Research brief: El Niño variations have little impact on terrestrial carbon cycle

Different expressions of El Niño do affect interannual variability in the terrestrial carbon cycle. However, the effect over longer timescales is small. This means the changing frequency of these two types of El Niño events may be of little importance in terms of robustly simulating the future terrestrial carbon cycle.

Picture: Ocean sunset. Credit: Pixabay (Pexels).

The El Niño–Southern Oscillation (ENSO) describes changes in the sea surface temperature patterns of the Pacific Ocean. This influences the global weather, impacting vegetation on land. However, there are two types of El Niño: the central Pacific and the eastern Pacific.

CLEX researchers explored the long-term impacts on the carbon balance on land linked to these two El Niño types. Using a dynamic vegetation model, we simulated what would happen if only either a Central Pacific or Easter Pacific El Niño event occurred.

They found that the different expressions of El Niño do affect interannual variability in the terrestrial carbon cycle. However, the effect over longer timescales was small. This means the changing frequency of these two types of El Niño events may be of little importance in terms of robustly simulating the future terrestrial carbon cycle.

Paper: Teckentrup, L., De Kauwe, M. G., Pitman, A. J., and Smith, B.: Examining the sensitivity of the terrestrial carbon cycle to the expression of El Niño, Biogeosciences, 18, 2181–2203, https://doi.org/10.5194/bg-18-2181-2021, 2021.