By Femi Akinola
A landmark new study has found that, in the last decade, the African Continent has started emitting more carbon than it stores. A group of international researchers made the landmark new study.
The researchers noted that when the total amount of carbon that is requested by natural ecosystems (such as the soil and plants in grasslands, savanas and forests) exceeds the amount of total carbon emissions, within a system, it is referred to as a net sink of carbon.
The new study found that in Africa, as natural ecosystems are converted for agricultural purposes, the carbon storage capacity is decreasing, while the rate of emissions is increasing.
The international research team led by Yolandi Ernst of the University of the Witwatersrand in South Africa, calculated the flows of carbon-dioxide, methane and nitrous oxide through Africa’s terrestrial and acquatic ecosystems to arrived at the conclusion.
According to Yolandi, the research team embarked on the study to know both the amount of greenhouse gases being produced by the African continent and amount being taken up.
She said: ”In this way, we are better able to understand how the continent is contributing to global climate change by releasing greenhouse gases, and how, through taking up the greenhouse gases, it’s helping to mitigate global climate change.
”We collated data from a variety of sources and created models to calculate the amount of carbon-dioxide, methane and nitrous oxide (collectively called greenhouse gases) being released into the atmosphere from several different sources. Some are human sources, like agricultural and fossil fuel emissions. Others sources, like wildfires and termites, are natural.
”Then we calculated the amount of carbon that’s drawn from the atmosphere and stored in what are called carnon sinks: the soils and plants in grassland, savanna and forest ecosystems.”
On the biggest sources of carbon emissions in Africa, Yolandi highlighted the need to distinguish between anthropogenic emissions and natural emissions.
She said fossil fuel burning and agriculture are the biggest sources of carbon emissions in the continent. She noted that both are anthropogenic (caused by humans).
According to her, other emissions are part of the ecosystem functioning but they can also be affected by human activities. ”Examples include fire, methane emissions from herbivores, and inland and coastal water bodies. These all represent quite large emissions, but they are only somwhat affected by human activities,” she emphasized.
Furthermore, she said there are some important natural processes that draw carbon and greenhouse gases back into the land surface. ”These include the growth of vegetation and soil carbon storage, as well as weathering of rocks (which turns atmospheric CO2, into carbonate minerals) and burial of carbons in the ocean.
The previous African carbon budget (1985 -2009) showed the processes drawing carbon into Africa were higher than the natural emissions and the antropogenic emissions. The continent was a carbon sink even though it emitted some anthropogenic greehouse gases.
Globally, the anthropogenic emissions of CO2 are 11.21 gigatons of carbon per year (GtC/yr), but the land takes up about 3.5 GtC/year, slowing the growth rate. the African land sink ai about 0.8 GtC, representing 20% of the world’s total sink.
Yolandi, however, highlighted the fact that the sink capacity hasn’t decreased saying, ” Africa is still taking up just as many greenhouse gases
as it did in the past. The mount of anthropogenic sources has increased so much that the net affect is to be releasing greehouse gases.In short, the continent has become more of a carbon source as it is carbon sink over the study period (2010 – 2019).
What can be done to reverse the trend the international researchers have identified? Yolandi acknowledged the fact that finding ways for Africa to develop in a way that is carbon neutral is a big challenge.
However, she said investment in carbon-neutral energy sources and reducing reliance on fossil fuels would be a better way to start.
