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Initial findings

The Tree Council is a national charity which sees itself as a “coalition body for a diverse range of organisations … getting more trees, of the right kind, in the right places; better care for all trees of all ages and inspiring effective action for trees.” In particular they coordinate the national Tree Warden Scheme.

We are lucky to have Tree Warden groups in both Reading and Wokingham. If you want to get involved with local trees in any way, these are early ports of call. The Reading wardens’ Facebook pages reveal an active group, working on planting, care and protection.

The Tree Council is also into hedges and chairs the Hedgelink coalition, which promotes hedgerows. Lacking land to afforest, hedges may play a significant role in Reading’s 2020-25 Climate Strategy.

The other organisations in Reading Tree Wardens’ Useful Links page are worth a look. They include:

• Nature Nurture which seeks to teach children about the natural world. It is based in Reading and appears to be most active here.

• The Woodland Trust, a major charity which plants, protects and restores woodlands on a large scale nationwide. Start looking there if you prefer to fund action rather than take it yourself.

The Conservation Volunteers occasionally run a local tree planting day. though most of their work is other environmental activity. They frequently clear overgrown areas, and this begs the question of what happens to the valuable organic carbon that they clear. We hope that is it captured in some way (biochar, mulch, wooden artefacts, …) rather than sent straight back to the air (burning, rotting, …). Investigation is needed.

Online searches can find many other tree-related organisations, national and international, all eager for donations. One must assess them carefully, particularly on their goals and their capacity to store or preserve carbon in plants and soils.

Is Biochar closer than we think?

I have found a news item about biochar titled Dead Plants are Powering Stockholm. Here’s a key passage:

Stockholm currently has five biochar production facilities working exclusively with green waste gathered within the city. Last year, they predicted that by 2020 it will produce at least 8,000 tons of char per year. That production output will be enough heat to warm 500 homes year round, which may not sound like much until you consider that in doing so they will have also sequestered the amount of carbon equivalent to removing 4,200 cars from the road.

Do read the whole news item. It is an eye-opening introduction to the potential of biochar in municipalities. Stored well in soil, the carbon would not return to air for thousands of years.

The quantities involved are way ahead of what I thought was achievable right now: most unexpected and most welcome. It calls some priorities into question. Are we looking at the best local climate actions?

Biochar is solid carbon, but most climate impacts are measured in terms of carbon dioxide gas (CO₂). Stockholm’s 8,000 tonnes of biochar are equivalent to 29,300 tonnes of CO₂. Reading’s population size is only 17% of Stockholm’s, so our biochar equivalent might be slightly less than 5,000 tonnes of CO₂.

Compare this 5,000 with the 1,200 tonnes of emission reductions from the entire fleet of solar panels in Reading in 2018. We’d need to more than quadruple our solar panels to match biochar Stockholm-style.

Those extra panels would cost about £24 million to install (using an optimistic price of £5000 per UK average domestic solar installation; it was £6800 in Jan 2019). Stockholm invested $11 million = £8.5 million in the biochar facilities. Scaling this pessimistically down to Reading, our biochar production should need £2-3 million, which is within the reach of a community benefit business model.

• Stockholm says it was fortunate to already have a sophisticated green waste collection infrastructure; we have one too.
• Stockholm had to create markets for the biochar; we would too. The types of demand would be similar.
• For the rest we can learn from Stockholm’s experience.

Demands for biochar

Making biochar for the sake of it is not enough to engage anyone except climate activists. (Imagine the reaction: “What?! You want me to BURY fuel?”). There have to be economic or social reasons too. Here are four:

Renewable bioenergy

Biochar production gives off excess heat. Stockholm uses it in a district heating system. It qualifies as bioenergy from a renewable resource. If used as such, further emissions reductions would be added to the calculations above and government subsidies may be available.

In general, any predictably large heat demand would suffice. Its location may influence where biochar production is sited.

A soil amendment

When used in plant beds and fields, biochar improves the soil structure and fertility, and retains nutrients and water, leading to better plant growth. It is fundamental to “the most fertile soil in the world” – the terra preta de índio of Amazonia.

This has positive implications for local food supply. Stockholm gives some biochar free to its citizen gardeners, and sells the rest on the open market to professional growers and to the city’s tree management team, who are reportedly enthusiastic users.

Zero food waste

Biochar is an ideal partner for another municipal waste stream: food waste. In law, human food waste fed to animals is not waste but redistribution. Whether this applies to soil creatures is untested, but stands to reason.

If one ferments food waste using lactobacilli rather than a yeast, the result is a preserve, not edible by humans or vermin but very attractive to soil creatures. None of its food energy, carbon and nutrients are lost, whereas composting loses half or more. After the finished preserve is mixed into soil it is consumed by the soil ecosystem within a very few weeks (much faster than decomposition) producing a rich worm-worked soil, a larger ecosystem, and ultimately more dead organic matter and humus which are stores of carbon.

Biochar addresses a practical problem of lacto-fermentation. This process produces a nutrient-rich liquid which normally requires (a) drainage to avoid drowning the process and (b) capture to avoid losing nutrients. Biochar used as a base layer under the fermentation absorbs the liquid. Thus simpler and cheaper undrained fermentation vessels and methods are possible.

In return, a problem of biochar is solved too. Raw biochar is so absorbent that, at first, it robs nutrients from soil. This hazard typically requires an extra stage in production to pre-charge the biochar from another nutrient source. This is unnecessary with the arrangement described above. The two components, fermented matter and biochar, can be mixed into the soil in one operation – a double boost of food and housing for the soil ecosystem.

Carbon offsets

A carbon offset is a reduction in atmospheric carbon dioxide or other greenhouse gases made in order to compensate for emissions made elsewhere. You can offset your personal emissions by contributing (normally with money) to an offsetting scheme.

Many people shy away from offsetting because some schemes have been found to be scams, with no genuine or permanent carbon reductions involved. It is not easy to judge which schemes are genuine. However, biochar is well suited to carbon offsetting – so well that it ought to be the “gold standard” – for two reasons:

• Biochar in a properly managed store, such as soil under regenerative management, will keep its carbon out of the atmosphere permanently.
• Independent assaying can measure soil biochar content to check the truth of claims.

Solid proof of permanently stored biochar should enable a municipality to seek offsetting status and generate an income stream. The offset price of emitting 1 tonne of CO₂ was 24.36 euros per tonne on 5th Dec 2019, valuing 5,000 tonnes at about £100,000 per year (using our earlier rough estimate of Reading’s potential biochar yield). The level of proof should command a higher price. Hmmm … worth further investigation and estimation. Click here for today’s carbon price.

The UK has lots of great national statistics available online, including “Renewable Electricity Generation by Local Authority”. This means the stats drill down into what is generated in each LA area (not what the LAs are responsible for generating themselves).

The raw numbers of the national statistics are time-consuming to interpret and understand. We wanted to understand Reading and district, so we consumed some of our time to produce a spreadsheet tool. We summarised data for Reading and its neighbouring authorities South Oxfordshire, West Berkshire and Wokingham.

This Is For Everyone

We have opened the tool for general use, as the climate emergency demands. You can choose to look at:

• Any other local authority area in Great Britain, though sadly not in Northern Ireland because the national source data is of poor quality.
• The total renewable electricity generation in each area.
• Each individual type of generation there, such as Photovoltaics (solar panels to you and me), Onshore Wind (turbines) and 10 others.

The spreadsheet is published in Google Sheets so that it should be readable in any decent web browser. You may find it slow to load at first because it must collect a ton of numbers in the background, but it should be fast enough after that. You can’t edit it, except for the input boxes outlined in green.

Have fun.

It is estimated that tight management of refrigerants worldwide can on its own reduce future global heating by half a degree C. For this reason alone it is an early subject for us to study, even though strictly speaking it is not a repair action. Please visit the pages below, initially in the order given.

What is a refrigerant?

Why do refrigerants need management?

How are refrigerants managed?

Community refrigerant management

The horticultural practice at La Ferme du Bec Hellouin in Normandy is of worldwide importance, for both food security and carbon sequestration. To quote from Paris Match (30th August 2018), my translation:

The result is spectacular: from 1,000 square metres of land, Perrine and Charles have a turnover of 55,000 euros. … By way of comparison, conventional organic market gardening makes it possible to achieve an average turnover of around 30,000 euros – from 10,000 square metres. Booom!

… Soil quality has also improved rapidly: a study conducted in 2017 by the University of Liège shows that their soils are storing up to 26 times more organic carbon than the goals set by [the international 4 per 1000 initiative].

… The economic performance of Bec Hellouin farm is based on its ecological performance. The more natural, complex and diverse the farm is, the more productive, sustainable and resilient it becomes.

The farm provided a summary of its method, in French, which is no longer accessible online. For English speakers, my own translation (helped by DeepL.com) is downloadable. Alternatively it is readable in a modular form on this site with a few extra notes and highlighting.

The farm has spawned two books, several academic and governmental studies and an educational establishment on site. The books are:

Hervé-Gruyer, Perrine & Charles (2016). Miraculous Abundance. White River Junction, VT, USA: Chelsea Green Publishing. ISBN 978-1603586429. Translated from the same authors’ (2014) Permaculture : Guérir la terre, nourrir les hommes. Arles, France: Actes Sud Editions. ISBN 978-2330074166.

Hervé-Gruyer, Perrine & Charles (2019). Vivre avec la terre. Arles, France: Actes Sud Editions. ISBN 978-2330119478. This is a magnificent encyclopaedic work, with over 1000 pages in three volumes; one for the ages. A reviewer said he felt he could throw away all his other books on gardening. No doubt an English translation will come, but it will be a major task. Fortunately I read French well enough!