“Peak Carbon” Occurred a Decade Ago

5 October 2016 Geoffrey Craggs, JP, Research Analyst, Northern Australia and Land Care Research Programme


In studies published by the science magazine Cosmos, James Curran, formally the CEO of the Scottish Environmental Protection Agency, states that, on a global scale, trees and plants reached “peak carbon” 10 years ago.

CIMMYT's multi-crop, multi-use zero tillage seeder at work on a long-term conservation agriculture (CA) trial plot, left, at the center's headquarters at El Batán, Mexico. The residues retained on the soil surface and the permanent raised beds are in clear contrast with the conventional plot on the right. Photo credit: CIMMYT.
Figure 1: Sustainable soil management in El Batán, Mexico. Source: CIMMYT Images, Flickr.


Peak carbon is based on the ability of plants to sequester carbon dioxide (CO2) from the atmosphere through a process of photosynthesis and convert into a form of soil carbon.  The effectiveness of this process is largely governed by the amount of vegetation which, in turn, is influenced by the size of the area covered and how long vegetation remains over that area.  In hot, dry areas, for instance, plant growth can often be limited to a season or less.

The 2006 “peak carbon” level is attributed to global warming. Using data provided by the Mauna Loa Observatory in Hawaii, the researchers identified that rising levels of CO2, have resulted in a decline in the amount of carbon that plants are able to absorb – the rate of appetite loss is commensurate with increasing global temperatures.

For sustainable plant growth to exist, soil carbon is essential.  But plants also need access to water, nutrients, trace elements and microbes that support such growth.  Without these components, effective plant growth will not occur.

The concept of “peak carbon”, therefore, is determined by the ability of plants to absorb CO2.  But it is the decline of the other components that is leading to the concept of “peak carbon” as much as a decline in carbon itself.

In part, the decline in the ability for plants to absorb CO2 is influenced by rising temperatures causing stresses from water shortages, drought, increased threat of fire, weed and pest invasions, storm damage and salt invasion. Certain types of land management and environmental practices contribute to soil degradation, leading to poor soil health and the consequential effects on plant development and growth.  Clearly, the key to combating the concept of “peak carbon” is developing healthier, sustainable soils.

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