of CO2, which is then incorporated into photosynthesizing organisms such as phytoplankton. Dissolved CO2 is combined with calcium by shell-forming animals to produce calcium carbonate (CaCO3), which they take to the ocean bottom when they die, safely sequestering the carbon.
Before the use of fossil fuels, humans burned wood and, later, crop residues, manure, and peat for heating, cooking, and light, returning to the atmosphere more CO2 captured by plants than by food consumption and bodily respiration.
The dramatic changes to the carbon cycle brought about by human activity, and greatly accelerated during the period following the Second World War, was caused by land use changes (about 25 percent of the increase in greenhouse gas release) and the use of fossil fuels (about 75 percent of the increased emissions). As a result, the average concentration of CO2 in the atmosphere has climbed from a pre-industrial baseline of 280 parts per million (ppm) to over 400 ppm—a level last reached some 23 million years ago.12 The longest continuous monitoring of atmospheric CO2 is from the Mauna Loa Observatory in Hawaii. Figure 3.3 shows the rapid increase in CO2 from 1960 to mid-2016.13
Approximately 45 percent of the excess carbon dioxide remains in the atmosphere and contributes to global warming, while 30 percent dissolves into the oceans, causing them to gradually acidify, and 25 percent is removed by terrestrial plants. Hotter, more acidic seawater leads to coral bleaching and makes it more difficult for animals such as oysters and lobsters (as well as corals) to form their calcium carbonate shells.
Figure 3.3: Atmospheric CO2 Concentration (through August 2016).
Source: R. F. Keeling, S. J. Walker, S. C. Piper, and A. F. Bollenbacher, Scripps CO2 Program (http://scrippsco2.ucsd.edu), Scripps Institution of Oceanography (SIO), University of California, La Jolla, California.
Land Use Changes
The world’s soils contain enormous stores of carbon as organic matter, composed of animal and plant residue in different stages of decomposition as well as living organisms. Altogether, soils contain about five times more carbon than is found in Earth’s atmosphere.14 For every 1 percent of organic matter in a soil—and temperate-region agricultural soils normally have between 1 and 6 percent organic matter by weight—the amount of carbon in the top 6 inches of a field’s soil is approximately equivalent to all the CO2 in the atmosphere above the field.15
With the shift to agriculture, major changes occur. The original vegetation is frequently burned, releasing CO2. In addition, soil disturbance such as tree removal and plowing result in soil organisms having greater access to organic matter and decompose it at an accelerated rate. Thus, converting forests or savannas to agriculture results in a large release of CO2 into the atmosphere and a simultaneous loss of a significant portion of the soil’s organic matter, perhaps as much as half, as organisms use increasing amounts of newly available organic matter for energy. For a prolonged period following conversion, soils are a net source of atmospheric CO2, though this can be reversed with suitable agro-ecological techniques.
From the very beginning of capitalism, land conversion accelerated due to the drive to produce profits. There was cotton to grow in the U.S. Southeast to feed the mills of England. There was sugarcane to grow in South America and the Caribbean islands. There was widespread destruction of grassland and forest ecosystems to grow crops, monoculture forests, and plantations. These practices contributed to the rise in atmospheric carbon dioxide levels.
The imperatives of seeking profits caused increased production of crops to be processed into a variety of products to stock supermarket shelves, feed animals, and supply fuel to cars with crop-based ethanol and biodiesel. This problem persists today. The push to grow more soybeans for export to an expanding Asian market was one of the driving forces for the conversion of Amazon forest to pastureland and then to cropland in the first fifteen years of the twenty-first century. In addition to the accelerated decomposition of soil’s organic matter, the common practice of burning to clear land pumps CO2 directly into the atmosphere and explains why Indonesia is the fifth largest carbon emitter.
The situation of today’s rain forests in Indonesia and Malaysia is especially problematic because many of its forests have soil composed of peat. It is estimated that the losses of organic materials following drainage and conversion to oil palm plantations have caused the release of about 3,000 tons of CO2 per acre (about 3,000 metric tons per hectare) over fifty years.15 Although palm oil is used for foods and cosmetics, it is increasingly being used as a “green” biodiesel and pushed in the European market as a substitute for fossil fuel–derived diesel. It is estimated that it will take over 400 years of growing oil palm and using it as a substitute for petrochemical diesel to make up for the CO2 generated by the destruction of the rain forest and the associated burning of land and loss of carbon from soils through accelerated decomposition.16 (Another consequence of this practice is the irrevocable social and ecological devastation of replacing biodiverse rain forest with palm oil plantations.)
In 2015, in the wake of El Niño, Indonesia’s rain forests experienced a spell of extreme dryness. Fires set to burn the felled trees from forest clearing for conversion to oil palm plantations got out of control. In August, the fires were so extensive that thick smoke settled over a region that included Singapore and Malaysia, parts of the Philippines, and Thailand. The fires sickened hundreds of thousands of people and took a severe toll on wildlife, including orangutans, our near-relatives. The New York Times reported about the fires:
Luhut B. Pandjaitan, Indonesia’s coordinating minister for political, legal and security affairs … said the country’s “one mistake” was in approving palm oil concessions on 14.8 million acres of peatlands during the past decade, which when drained and burned to clear land for agriculture emit high levels of carbon dioxide into the air.17
Calling policies that caused such ecological and human tragedy a “mistake” is quite an understatement, particularly as it was all so predictable. The Indonesian fires were the most costly “natural” disaster of 2015, causing an estimated US $16 billion in damages.18 A study by researchers at Harvard and Columbia Universities puts the number of people who will die prematurely due to smoke inhalation from those fires at 100,000.19 The 1997 Indonesian fires, also a result of dry El Niño conditions, were estimated to have caused a significant portion of the world’s CO2 emissions for that year.20
Rise of Fossil Fuels
Over the last three hundred years, there has been large-scale burning of fossil fuels to provide power and heat. Coal and then oil and natural gas are used in ever-increasing amounts, pumping CO2 into the atmosphere as a by-product.
Along with capitalist social relations and new inventions, the energy concentrated in fossil fuels was key to the speed and manner in which the Industrial Revolution took off.21 The system has grown to the point that today the burning of fossil fuels accomplishes the work equivalent of an estimated 25 billion people working 10 hours a day, 365 days a year.22 Tom Wessels, in The Myth of Progress, described the magnitude of fossil fuel consumption in other terms: “For the first time in Earth’s history, a single species is responsible for the entropic degradation of the biosphere by releasing more energy through transformation than is being replaced by global photosynthesis.”23
As increased atmospheric CO2 drives increasing
