The importance of soil carbon sequestration in reaching NetZero 2050
In our many conversations around the office kitchen table, as well as in our lectures and presentations in Australia and abroad, one of the biggest recurring themes is the relationship between soil health and climate change.
As our CEO is also an author on land degradation and climate change, we allowed ourselves to grab the following extract, with a few edits, from Philip Mulvey and his daughter Freya’s book Ground Breaking: Soil Security and Climate Change. The basic tenet in this book underpins all that we seek to achieve at Carbon Count.
A number of scientists worldwide, including hydrologists, meteorologists and soil scientists, believe the greatest anthropogenic impact on climate change is not CO2 emissions, but the land use changes we have made, especially how we practice agriculture. Our research has brought us to the same conclusion.
Reaching zero emissions alone won’t stop the Earth heating up. In our presentations and conversation , our aim is to broaden the discussion around what remains the most pressing problem of our time: what is causing climate change?
The answer is heat. And what causes and contributes to generating excess heat is at the heart of solving our human–made climate catastrophe.
Excess heat starts with land use change and its impact on soil security. Securing our soils is crucial to preserving the clean water we drink, the food we eat and the air we breathe. It is integral to preserving our biodiversity and the ecological sustainability of our environment, as well as regulating our climate.
Soil security and climate change are the defining emergencies of our time, and the two are intimately connected, in Australia and globally.
What we continue to stress whenever we promote soil carbon farming practices, is that our landscape practices are as important to climate change as atmospheric processes, of which greenhouse gases, GHGs, are only one.
The key to carbon dioxide’s (CO2) strong influence on climate is its ability to absorb heat emitted from our planet’s surface, preventing it from escaping out to space. CO2 and the other GHGs do not in and of themselves generate heat. While GHGs are an important component of climate change, their outsized influence is responsive, not causative.
It all starts with the sun shining through our atmosphere warming the Earth’s surface (as shown in Figure 1 above). Heat emitted from the sun is solar radiation. When solar radiation, the sun’s energy, reaches Earth, some of it is absorbed by the atmosphere, land and ocean, and the rest is reflected back into space as infrared radiation.
Svante Arrhenius (1859-1927) found that rather than infrared radiation escaping back into space, some was being trapped by GHGs and re–emitted in all directions. That is, GHGs are partly transparent to incoming solar radiation and only reflect a portion of the outgoing infrared radiation back as it is exiting the atmosphere. Some of the re–emitted infrared radiation does escape to space, but the rest further heats the earth’s atmosphere, or is absorbed by the land, and the majority, over 90 per cent, is adsorbed by the oceans.
The greenhouse effect is a natural physical process. It is necessary for human survival; without it the Earth’s average surface temperature would be too cool. The problem arises when excess heat is absorbed by the land, oceans and atmosphere.
Excess heat to the atmosphere is in part due to the enhanced greenhouse effect, when emissions from human activity contribute more heat–absorbing gases in the atmosphere. Increased concentrations of GHGs in the atmosphere in the last 50 years is not natural and contributes to additional warming of the Earth’s surface.
However, while what is regulating the earth’s atmosphere is multifaceted, principally it is a two-step process: a heat source and a blanket.
In concentrating on GHGs, which act as the blanket, investigation and understanding of the heat source has largely been forgotten. The ultimate heat source is the sun’s energy which is foremost absorbed by the land. GHGs are not the heat source, but the blanket that only traps outgoing infrared radiation.
The heat source for GHGs to reflect then, is what the land does with solar radiation. Increasing the size of either the way the land processes solar radiation to create infrared radiation or the volume of GHGs in the atmosphere, increases global atmospheric heat. Increasing the size of both accelerates the heat rise, having a compounding effect.
Greater investigation and concerted effort directed to addressing the first element of the process, the heat source, and what alters the heat source, is critical to mitigating anthropogenic climate change.While carbon neutrality or decarbonisation are helpful in reducing the blanketing process, and thereby the acceleration of anthropogenic climate change, reaching net zero emissions will not reverse anthropogenic climate change if the source of the infrared radiation is not also reduced.
Reducing CO2 and other GHG emissions alone will simply not be enough. What seems to be missed so often, by scientists and lay people alike, is that the key factor of anthropogenic climate change arises as a result of the increased heat of the Earth’s surface caused by our land-management practices.
The state of our land changes how heat is absorbed, emitted and processed, and consequently how heat affects atmospheric processes. Poor land management is the cause of excess heat, and GHGs trap and hold that heat. Sitting beneath it all, is soil. Soil plays a critical role in regulating the earth’s temperature. Soil is vital for life, from the smallest organisms to the planetary climate system. Soil is what holds life as we know it together.
Soil organic matter is 50 percent carbon. Carbon today is often misunderstood and wrongly demonised; it is a primary component of all known life on Earth. By glueing soil together, organic matter provides a home for microorganisms, feeds both micro– and macro–organisms, stores nutrients, resists pH change, and performs many other critical functions. On the macro scale, aerated organic–matter–rich soils protected by vegetation, propagate rainfall into the interior of continents. Soil provides the structure that underpins landscape resilience, and sick soil is a key and under-recognised aspect of climate change.
Through science the key role soil, land and landscape play in regulating our climate is increasingly being recognised in practices such as conservation agriculture, regenerative agriculture and natural-sequence farming. These land–management practices have demonstrated that it is possible to restore degraded land and in so doing restore the small water cycle (when water which evaporates over land returns to the same land in the form of precipitation; locally derived rain). However, the connection between soil as a key environmental function and climate change is less well known and understood.
Soil provides the structure that underpins landscape resilience, but the health of the soil beneath our feet is not obvious, and this lack of awareness results in management practices which degrade soil. Degraded soil drastically increases infrared radiation, a primary driver of climate change. Soil health also has a critical impact on precipitation, as degrading soil health diminishes the small water cycle.
Climate change is initially and almost primarily controlled by loss of precipitation from continents. As such, global temperature rise is an inadequate measurement of climate change. Our research suggests measurement of precipitation loss predates agreed measurable global temperature increase by at least 20 to 30 years.
We at Carbon Count have made it our mission to regenerate landscape and thereby reverse anthropogenic climate change and reinvigorate agricultural communities through soil carbon farming practices. If you would like to find out more about the power of soil carbon sequestration or would like to understand whether your land is suitable for a soil carbon project, reach out and someone from our team will be in touch.
Postscript: A book shop release of Phil’s and Freya’s book is due out later this year.