Methane, carbon and planetary cooling

Walter Jehne
Walter Jehne (Image from ABC Rural)

Its vital that we better understand the dynamics of methane and water in climate change processes. Walter Jehne, former CSIRO Microbiologist and Climate Scientist, and founder of Healthy Soils Australia has some significant insights into the dynamics of climate change. His core message is about the absolute importance of regenerating soils, often referred by him as the sponge. Directly relevant to to soil quality is the oxidation of methane and the potential to cool the planet by enhancing hydrological cycles.

Here is a long video of Walter addressing a group at Harvard University.

At about 1 hour 15, he starts to talk about methane. He claims actively growing pasture generates 100 times more water vapour through transpiration than required, to oxidise methane. The brief video below animates the process, but Walter’s explanation is far more entertaining. Walter claims that the radical increase in methane concentrations results from human industrial activity and says some concerning things about the possibility of large methane eruptions in the artic (no spoilers here – I encourage you to watch his video).

Regenerating soils

We know that regenerating soil by enhancing soil organic matter has multiple benefits. First, it halts the losses generated by intensive agriculture. According to Walter Jehne:

…our high input agriculture often loses 5-10 tonnes of carbon per hectare per year (tC/ha/an) from soils, as well as the embodied emissions from inputs. (from Regenerate Earth)

The carbon returned to the soil enhances hydrological flows. Every gram of carbon added can retain eight grams of water. Thus the resilience of vegetation is enhanced. The resulting additional transpiration provides a latent heat sink to cool the atmosphere. Unfortunately by removing the quantities of vegetation we have dramatically reduced this cooling potential. Improving levels of soil carbon and promoting revegetation will help to cool the planet!

The process is to reverse the ratio of carbon oxidation to bio-sequestration, in order to regenerate the resilience and hydrology of the soil carbon sponge. We can do this via our management of our soils and landscapes. (from Regenerate Earth)

Ruminant animals have an important role in this process as they recycle fertility and encourage the regrowth of pastures. Fortunately the Minister of Climate Change, James Shaw, has recognised the tension in the debate about methane and proposes removing it it from emission equations.

We are by no means out of the woods yet, but Walter Jehne’s insights are encouraging (and scary at the same time if we don’t act). On page 3 of Regenerate Earth he provides wise advise to stop waiting for more research and take collective action.

While there will always be more to know, after 60 years and US $60 billion already spent on IPCC research, we know enough of what we need to do. What we need to know now, may be learnt best by doing it.

And thanks to the indomitable Max Purnell for bringing this to my attention.

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