Powering (human) life on Earth

Our energy needs are posing a severe threat to the climatic conditions that have allowed life to exist and flourish on earth. What are the sources of energy? How do we use it? Can we make energy choices that minimize our impact on the climate? This article is a tentative step towards exploring these questions.

While energy is the basis of existence of all life forms, our energy needs and ways of meeting them have played a key role in shaping human civilization. Over time, we have moved from harnessing heat from fires to developing a collective understanding of other sources of energy, ways of converting one form into another, and a range of specific uses for each form. This knowledge has helped unlock energy for uses well beyond our basic survival (access to food, water, shelter) — in mobility and transportation, health care, recreation, communication, managing waste, research, and the discovery of even more uses. Consequently, huntinggathering societies have changed to agricultural,  and then industrial societies (refer Fig. 1).

Fig. 1. Our energy needs have shaped the evolution of human societies.

(a) Hunting-gathering.
Credits: Skinner Prout, Uploaded by Quibik, Wikimedia Commons. URL: https://commons.wikimedia.org/wiki/File:Native_Encampment_by_Skinner_Pro...
Australia_(1876,_vol_II).jpg. License: CC-BY.
 

(b) Agrarian.
Credits: Pieter Bruegel the Elder, Uploaded by Dcoetzee, Wikimedia Commons.
(c) Industrial.
Credits: William Bell Scott, Uploaded by Hohum, Wikimedia
 
 
The Industrial Revolution in 1750 marked a turning point in the course of human civilization and our relationship with the planet. We became a civilization with high-energy needs, dependent largely on fossil-fuels (refer Box 1). Every form of energy that we have used since then has had impacts on the planet — from local clearing of land and deforestation, to global changes in atmospheric composition. When we burn fossil fuels to meet our needs — carbon, sulphur and nitrogen are released as gases into the atmosphere (refer Fig. 2). Thus, any shift to more energy-intensive ways of living, growing our food, or transportation, causes a corresponding increase in the levels of carbon dioxide, methane, oxides of sulphur and nitrogen released into the atmosphere.
 
Fig. 2. Carbon, sulphur and nitrogen oxides are produced by combustion of fossil fuels in (a) Power plants (b) Vehicles.
Credits: Ruben de Rijcke, Wikimedia Commons. URL: https://commons.wikimedia.org/wiki/File:Automobile_exhaust_gas.jpg. License: CC-BY-SA.
 
This increase has a variety of impacts on life on earth. For example, it can lead to acid rain when oxides of sulphur and nitrogen combine with rainwater (refer Fig. 3). It can also result in an increase in average global temperatures as carbon dioxide, methane and nitrous oxide contribute to the Greenhouse Effect. Based on over four decades of climate data, we know that for the first time in the history of the planet, human activity has become a dominant factor in transforming planetary climatic conditions (refer Box 2).
 
 
Fig. 3. Acid rain is caused by the reaction of sulphur and nitrogen oxides with atmospheric water molecules.
 
(a) Acid clouds grow from emissions from a refinery on the island of Curaçao.
Credits: HdeK, Wikimedia Commons. URL: https://commons.wikimedia.org/wiki/File:Cloud_formation_from_refinery_in.... License: CC-BY-SA.
 
(b) Its severe effects on vegetation in Great Smoky Mountains National Park, United States.
Credits: The Shared Experience, Flickr. URL: https://www.flickr.com/photos/numbphoto/6221399095/in/photostream/. License: CC-BY-NC-ND.
 
Can we make energy choices that minimize the impact of human activity on planetary conditions? Is it possible to imagine a world without fossil fuels? A world powered by ‘renewable sources’ of energy like wind, water, and the Sun (refer Box 3)? And, more importantly, one where we consume less and, therefore, use less energy?
 
 
Something to think about as we move to new forms of energy!
 
“…..Every transition to a new form of energy supply has to be powered by the intensive deployment of existing energies and prime movers: the transition from wood to coal had to be energized by human muscles, coal combustion powered the development of oil, and … today’s solar photovoltaic cells and wind turbines are embodiments of fossil energies required to smelt the requisite metals, synthesize the needed plastics, and process other materials requiring high energy inputs…” — Vaclav Smil, Energy and Civilization, MIT Press , 2017, p. 230.
 
The energy choices we make are not just about technology: they are social, economic, ecological and political choices, with the power to affect the quality of life of humans and other life forms. 
 
The main source of energy in preindustrial times was solar power! Unlike today, however, this power was in a form captured by plants — biomass. Biomass (wood, agricultural residue, dung cakes etc.) continues to be used even today for heating and cooking in several countries, including India, in Asia, Africa and Latin America (refer Fig. 7). Some forms of biomass are also used to meet other needs. For example, floating logs of wood are used to transport goods and people down a river (what do you think is the source of energy in this example — biomass or water?). Wind powered sails enabled trade till the early 19th century. On land, wind and water (refer Box 4) have been used for at least 2000 years for milling and grinding grain, extracting oil from oilseeds, and powering industry. These were replaced by coal-powered steam engines in 1820.
 
Fig. 7. Different forms of biomass are still used in India to meet energy needs for cooking and heating.
 
While shifting from non-renewable to renewable sources of energy can reduce the amount of carbon dioxide released into the atmosphere, it is not a magic bullet — solar power plants and windmills need land (refer Fig. 8); and the machinery for both are manufactured using fossil fuels (refer Box 5). The real question then is — can we reduce how much we consume so that we need less energy?
 
Fig. 8. Setting up solar and wind farms has impacts on land-use.
(a) A solar farm. Credits: Brahma Kumaris, Flickr. URL: https://www.flickr.com/photos/brahmakumaris/13993984261. License: CC-BY-NC.
(b) A wind farm. Credits: sarangib, Pixabay. URL: https://pixabay.com/en/wind-mill-energyalternative-2251810/. License: CC0.
 
Parting thoughts…
 
Imagine a scenario where coal and oil have not been discovered. Would the use of wind, water and biomass as sources of energy have made our lives different from what they are today? How?
 

Radha Gopalan is an environmental scientist with a Ph.D from Indian Institute of Technology Bombay, Mumbai. After 18 years of working as an environmental consultant, Radha taught Environmental Science at Rishi Valley School. She is a Visiting Faculty with the School of Development, Azim Premji University, and a member of the Food Sovereignty Alliance, India.

 

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