Researchers have uncovered a surprising connection between extreme El Niño events and short-term fluctuations in atmospheric CO₂ levels, challenging previous assumptions about the relationship between CO₂ and tropical temperatures.
The Mysteries of the Carbon Cycle Explained
The global carbon cycle is a complex but finely tuned system that helps to control Earth’s climate. The complex relationship between atmospheric CO₂ levels and temperature in the tropics has been a mystery to researchers for decades.
Earlier research had suggested the growing swings in worldwide carbon storage detected in the 1980s and 1990s were due to systematic changes within the carbon cycle resulting from climate change. The latest findings from scientists at the Max Planck Institute for Biogeochemistry and Leipzig University offers an alternative explanation to this decline: severe El Niño events.
El Niño’s Effect On CO₂ Levels Wow
El Niño is the warming of the central to eastern Pacific Ocean, that occurs on average every 2-7 years and can have far-reaching effects on weather patterns around the world. The researchers concluded that increases in temperature throughout the tropical troposphere coincided with increased frequency of extreme El Niño events, a correlation that led to a more than twofold increase in atmospheric CO₂ content per unit temperature rise over previous generations.
That’s because an El Niño event leads to persistent droughts and heat waves in the tropics, which suppresses vegetation growth there, leading to an overall decrease in the amount of carbon taken up by land ecosystems. Indeed, vegetation can even add carbon to the atmosphere that under normal conditions would cover in the soil or forest during El Niño events. This carbon bomb creates the variation in global levels of CO₂ that can be seen.
Conclusion
These fresh results underscore how incorrect — and in some cases upwards of 100% too high — previous climate models are when it comes to the human impact on these pathways, new understanding that is essential for predicting the planet’s future carbon cycle response to climate change. Twigg will, “use them to improve our understanding of how apparently localised processes such as a strong El Nino can have significant global impacts on atmospheric CO₂ and hence climate (via providing more comprehensive real-world data for testing Earth system models). It is knowledge which we need to know as only so can we continue in our battle against climate change and save our planet for the future.
