Double good: building without cement

Cement is a problem
Did you know that cement manufacture creates 5% of all industrial carbon dioxide emissions? That matches the pollution output of the world's aviation industry. What's more, both are set to increase, particularly in China. Construction inevitably means cement for mortar and concrete -- or does it? Certainly for the likes of high-rise city blocks, nuclear power stations and large dams, there's no alternative. But what about ordinary housing? How much concrete needs to be used in that?

Wood: a partial solution with a big bonus

Building houses out of wood is nothing new in timber-rich regions like Scandinavia and North America. Wood has many advantages over bricks, mortar, steel and concrete. For one thing, it's very easy to use so buildings can be completed in just weeks rather than months. When I 'built' my first house in western Canada back in 1971, it took 3 weeks to get the entire structure completed and watertight, ready for services to be installed. When I built my house in Spain in 1989, it took more like 6 months. Why? Because there was no wood used in my Spanish house at all, that being the local style of building. Prestressed concrete beams, which are used in large numbers, are incredibly heavy to manhandle into position or cast. So are blocks, bags of cement and making and carrying endless buckets of mortar. I worked on this house throughout the construction, so I know!

The hidden bonus of wood is that it is almost pure carbon. The growing tree grabs CO2 out of the air and converts it into sugars and, ultimately, to cellulose and lignin which is what we call wood. Everyone knows that trees sequester carbon and that they are one of several natural ecosystem services -- in this case, carbon sinks -- which counter climate change caused by humans burning fossil fuels. This is the rationale behing the burgeoning offsetting business. Plant a few trees and you can pollute as much as you want. That's what people seem to assume when guilt over squandering energy overcomes them a little.


The big issue: seeing the wood for the trees
Even if it were true that you can assuage your travel/consumer/heating/airconditioning energy use by offsets, there is one problem which seems not to enter general thinking. Natural forests are carbon neutral. As fast as young growing trees grab carbon, dead and decaying trees (and forest fires) release it again: the carbon cycle. To make sequestering carbon in trees really work to reduce atmospheric CO2, the mature trees need to be harvested and stored in such a way that they don't decompose and release all their carbon again. Carbon storage is what happened on a massive scale over hundreds of millions of years, as coal formed from dead but not decayed trees. The carbon has become safely locked away from oxidation into the atmosphere... until humans came along (and you know the rest). Yet when you think about it, we are storing carbon all the time -- in the form of timber-framed housing construction and, to a lesser extent, as books in the world's libraries.

So that's my point: countries which traditionally use cement in the form of concrete and mortar to build houses should change their construction practice and build from timber instead. This change of direction has several advantages:

• timber construction locks away carbon
• it's quicker and easier
• self-build is much easier and in some countries, you can buy housing kits to do this
• it is essentially non-polluting unlike cement-based constructions which cause massive CO2 releases into the air, principally from cement quarrying and manufacture
• if real environmental costs are taken into account, wood is far cheaper
• greater demand for timber would stimulate more forestry development with yet more sequestration of carbon as a bonus. At the same time, cement manufacture would decline as demand slackened off, so reducing carbon pollution
• timber can be re-used
• timber-framed buildings are intrinsically warmer than stone, brick, block and concrete. In addition, it is simple to incorporate insulation in the timber frame
• wood is a pleasant material to work with and beautiful to look at. Concrete is messy and heavy to move around

Yes I know concrete is essential for many purposes, including the foundations (footings) of timber-framed housing. My point is simply that we could use a lot less of it -- a lot less -- if we wanted to.

Taboo topic: the population time bomb

What is the Number One Global Problem? In the time it took you to read the previous seven words, the world's population increased by around 5. That's not 5 newborns cancelled out by 5 deaths. That's an overall increase of population which, as I write, is almost 6.6 billion; over three times more than when I was born 60 years ago. Every new person is a consumer of our planetary resources, just as we all are. Some will consume much more than others depending on where they are born and whether their parents are rich or poor. All will contribute in some degree to a grim trio of familiar troubles. The more people there are, the worse they will be:

1. climate change
2. destruction of biodiversity
3. pollution

Yet you seldom see much about the population increase. Climate change is the subject of the moment and, in many ways, rightly so. But why do we have to tackle climate change? Because there are so many people. And of course all three issues are tightly interlinked, whilst looming behind them like the spectre at the feast is population increase and the inevitable overconsumption of resources. So biodiversity is being destroyed, partly by climate change but also by the human need for more food (farmland from forest; overfishing etc.). Pollution is caused by people and the gaseous part of it causes climate change. And climate change itself is aggravated by so many people causing fossil fuels to be burned for energy and industrial feedstocks.

Why don't we get serious about population? I suppose the answer must in part be the fear of eugenics. Who gets to have children? Who doesn't? Should they be 'rationed'? Many declare that there is no problem and that the planet can comfortably hold more. Others insist that their religion demands that women produce as many children as possible by forbidding contraception. Some countries, unbelievably, are worried about underpopulation. All these issues - and many similar - are dangerous: people have very strong feelings about what should and should not be done.

There's nothing new here. The problem of population was elucidated far better over 30 years ago [population 4.1 billion]:

The present [1976] population of Latin America [given as an example] is around 300 million [almost 550 million today], and already many of them are under-nourished. But if the population continued to increase at the present rate, it would take less than 500 years to reach the point where the people, packed in a standing position, formed a solid human carpet over the whole area of the continent. This is so, even if we assumed them to be very skinny -- a not-unrealistic assumption. In 1000 years from now, they would be standing on each other's shoulders more than a million deep.

It will not have escaped you that this is a hypothetical calculation! It will not really happen like that for some very good practical reasons. The names of these reasons are famine, plague, and war; or, if we are lucky, birth control. It is no use appealing to advances in agricultural science -- 'green revolutions' and the like [e.g. genetic engineering which has now leaped to the forefront of 'solutions']. Increases in food production may temporarily relieve the problem, but it is mathematically certain that they cannot be a long-term solution; indeed... they may well make the problem worse, by speeding up the rate of population expansion. It is a simple logical truth that, short of mass emigration into space... uncontrolled birth-rates are bound to lead to horribly increased death-rates. It is hard to believe that this simple truth is not understood by those leaders who forbid their followers to use contraceptive methods. They express a preference for 'natural methods' of population limitation, and a natural method is exactly what they are going to get. It is called starvation.

from The Selfish Gene, Richard Dawkins, 1976 p.119.

Full up: The world is full. There's nowhere else to emigrate to for the first time in human history. Humans now occupy the reasonably-habitable parts of every landmass including normally-uninhabitable Antarctica. Not many decades ago, countries like Australia were encouraging immigration and not many decades before that, the USA was accepting the "tired, poor and huddled masses yearning to breathe free" from overcrowded Europe. Not any more. Today, Europe is closing its borders and the US is building a fence to keep migrants out, even though much of their respective agricultural economies depend on low-paid labourforces with no right of residence.

I speak as a former immigrant. In fact, my wife and I have emigrated twice; once to Canada (1970) and, years later, to Spain (1987). In both cases, we were privileged, being educated and not without resources. Even so, the processes were not easy.

The Big Problem: As I see it, the biggest problem we have to solve as soon as possible is not climate change but population growth. If the world's population of humans was small and stable (say a few tens of millions, just to make the point), there wouldn't be a problem with climate change, biodiversity or pollution. There would be an abundance of everything: food, fuel and all the array of natural resources people depend on for their comfort and wellbeing. Those few millions could consume what they liked and they wouldn't begin to cause the problems I mentioned, simply because there wouldn't be enough of them to affect the atmosphere and oceans which control the stability of the world's climate. A small stable population of people would be benign. And they probably wouldn't be constantly warring on one pretext or another, the pretexts we're all familiar with being, generally, land and resources.

But our numbers are not small and not stable. There are nearly 6.6 billion of us, ratcheting up and up in numbers and expectations, and consuming more and more. Because we have failed dismally to even attempt to control our numbers, the result is that we have to tackle not just population growth, but climate change, pollution and biodiversity all at once.

Solutions: The de facto 'natural' solutions are already operating in uncontrolled fashion, mostly affecting the poor:

• diseases like AIDS, tuberculosis and, potentially, bird flu already kill millions
• war and genocides kill millions more (nearly 170 million lives lost to war and major atrocities in the last century)
• starvation
• disasters like hurricanes and droughts

Other more intentional methods of controlling numbers of people have achieved various levels of notoriety:

• one-child-per-couple law in China
• mass sterilisations
• infanticide, apparently widespread in countries where, for various reasons, male children are preferred to female
• abortion

The only widely-acceptable method of control has, of course, been contraception. Unfortunately, some religious groups ban it and because of this influence, the Bush administration of the USA has stopped funding programmes which delivered contraception to those who could most have benefitted from it.

The stark choices: If we do nothing and continue as we are, the planetary mega-ecosystem within which we all live will solve the problem for us -- and it won't be nice for us. Some believe there may not be an 'us' at all within just a few decades, as the planet extinguishes that life which it cannot support.

If we do something, it won't be nice either but has the potential for being rather gentler to a greater number of us than the random and dreadful effects of war, disease and starvation. In short, climate change is a deadly symptom - one of several - of an even more serious malaise. I'm not saying we shouldn't be taking radical steps to tackle the climate problem. We should, but we desperately need to come to terms with the underlying fundamental issue: overpopulation. We need, to paraphrase Winston Churchill, urgent jaw jaw. Otherwise there will be war war ... and more more...