New study led by PhD candidate Li Na, co-advised by Sebastian Sippel, shows that the doubling of the sensitivity of CO2 growth rate to tropical temperature can be explained by internal climate variability. The trend is explained by the impact of few but strong El-Niño events on land C sink variance

Enhanced global carbon cycle sensitivity to tropical temperature linked to internal climate variability

Doubling sensitivity of atmospheric CO2 to tropical temperature is linked to internal climate variability and El Niño events.

But what does it mean? I have no background in climate science.

Following the positive trend in the 1980s and 1990s, the sensitivity decreased again. Such events are found in by Earth System model simulations with perturbed initial conditions, and do not seem to have an anthropogenic fingerprint.

Thanks for bringing this to our attention. However, I cringe a bit at the terminology selected (in the paper) for the topics discussed.

This is a basic rule associated with potential energy surfaces, if you have shallow minima, variability always moves the system to a new one and the range of variability determines how long it takes.