"Consumers tempering the intensity of their use of goods and producers making the goods with less intensity of impact allowed people to multiply in population and wealth without a proportionate harm to the earth," Paul Waggoner of the Connecticut Agricultural Experiment Station, US, told environmentalresearchweb. "In the campaign to control carbon emissions, these intensities have moved to the centre of affairs as governments stated their goals for limiting carbon emissions in terms of dematerialization and lower intensity of impact."
But will this effect continue as development progresses? With this in mind, Waggoner and Jesse Ausubel of Rockefeller University, US, have looked at trends from 1980 to 2006.
Although the average global consumer enjoyed 45% more affluence in 2006 than in 1980, each consumed only 22% more crops and 13% more energy. Over this period, China’s intensity of use declined to 0.4 times 1980 levels, whereas Brazil’s rose to 1.3 times. Without the Chinese dematerialization, China’s national energy use in 2006 would have been 180% greater.
"Dematerialization and declining intensity of impact are alive," Waggoner told environmentalresearchweb. "But beware, caution is needed. Different national and international data imply diverse, even divergent trends of intensities. Nevertheless, sturdy examples of dematerialization and improving intensity of impact persist."
Writing in a paper in PNAS, the researchers detail how France’s use of nuclear power plants lowered its carbon emissions per unit of energy use to 0.6 between 1980 and 2005. In 2005 a French consumer enjoyed 50% more affluence but used only 20% more energy and produced one ton less carbon emissions.
"Globally farmers present another success," said Waggoner. "From 1980 to 2008 rising population and affluence presented a combined challenge of 2.9% per year. Consumers met part of the challenge by dematerializing food by 0.5%per year. By increasing yield per acre farmers nearly met the remaining challenge and held the expansion of cropland to only 0.2%per year."
The researchers say that we should be cautious but trust intensities of use and impact to decline. "Overlooking that they are manifestations of two well-established phenomena may sharpen fears that dematerialization and falling intensity of impact will cease," said Waggoner. "For more than a century Engel’s Law has encapsulated the general experience that the consumption of staples, like food or energy, will grow more slowly than income, which is another way of saying, 'Staples dematerialize'. Also, producers generally learn to get more from less."
As a result, rising intensity of use or impact is exceptional, and the examples of their fall are prevalent, say the researchers.
"Meeting the sustainability challenge demands that humanity counter its growing population and affluence with dematerialization and less intensity of impact," said Waggoner. "While the evidence points to persistently declining intensities of use and impact, the striving for affluence and the instinct to reproduce ourselves present arduous challenges for declining intensities to counter."
That said, the researchers believe that the acceleration of dematerialization would be more advantageous than its persistence. "The dematerialization of crop, fertilizer and wood use plus the decarbonization of carbon emission per GDP continue," they write in their paper. "And although a declining intensity of impact is hard to find for energy, it continues for other phenomena."