For decades, scientists believed that a significant portion of the carbon stored in the soils of the forests remained protected and practically immune to the effects of global warming. However, long-term research has just cast doubt on that idea.
The discovery arose after one of the most extensive experiments carried out on forest ecosystems. For 37 years, a group of researchers controlled the soil of a forest to heat it to observe how organisms living below the surface responded.
The results surprised even the specialists. They discovered that the microbes began to break down carbon reserves that until now were considered stable, releasing carbon dioxide (CO₂) to the atmosphere and reinforcing a process that could accelerate climate change.
The authors of the work maintain that this mechanism had not been fully incorporated into current climate models and that it could modify projections about the future behavior of the planet.
An experiment that lasted almost four decades
The research was carried out in the Harvard Foresta forest of about 1,600 hectares located in the state of Massachusetts, United States. There, scientists installed a network of underground cables that steadily raised the soil temperature by five degrees Celsius above natural values.
The objective was to reproduce the effects that global warming could generate on terrestrial ecosystems and study long-term soil evolution.
The work was directed by Jerry Melilloresearcher of Marine Biological Laboratory, who followed the evolution of the heated plots for 37 years.
What the researchers discovered
During the fourth decade of the experiment an unexpected phenomenon appeared. Microbes began to degrade stable forms of organic matter that previously seemed resistant to rising temperatures.
That process released carbon that had been stored for long periods in the soil, increasing the amount of carbon dioxide that can return to the atmosphere.
The researchers explained that microorganisms play an essential role because they decompose organic matter and recycle nutrients for plants. However, when temperatures rise steadily, those communities also change and accelerate carbon loss.
Why the discovery worries scientists
The planet’s soils store around 3.5 trillion metric tons of carbon, an amount much higher than what is present in the atmosphere. Until now, it was thought that a good part of these deep reserves remained protected from microbial activity.
The study shows that this carbon can also be released if the climate change It continues for decades, generating a feedback loop: the higher the temperature, the greater the release of CO₂, and the more carbon dioxide that reaches the atmosphere, the more global warming intensifies.
Researchers believe that incorporating this process into climate models will allow for more accurate projections of climate evolution in the coming decades. In addition, they recalled that reducing greenhouse gas emissions and stopping deforestation continues to be one of the main tools to limit the increase in global temperature.
