An important new report from the 颅Intergovernmental Panel on Climate Change states bluntly: 鈥淐limate change is widespread, rapid and intensifying.鈥� 颅Panmao Zhai, the co-chair of the working group that produced the report, said we need 鈥渟trong, rapid, and sustained reductions in 颅greenhouse gas [GHG] emissions, and reaching net zero CO2 emissions.鈥�
There are two ways to achieve net zero: Reduce GHG emissions (principally carbon dioxide, but also methane, nitrous oxides and other gases) or increase the absorption of these gases 鈥� primarily carbon dioxide 鈥� in natural or human-engineered 鈥渟inks.鈥�
In reality, we need both.
Natural sinks are described by the 颅Council of Canadian Academies, currently undertaking an assessment of the potential of sa国际传媒鈥檚 carbon sinks for Environment and Climate Change sa国际传媒, as 鈥渘atural 颅systems 鈥� plants, soils, aquatic and marine environments 鈥� that absorb more carbon from the atmosphere than they release.鈥�
Therein lies their value, and hence their interest for Environment and Climate Change sa国际传媒. What if we could expand the ability of these natural sinks to absorb 颅carbon, keeping it out of the atmosphere?
The problem is that the ability of the main sinks to absorb more carbon is in doubt. In fact, far from the sinks helping us, they may become sources of GHG as a result of human interference, poor management and climate change 鈥� which is itself human-induced.
So as climate change impairs the sinks, it worsens climate change.
One example of this is very apparent in sa国际传媒 and around the word today 鈥� forest fires and other forms of deforestation. Globally, a 2017 study published in Science reported that the world鈥檚 tropical forests are now a source of carbon, primarily due to 颅deforestation and degradation or 颅disturbance of natural forests.
They emitted more than 400 million tonnes of carbon annually, equivalent to about 1,500 million tonnes (or 1.5 billion tonnes) of carbon dioxide. Considering total human emissions of carbon dioxide are about 36 billion tonnes, we can see this is a significant problem.
A paper published last month in Nature, titled 鈥淎mazonia as a carbon source linked to deforestation and climate change,鈥� found that, far from being an important carbon sink, as it once was, the Amazon鈥檚 颅ability to absorb carbon is in decline. In fact, the paper found the Amazon has become a 颅carbon source in its southeastern regions due to 鈥渢he intensification of the dry season and an increase in deforestation.鈥�
Here in sa国际传媒, our forests, which used to be important carbon sinks, are now huge carbon emitters.
In a July 5 article in the National Observer, using data from sa国际传媒鈥檚 official greenhouse gas inventory, Barry Saxifrage found that on average in the 1990s, the forest absorbed 84 MtCO2 (millions of tonnes of carbon dioxide), while on average each year in the 2010s, the forest emitted 39 MtCO2. This large shift, he found, has two main causes: the massive increases in wildfires and, at the same time, a decline in absorption of carbon dioxide via forest growth.
So sa国际传媒 was on average worse off by 123聽MtCO2 annually in the 2010s compared with the 1990s. In fact, in 2018 wildfires led to almost 200 MtCO2 of emissions. 颅Considering that sa国际传媒鈥檚 human-created GHG emissions in 2018 (the latest year for which data is available) were 67.9 of MtCO2, this is obviously a huge problem, and one we must reverse.
Forests are not the only natural sinks where we have problems. Current land use and agricultural practices 鈥� and the 颅high-meat diets that drive them 鈥� make plants and soils major emitters.
But 颅Drawdown, an organization working on carbon reduction, lists 22 different 颅interventions that could make land use a major sink, absorbing many times the amount of carbon we emit today.
But it will require major social changes across many societies, including 颅鈥渆cosystem protection and restoration, improved agriculture practices and prudent use of degraded land鈥� as well as 鈥渞educing food waste and shifting to plant-rich diets.鈥�
If we lose our major sinks 鈥� if they become major sources of GHG emissions 鈥� we are sunk. But if we can mobilize 颅globally and locally to protect and manage our 颅carbon sinks, we might yet manage a smart transition to a net-zero future.
Dr. Trevor Hancock is a retired professor and senior scholar at the University of 颅Victoria鈥檚 School of Public Health and Social Policy.
