1 Notes for Lectures – ENVIR 202 Earth, Air, Water winter 2003 9 i 2003 P.Rhines 1. INTRODUCTION We will encounter several very different views of the environment: McNeill’s history (which has considerable sociology and philosophy built in) which though inspired still leads to gloomy feelings; the up-beat can-do environmentalism of Amory Lovins (www.rmi.org); the skeptical conservatism (hey, no problem) of Bjorn Lomborg (www.lomborg.com) and the opposing views of scientists (www.anti-lomborg.com). The early part of McNeill’s book (up to p20) briefly reviews the historical trends that lead up to today. The combination of great increases in population, economic activity (related to ‘wealth’) and technological devices all multiply together to define the impact…the ‘footprint’… of mankind on the environment. This trio of effects has often been described, for example by Paul Ehrlich in his book, The Population Explosion [McNeill only mentions the first two of these]. McNeill is one of a growing number of scholars trying to put both ‘the planet’s history’ and ‘the people’s history’ together, with the aim of improving our (and its) future. We will talk this term about some deep problems relating to life on Earth, and in the grandest notion of all, the life ‘of’ the Earth, described as a problem of evolution. McNeill talks about ‘rats’ and ‘sharks’: versatile adaptability (rats) vs. supreme adaptation to one particular environment (sharks). 20th C. humanity is more shark-like: stable climate, cheap energy, but this is dangerous strategy. “In the 20th Century, societies often pursued a shark strategy amid a global ecology ever more unstable—and hence more suitable for rats….The same characteristics that underwrote our long-term biological success—adaptability, cleverness—have lately permitted us to erect a highly specialized fossil-fuel based civilization so ecologically disruptive that it guarantees surprises and shocks…we have created a regime of perpetual ecological disturbance..” (McNeill p xxiii). “ The human race, without intending anything of the sort, has undertaken a gigantic, uncontrolled experiment on the Earth. In time, I think, this will appear as the most important aspect of twentieth-century history, more so than world war II.” (McNeill p 4). This ‘experiment’ has many aspects. One is global climate: the temperature, rainfall, winds, soil moisture, Arctic ice and so on. We will consider the greenhouse ‘experiment’ in the Air and Water units. Another is the development of diseases and epidemics: the combination of individual health and transmission and evolution of disease in crowded, fast-moving global populations. While we cannot study health issues in detail, they are much in our minds. However, it is the health of the planet and all its creatures that should concern us. Human beings are just one, dominant species. “…in natural systems, as in human affairs, there are thresholds and so-called nonlinear effects.” (p 4). Numbers tell the story. Very roughly 80 billion humans have been born since we evolved a few million years ago, and more than 6 billion of these (7.5%) are now alive. The human body, viewed as an engine that converts chemical energy from food into glucose, then into mechanical work is about 18% efficient (This number would increase if we included our heat production as well…how would you measure this?).2We can put out no more than about 1 horsepower (=746 watts) and that only for very short periods (here I disagree with McNeill, p12, who argues for only 100 watts). Try this idea out on the bicycle-light in the lab. Over a work day we cannot put out much more than an average power of a puny 20 watts (take a 2500 kilocalories per day food diet, convert it to watts and multiply by the 0.18 efficiency factor above, using 4.185 Joules = 1 calorie). Yet by mining the photosynthetic energy of the deep past (fossil fuel) we have multiplied our strength. McNeill introduces the idea of ‘energy slaves’…the work done for us by fossil fuel, expressed in units of human power output. The ‘average’ citizen of Earth has about 20 such energy slaves (McNeill p.14). How many energy slaves does the average American employ? This rate of mining of energy has increased by a factor of 5 in the 19th Century and another factor of 16 during the 20th Century (McNeill p15). The global use of energy from fossil fuels and renewable energies amounted to 3.8 x 1020 Joules per year in 1999 (Physics Today, April 2002). With about 6.3 billion (6.3 x 109) people now alive you can calculate what each of McNeill’s “20 energy slaves per person on Earth” is worth in watts of power. The rich nations (roughly 1.2 billion people) used energy at a rate about 7 times that of the poorer 4.1 billion people (1990 figures). That is, 2/3 of global energy supplies are used by the richest ¼ of the population. We will see quite a few energy numbers, but one I find particularly sobering is: driving along in your car a moderate steady speed, you are using 100,000 watts of power from burning gasoline. Your efficiency is about 1%. This is calculated by taking the roughly 20% efficiency (that is, 0.20) in turning the gasoline into mechanical work, multiplied by the ratio of your weight to the car’s weight, roughly 0.05 (we are talking about people-moving here). The 99% lost could be recaptured and sold for a profit. Actually, the efficiency is far worse than 1%, if you attempt to figure in the costs of mining the energy and bringing it to you gas tank. Economists might argue about this, but the transmission, conversion and extraction of energy is a long, complex chain. The efficiencies of each link in the chain multiply together to make a very small net efficiency. The ‘true cost’ of a gallon of gasoline is much greater than the $1.20 we pay (far cheaper than fizzy drinking water). It leads directly to social-political costs involving wars, dictatorships and great inequality of health and happiness across the face of the Earth. We begin to see conservation as a supremely valuable ‘hidden energy source’: a much more efficient and less polluting vehicle could be on the roads today (www.hypercar.com). Conservation throughout our lives could increase the likelihood of a happy future for everyone: people, insects, plants. The problem is really not,