Environment | Science | Nature
The ruins of Aleppo are a reminder of the fragility of peace and civilised behaviour. Lying in the Fertile Crescent, roughly equidistant between the Euphrates and the eastern Mediterranean, it has been a vibrant commercial and cultural centre for thousands of years. It was home to a bewildering number of ethnic groups and religious affiliations, such as Sunni, Shia, Alawite, Ishmaeli and various Sufi sects, but five bishops guiding their various Christian flocks—some speaking Aramaic, the language of Jesus.
Over the millennia it has been ruled by Akkadians, Hittites, Persians, Armenians, Romans, Byzantines, Arab Sassanids and Umayyads, the Egyptian Mamluks and the French, amongst others.
Over the years I have had the good fortune to work in nearby Tel Hadya and to spend time in Aleppo. Although I knew the dangers of crossing the Baathist regime, the city appeared very safe, largely at ease with itself and to be gradually liberalising. Until the US interventions in Kuwait and Iraq, I saw few women wearing veils or headscarves and the Armenian restaurants in the old city were well patronised. Hopefully the city will rise from the calamity of the current civil war but the ruins should be a fearful warning of the thin line separating us from barbarity.
The availability of energy defines the way life on Earth has developed, as well as many of its physio-chemical characteristics. In this unpeeling of the logarithmic processes of change, R. Gareth Wyn Jones identifies six rapidly shortening energy revolutions from the energising of the first living cell to the exploitation of fossil fuel for the industrial revolution. A seventh revolution now challenges us: our own response to man-made climate change. Can we manage it or are we too late?
The war was started by internal divisions within Syria but has been aggravated by regional and foreign powers pursuing their own interests and vendettas through proxies. However, another fact has also worried me. In the years leading to the civil war, Syria suffered the worst drought in 400 years. I do not know how much this contributed to the uprising but the susceptibility of the livelihoods of many farmers to drought and their dependence on pumping water from retreating groundwater aquifers were plain to see.
The war rumbles on, and the fear and despair that have gripped Syria are palpable. As climate change and global warming tighten their grip on populous countries, one must ask whether this is a harbinger of a more stormy and violent future. What will be the fate of drought-stricken Iran or parts of the Indian subcontinent where farmers are being compelled to cope not only with debts but with temperatures in the high 40s and humidities so high that they override the human body’s temperature controls? Will some groups be protected and others not? Will communal violence erupt?
Well before James Lovelock and Lynn Margulis popularised the Gaia hypothesis in the late 1950s my old professor in Bangor, W. Charles Evans FRS, was preaching the essential continuity of the geospheres and biospheres. He conceived chemical threads leading from geology and geochemistry through soils and their abundant microbiology and the various atmospheric inputs, to higher plants and animals, be the latter humans or ruminants. Strongly influenced by his vision, my own work has led me to perceive further threads leading from cell biology to human societies from the subsistence farmers and herders of the Maloti mountains in Lesotho to the inhabitants of the bustling megapolises of Karachi and London.
Two chains stood out. The first was energy and the consequential ability to do and control work and to generate power. The second was homeostatic regulation. The former is of course fundamental to the climate change issue as a dangerous manifestation of the age-old relationship between energy flow and biology. The latter is, however, far less well known. I became aware of the concept after I started working on plant nutrition and stress adaptation. This led to an appreciation of the importance of homeostatic regulation in plants.
Energy enables work and power, which in turn lead to ordered complexity. New sources of energy or step changes in energy use have catalysed greater complexity, be it in pre-human biological systems and their structures or in human society and our constructs. In the case of cells and organisms, these ensure that core internal functions are maintained, if possible well maintained, and flourish in the face of external change and internal demands. Consequently, as biological and latterly human complexity has evolved, these stabilising systems must also evolve and develop to accommodate each new challenge. These simple concepts have profound implications for our modern dilemmas, including how we react to the multiple challenges of global warming and climate change and the Anthropocene era.
In this volume I outline the six major energy step changes that have come to define our planet’s bio-, hydro- and geo-spheres over the last 4 billion years. I explore the evolution of the stabilising homeostatic mechanisms and other emergent properties arising from these energy revolutions. I then summarise the background to the seventh revolution, the response to anthropogenic climate change. This is the revolution in which we are now embroiled but whose outcome is profoundly uncertain.
I highlight six critical step changes in the transformation of energy into material complexity, suggesting that these have led to the overwhelming global dominance of Homo sapiens and have shaped our society and indeed the whole of the biosphere. These transformative events were: (1) the energising of the first living cell(s); (2) the harvesting of the Sun’s incoming radiant energy; (3) the evolution of complex, eukaryotic cells with substantially more energy per gene; (4) the investment of addition food energy in the complex and powerful hominid brain; (5) the acquisition of more energy for human society through settled agriculture; and, finally, (6) the use of fossil hydrocarbon fuels to fire the Industrial Revolution.
These ‘revolutions’, especially the early ones, were very slow-burning affairs, stretching over vast periods of time and, in each case, the dominant system of the previous regime retained its biological, geological and social significance. Each ‘revolution’ was not a single event but a complex series of changes and innovations that together made for a step change in the history of our planet. These six events were the planetary game changers.
Gareth Wyn Jones is an Honorary Fellow of Bangor University, and Professor Emeritus of plant biology and bioscience. He enjoyed a long association with the university as a student and researcher under Professor Charles Evans, as a lecturer, and as one of the founders and leader of Bangor's Centre for Arid Zones Studies. He was formerly Professor in Bangor's Schools of Biological Sciences and Agricultural and Forest Sciences.
Homo sapiens has emerged globally dominant from these energy revolutions. Paradoxically, this dominance is now both threatening and being threatened. The lifestyles of the affluent and aspirational classes, the main beneficiaries of the sixth revolution, are open to being undermined by the impacts of their own GHG emissions and by climate change and Anthropocene degradation. The lives of the very poor, who have benefited least, are being made even more precarious.
It is important to appreciate the scale of human energy demand in a country such as the United Kingdom. In the fourth revolution beginning only about 2 million years ago, the investment of some 500 food calories per day (only an additional 0.6 kWh per person per day) in additional neurons and in brain power was the catalyst. It levered in, after two further energy revolutions, astounding human power, technical prowess and material wealth. The resulting energy demand is nothing short of staggering. In Britain, Mackay has estimated the average individual energy use in 2007 to be some 195 kWh of energy per day, equivalent to ~250,000 kcal/food calories a day. That is a total average individual energy demand 100 times our basic metabolic requirement and at least 50 times more than that which supported our ancestors. Some over a certain age will remember sitting in front of a single-bar electric fire on winter’s night trying to keep warm. For them, this comparison may be useful. A one-bar electric fire uses 24 kWh a day. So it is as if we have about eight such fires running continuously, day and night, all year long to support our individual lifestyles!
The human metabolic requirement is only about 2.2 kWh per day. Mackay, more generously and realistically in the modern world, allowed us 2,600 kcal per person per day—that is 3 kWh each. In the developed world, meeting this basic need requires a substantial investment of energy in farming, fertilisers, agrochemicals and the food supply chain equivalent to about 15 kWh per day per person. This reflects the disparity between our primary food energy requirement and the energy inputs into the agricultural and commercial systems that supply us. However, our primary food-energy budget is dwarfed by the totality of terrestrial and marine transport, space heating and cooling, air travel, industry and just consuming.
Given the huge inequalities in wealth and lifestyle, the energy and consequently CO2 footprints of the jet-setting elite from any country must be at least double, probably treble, the mean, even in the ‘rich’ countries. Energy use permeates all aspects of modern life. This, as we have discussed, is supplied largely by burning fossil fuels. (Note that the total GHG emissions from the food chain, which include methane and nitrous oxide, are significantly greater than those due to CO2 alone. These mainly arise from land use changes, e.g. ploughing land or cutting down forests, as well as transport and agrochemicals.)
It must not be imagined that our dependence on hydrocarbon fossil energy has reduced our dependence on the world’s annual photosynthetic resources. In a detailed study, Imhoff and Bounoua concluded that mankind, in the seventeen years from 1981 to 1998, utilised approximately 20% of the annual global terrestrial net photosynthetic production (NPP) to meet our demands for food (animals and crops), wood products, fibres and other goods. They also noted significant regional variation. NPP utilisation varied from about 80% in south-central Asia and a little over 70% in Europe, to only 6% in South America. The global population was under 6 billion when this study was carried out. It is now about 7.7 billion and is not projected to equilibrate until nearing, or maybe exceeding, 10 billion. Consequently, food, fibre and fodder demand can only increase; an increase compounded by the taste of the growing middle class in China and elsewhere for ‘western’, McDonald’s-type, meat-heavy, high-fat, high-sugar diets. Thus, the proportion of the world’s NPP claimed by humans seems destined to increase. Although there may be a minor but ecologically distorting offset by anthropogenic atmospheric CO2 and N (NO3– and NH4+) fertilisation, it seems certain there will be a catastrophic squeeze on the energy supply chains of many other species ...
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