Listen now | Microbiologist and regenerative agriculture expert, Walter Jehne, on how soil can capture carbon, promote global cooling, and feed billions on very little space. He explains how politics got in the way of progress in the 70s, and why government defence departments are scrambling to speak to him and his team.
Thanks to Rachel and the presenter for the interview and discussions.
The proposal for cooling through boosting transpiration is qualitatively flawed. This cooling mechanism requires significantly increase heating power at the surface to effectively drive it; amplifying the hydrological cycle is a negative feedback mechanism in the event of already severe surface warming. Increasing cloud cover is a second-order negative feedback mechanism on the efficiency of cooling by transpiration.
The discussions lack quantitative rigor. The presenter has not performed an energy and resource requirement calculation to support the engineering feasibility of artificially amplifying the transpiration/precipitation cycle. Energy consumption to source the required freshwater in desiccating regions is beyond what is at our disposal. To increase transpiration by 2 mm/day over 3% of the Earth's surface requires the total power consumption by humanity of 2.7 TW. The cooling from this process is also not enough to fix the total, globally averaged energy imbalance of >3 W/m2 (with respect to preindustrial period).
The rate of carbon fixation through photosynthesis is too slow for climate relevance. Net primary production on land is limited to 40 GtonC per year. It is thus impossible to recapture the ~1000 GtonC already emitted by humans within a decade, even if quadrupling net primary production and converting all of the product to biochar.
I don't recall hearing him mention the proposition to increase evaporation. He does talk about increasing transpiration. I will re-listen again at some point
We have less than 9 years to convert agriculture to store carbon to retain water but we can't even start in any meaningful way until WWIII is over. There are so many elephants stuffed in the room that it is a wonder that anyone can draw a breath to talk about this stuff.
There is no humanly possible solution to the human caused problems. The earth does not need us to save it. It will fix things itself. It has gone through many changes over the last 3.5 billion years and will go successfully through many more in the next 3.5 billion years.
It looks like hyper-intelligence is going to be a massively unsuccessful evolutionary adaptation.
I must admit I struggled a bit with this, and was left with more questions than answers. My understanding about water vapour as a greenhouse gas is that it's powerful but short-lived, and that it is a positive feedback loop to the main (human) cause of global heating, CO2. As the atmosphere warms, it can hold more water vapour, therefore more heating etc.. Also I'm not sure about the idea that if you reduce emissions, the oceans will just give up some of their CO2 to replace them. Even if that was the case, the massive amounts that are being absorbed by the oceans are also causing acidification, making it problematic for creatures that make shells, disrupting the food chain.
I've never heard that you can feed yourself with just 4sq metres of soil, did I mishear that? It sounds very optimistic. A while back you interviewed Andres Jara, who also talked about no-till farming. In the U.K. it's more commonly known as 'no-dig' and it's becoming very popular with vegetable growers. See Charles Dowding, who has some great videos on the technique, and how to build soil with composting.
I think that that your discussions with Walter and Anastassia have really pointed to where our focus needs to fall.
Why re-invent the wheel. Natures systems have been doing a fabulous job of regulating the planet's climate for millennia.
Instead of taking the arrogant 'humans know best, industry and technology will solve our woes' approach, I think it's long overdue for humans to transition to supporting nature's systems to bring us back to a habitable equilibrium.
Thanks to Rachel and the presenter for the interview and discussions.
The proposal for cooling through boosting transpiration is qualitatively flawed. This cooling mechanism requires significantly increase heating power at the surface to effectively drive it; amplifying the hydrological cycle is a negative feedback mechanism in the event of already severe surface warming. Increasing cloud cover is a second-order negative feedback mechanism on the efficiency of cooling by transpiration.
The discussions lack quantitative rigor. The presenter has not performed an energy and resource requirement calculation to support the engineering feasibility of artificially amplifying the transpiration/precipitation cycle. Energy consumption to source the required freshwater in desiccating regions is beyond what is at our disposal. To increase transpiration by 2 mm/day over 3% of the Earth's surface requires the total power consumption by humanity of 2.7 TW. The cooling from this process is also not enough to fix the total, globally averaged energy imbalance of >3 W/m2 (with respect to preindustrial period).
The rate of carbon fixation through photosynthesis is too slow for climate relevance. Net primary production on land is limited to 40 GtonC per year. It is thus impossible to recapture the ~1000 GtonC already emitted by humans within a decade, even if quadrupling net primary production and converting all of the product to biochar.
Hi Ya Tao
I don't recall hearing him mention the proposition to increase evaporation. He does talk about increasing transpiration. I will re-listen again at some point
We have less than 9 years to convert agriculture to store carbon to retain water but we can't even start in any meaningful way until WWIII is over. There are so many elephants stuffed in the room that it is a wonder that anyone can draw a breath to talk about this stuff.
There is no humanly possible solution to the human caused problems. The earth does not need us to save it. It will fix things itself. It has gone through many changes over the last 3.5 billion years and will go successfully through many more in the next 3.5 billion years.
It looks like hyper-intelligence is going to be a massively unsuccessful evolutionary adaptation.
I must admit I struggled a bit with this, and was left with more questions than answers. My understanding about water vapour as a greenhouse gas is that it's powerful but short-lived, and that it is a positive feedback loop to the main (human) cause of global heating, CO2. As the atmosphere warms, it can hold more water vapour, therefore more heating etc.. Also I'm not sure about the idea that if you reduce emissions, the oceans will just give up some of their CO2 to replace them. Even if that was the case, the massive amounts that are being absorbed by the oceans are also causing acidification, making it problematic for creatures that make shells, disrupting the food chain.
I've never heard that you can feed yourself with just 4sq metres of soil, did I mishear that? It sounds very optimistic. A while back you interviewed Andres Jara, who also talked about no-till farming. In the U.K. it's more commonly known as 'no-dig' and it's becoming very popular with vegetable growers. See Charles Dowding, who has some great videos on the technique, and how to build soil with composting.
I think that that your discussions with Walter and Anastassia have really pointed to where our focus needs to fall.
Why re-invent the wheel. Natures systems have been doing a fabulous job of regulating the planet's climate for millennia.
Instead of taking the arrogant 'humans know best, industry and technology will solve our woes' approach, I think it's long overdue for humans to transition to supporting nature's systems to bring us back to a habitable equilibrium.