Norway's agricultural emissions have declined, but the reasons are interesting.Learn more »
The Solution to the Entire Climate Problem?
We'd all like to wake up one day and hear that someone has come up with the answer: someone can fix the climate problem without us having to lift a finger! We can carry on exactly as we were before, shuffling billions of tonnes of fossilised carbon into the atmosphere every year, cutting down rainforests, and eating our t-bone steaks, without a care, because someone found the switch that makes everything all right. We just need to flick that switch!
For a lot of people watching a recent TED talk, that marvellous vision seems to have come to pass. That TED talk was about 'holistic management', a specific, managed form of agriculture that aims to work in harmony with nature. The claim, made in the TED talk by Allan Savory, a long-standing proponent of this form of agriculture, is that if we apply this method of grazing cattle and sheep across the world's grasslands, then we could remove carbon from the atmosphere sufficient not only to offset the substantial annual emissions from livestock production, indeed, not only to offset all man-made emissions of all greenhouse gases every year, but in fact to take enough carbon dioxide out of the atmosphere to undo all our emissions since pre-industrial times and return the atmosphere back to natural levels of CO2.
Down from 400 ppm today to 280 ppm in under 40 years. Problem solved. Just graze more livestock and do it according to our designs.
There may well be many benefits to holistic management, and I have no desire to address those here. But when the claim is made that we can solve one of the greatest crises humanity faces with no change in our lifestyles, a king of magic cure, then that claim cannot be taken at face value.
The carbon that we have transferred to the atmosphere in the last few decades took many millions of years of natural processes to store underground in the first place. Now if we tweak nature then we can put it all back again in less than 40 years. Nature is mighty, but only if we harness it properly.
The TED talk in which Savory made this extraordinary claim has now been watched over 4 million times. And why not? It's inspiring, like many TED talks.
The claim can be broken down into two components. First, how much carbon could carefully managed grazing withdraw from the atmosphere and store in the soil? Second, how would that compare against how much carbon we've added, and continue to add, to the atmosphere? These are detailed in the Savory Institute's recent report "Restoring the Climate".
The Savory Institute claims in that report that holistic management, applied to 5 billion hectares of the world's grasslands (one-third of the Earth's land area) would absorb 45 billion tonnes of carbon dioxide every year from the atmosphere. This claim was recently addressed comprehensively by a report "Grazed and Confused?", written by a team of leading sustainability researchers. Their analysis demonstrated an upper limit of 800 million tonnes, far below that of the Savory Institute, and moreover that this is time-limited: such absorption rates couldn't go on forever as soils reach saturation levels.
But even if it were true that holistic management could absorb 45 billion tonnes of CO2 every year, would that solve our climate problem in under 40 years?
In "Restoring the Climate", the Savory Institute converts this amount of CO2 to a concentration of CO2 in the atmosphere: 6 parts per million (ppm). That is, absorbing 45 billion tonnes of CO2 from the atmosphere, all else equal, would reduce the concentration in the atmosphere by 6 ppm. They then say that our current annual carbon emissions are 2.5 ppm/year.
And there we spot a problem. Our emissions of CO2 (setting aside other greenhouse gases) are about 40 billion tonnes per year, which is equivalent to a little over 5 ppm/year. The reason for the difference? About half of our emissions every year are absorbed by the oceans and land systems already. The oceans absorbing CO2 is why we face ocean acidification.
Why does this create a problem for the maths? If we suddenly absorb large amounts of CO2 from the atmosphere then the disequilibrium that exists will flip and the oceans and land systems will become sources of emissions instead of sinks.
The reason oceans are absorbing vast quantities of our carbon emissions is because we have created an imbalance. A ball will roll down a sloping floor. Lightning releases built-up electrical tension. So too will oceans absorb CO2 molecules if the concentration difference is sufficiently high.
If we reduce the carbon dioxide in the atmosphere sufficiently then we switch this imbalances the other way and oceans will start to release carbon dioxide back into the atmosphere. So not only will oceans stop helping us, they'll start making it hard for us.
According to a study by Long Cao and Ken Caldeira, if we magically removed enough CO2 from the atmosphere to take it back to pre-industrial levels, then the oceans and land will release vast quantities of stored CO2.
If we ignore this intervention by the oceans and land systems in our affairs and rather assume only that they will no longer either help or hinder our carbon experiments, then what does the math look like?
In that case, removing 6 ppm/yr from an atmosphere currently at about 405 ppm, and fighting against continuing emissions of just over 5 ppm/yr (from transport, energy systems, etc.), would take almost 200 years.
Adding in the release of carbon from oceans and land systems could easily add many decades to that.
But all of this is rather academic given that holistic management cannot absorb the mammoth quantities of CO2 that it claims. The silver bullet has become a pea shooter.
I note in passing that the Savory Institute's report itself seems caught between bold optimism and cautious caveat. Immediately after presenting their case for saving the world, the authors write: "How realistic these numbers are is unknown, since the bases for them have yet to be tested." An apparent editorial oversight means they have two versions of the closing sentences in this section, leaving us either with the circumspect "potential may indeed be promising" or the very bold "potential is extremely promising while providing no negative consequences, but instead many opportunities."
Climate policy cannot be based on such faulty analyses. Nor should we be presenting the public the false message that more livestock will solve problems we have created by our own excesses, when in fact we probably need fewer livestock.
Believing in a silver bullet is the opposite of holistic thinking.
The Paris Agreement has finally paved the way for global CO2 mitigation. But each country has a different route, and how much progress are they making? Glen Peters and colleagues suggest a framework of analysis.Learn more »
The Global Carbon Project has released its 2016 edition of the world’s carbon budget, including historical emissions by country back to 1751. This multidisciplinary and international effort provides a set of consistent supporting data for further analysis.Learn more »