotten throughout time.

In Yemen, 400-year old earth skyscrapers reaching 10 stories exist and offer comfort without either heating or cooling in an extremely hostile environment through natural conditioning linked to thermal mass. The ancient Sumerians built refrigerated mud buildings that could keep ice confectionary cool into the hot summers. NASA has considered building with lunar soils in proposed plans for colonisation of the moon. Earth building played a huge part in the settlement of the Australian colonies and very early buildings not the subject of redevelopment pressures and were properly constructed still exist.

Australia now leads the world in rammed earth building with architects winning awards with stunning examples of what can be achieved with earth. Right now in Europe, factories are constructing enormous rammed earth panels with robotic rammers. The panels are cut into huge blocks, transported to site and assembled in the same order using mud mortar. An Italian inventor has designed and built the world’s first 3D mud printer that can automatically construct small earth buildings.

Earth has been a sustainable solution for urban settlement for 11,000 years. Populations are urbanising and lessons of the past point to masonry being the best solution for sound isolation, security and fire, pest and vermin control. Modern earth building is a sustainable solution worth investigating. It can provide safe, healthy, durable, comfortable, affordable, desirable and sustainable buildings in subsistence economies and developed economies alike.

The Smithsonian Institute’s predictions are not at all unrealistic.