Talks of carbon-related climate change are often limited to CO2, the gaseous form, and greenhouse warming. However, there’s a huge amount of carbon locked inside the ground on which we walk. Experts estimate that soil’s carbon content is more than two-to-three times than that in the atmosphere.
While it’s safely embedded in the ground and helping in the natural process of life, it is not expected to remain there forever. Due to climate change and global warming, the decomposition of organic matter will also accelerate, which means carbon released from the soil will be much higher.
According to a new study published in Nature Communications, if the temperature increases by 2° C (as experts believe it will eventually with the current rate of emissions), approximately 230 billion tonnes of carbon will be released from the soil, all around the globe. For reference, this amount is four times China’s total emission over the last 100 years.
A process called “soil carbon turnover” speed up when carbon spends little time in the soil. It is one of the things classified as “positive feedback” where climate change effects increase other climate change factors. The gaseous CO2 will result in an amplified turnover, which will be increased, becoming worse with fatal additions to the already suffocating planet.
Another similar cycle is permafrost (polar regions) melting. Higher temperature will cause more melting which will release more carbon and methane trapped in the ice and snow for millennia. The repeated cycle will only add to the greenhouse effect and further heat the planet.
According to the team, the soil carbon release mechanism is one of the world’s biggest areas of uncertainty in developing an acute understanding of climate change. To overcome this hurdle, they used a combination of Earth system models (open-sourced software which can simulate climate/carbon cycle to make predictions) with a giant cache of observational data.
“We investigated how soil carbon is related to temperature in different locations on Earth to work out its sensitivity to global warming,” said lead author Rebecca Varney from the University of Exeter. While there is a Paris agreement where countries promise to avoid the dreaded 2o temperature rise, the USA is backing out of the treaty. Even if all countries meet their non-binding targets, some projections estimate global temperatures could still rise by more than 3C, and possibly by over 4C.