By Dr Ian Clarke
The African continent is suffering severe effects of global warming, though it has been responsible for only a tiny amount of carbon dioxide emissions.
The recent floods in Libya have claimed the lives of tens of thousands, desertification of the Sahel has resulted in large numbers of people being thrown out of their livelihoods and drowning while crossing the Mediterranean in a desperate attempt to find work in Europe.
Global warming is caused by too much carbon dioxide entering the atmosphere as the result of burning fossil fuels, yet it is naturally taken out of the atmosphere in the process of photosynthesis by every green plant in the world. The problem is that we are out of balance because we have not looked after our environment.
The destruction of forests and increased desertification results in decreased removal of carbon dioxide at a global level because deserts do not have any green plants. One of the reasons I am into farming is to do something that has a positive impact on the environment.
Trees are particularly good at removing carbon dioxide, which is why cutting down ancient forests in Uganda is so sad and why the National Forestry Authority has a lot to answer for. Cutting down trees, overgrazing, overcultivation and erosion result in land degradation, but the process can be reversed by farming methods which increase tree cover and put back carbon into the soil, causing carbon sequestration.
This improves the microbiome and water holding capacity of the soil, resulting in increased fertility, which promotes the growth of more healthy green plants.
Some farmers, like myself, have planted fast-growing trees such as pine and eucalyptus to be used for electricity poles and timber. While these trees take carbon out of the atmosphere, it all goes back in again if they are used as firewood or burned as charcoal.
If they are turned into electricity poles, they will store the carbon for a few years until the pole decays. However, if charcoal itself is not burned but activated by soaking in liquid manure containing nitrogen, it can be added back to the soil as biochar in a process which sequesters carbon for hundreds of years.
Unfortunately, the normal method we use for making charcoal in Uganda also releases dirty greenhouse gases, but there are cleaner ways of making biochar, using a retort.
If you visit my farm, you may find me standing on a pile of compost trying to figure out how to make biochar and compost on a large scale.
Compost can be made from almost anything, including wood chippings, paper, food waste, manure, coffee husks, pulp and vegetative farm waste. It all gets mixed together and heats up to about 60OC, which kills off the harmful organisms. It then forms a rich organic mass which can be put back on the soil to improve its organic content and texture.
The activated charcoal (biochar) has a huge surface area and forms an excellent structure for micro-organisms to thrive for the benefit of plants and fungi.
Coffee is a tree – which therefore uses photosynthesis and takes carbon dioxide out of the atmosphere – so growing coffee makes a positive contribution to reduction in carbon dioxide, but using artificial fertiliser has a negative effect because it is derived from petrochemicals.
Therefore, if we can reduce the use of artificial fertilisers by using organic ones, plus increase the planting of shade trees in the coffee itself, we could make the production of coffee carbon negative, thus contributing to the decrease of greenhouse gases.
Every day, I see topsoil being washed down into rivers and streams because farmers cultivate right to the edge of the river. I see hills being denuded of topsoil because of erosion, leaving bare rock, and we all witness the devastating effects of flash floods and mudslides.
This is happening because of the lack of education of peasant farmers and the rapid increase in the population, with pressure on cultivating marginal land.
If we improve the soil quality, increase tree cover and prevent erosion, we will be preventing the slide into degradation and desertification.
We are far from immune to climate change in Uganda, but as well as playing the victim and asking for reparations from the nations and corporations that caused climate change (which I am also in favour of), we can take positive action. We can demonstrate good practices in productive agriculture and land management, we can produce climate-friendly coffee and get paid not only for the coffee, but for the carbon we are sequestering back into the soils. Some people call this carbon farming.