There are three huge carbon reservoirs – the earth (soils), the oceans, and the atmosphere. The first has been dangerously depleted, the second and third overloaded. How do we move the carbon back to where it ought to be? How do we bring the carbon home?
Most of Drawdown is not about drawing down the atmospheric carbon at all – it is about reducing emissions so it doesn’t build up further. But while twenty years ago that would have saved us, now it won’t. We do actually have to draw the carbon down, back into the earth.
Pat has referred in her last blog http://www.ourclimatedeclaration.org.nz/re_reading_drawdown to the truly horrible ideas that have been suggested for geo-engineering – stopping more carbon build up so some can continue to burn their coal and oil and we don’t have to change anything. They are generally very dangerous – blocking sunlight permanently, so our grandchildren will never experience a truly blue sky and golden sunlight. Capturing carbon from emissions from power plants and taking them by pipeline to where they can be pumped into old gas wells where they might stay??? Maybe?? Changing the chemistry of the oceans. Drawdown rightly rejects these.
But nature has provided us with a genuine path to drawdown through photosynthesis and soil building. Everyone knows that to “offset” your emissions you plant a tree. There’s not much discussion about who will tend it and what will happen to it in the long term. It certainly doesn’t offset further fossil fuel emissions – those have to stop, as well as drawing down some of the carbon we have put there in the last few decades.
It’s not widely known that much more carbon can be stored in soils than in forests – below the ground rather than above it. As a society we don’t pay much attention to soils, yet they are the foundation of all life. Their carbon content varies widely but it is estimated that globally, soils have lost 50-70% of their natural carbon. Putting it back is slow and painstaking but has benefits in greatly increased food production, water retention in droughts, healthier crops, more biodiversity.
The people who can mainly do this, of course, are farmers – but there are ways urban people and communities can contribute. Backyard gardens are a great opportunity. But not just any backyard garden.
Carbon is lost to the air whenever soil is exposed, especially in hot sun. So the first principle is cover it. Beds not being used at the moment can grow cover crops – preferably a mixture of nitrogen fixing plants like lupins or peas, with crops that will add a lot of bulk and carbon – oats, buckwheat. It almost doesn’t matter what, as long as it grows fast and covers the ground. Then some time before the next crop is going in, fork it under, or pull and lay flat on the surface and cover with weed mat. It will protect the soil from carbon (and nitrogen) loss while growing, and later compost on or just under the surface. If there isn’t time for a cover crop to grow, cover the soil with something – weedmat works, but long grass or grass clippings as mulch will add fertility at the same time.
The second principle is save yourself some work – don’t dig! Use a fork to loosen the soil and remove weeds, but don’t turn it over. This is the garden equivalent of no-till farming. The worms will love you because the soil profile stays intact – it doesn’t like being upside down. Digging exposes more soil surface to carbon loss into the air.
The third principle is to avoid monocultures. Interplanting, mixtures in the row or alternating rows not only confuse the pests but the plants are harvested at different times and the soil is not left bare.
These are all sustainable farming principles, which can be applied at small scale for home and community gardens.
Well made compost (not just a decaying rubbish heap) will add carbon and the soil will retain water and nutrients longer. Any good organic gardening book will confuse you with the hundreds of ways of making good compost. Don’t be confused – just choose one that suits you and do it!
So community gardening is a prime example of what communities can do to draw down carbon. There are hundreds of ways – a group of families in the same street could plan their gardens together to grow a wider range of vegetables and work them co-operatively. When one household is stressed with exams, sickness, work crises, others takeover what needs to be done.
An apartment block could negotiate with Council to get some vacant land and set up a community garden. There are more than 100 listed at https://organicnz.org.nz/community-gardens-nz/ One of the oldest and best known is Kelmarna in Auckland. Groups of young people could help old people who have gardened sustainably for years, and now can’t handle all the work so are thinking of converting it to lawn. Lawns – now there’s an issue. How much food could be grown and carbon built in soils if lawn deserts were planted? We only need so much space to kick a ball and play golf.
Carbon gardening, like carbon farming, will grow more and better food. Individual backyards are fine, but community backyards and gardens are so much more fun.
Motueka community gardens http://www.motuekaonline.org.nz/community-garden/
Thames Bright Smile Community Garden http://www.cityfarmer.info/wp-content/uploads/2017/12/bajk.jpg