Global vegetation biomass production efficiency constrained by models and observations

Area of Science:

• Ecology
• Biogeochemistry
• Climate Science

Background:

• Plants convert only a portion of photosynthesized carbon into biomass.
• Understanding biomass production efficiency (BPE) is crucial for accurate carbon cycle modeling.
• Current estimates of BPE and its global variation are limited.

Purpose of the Study:

• To provide a new global estimation of BPE.
• To assess the accuracy of carbon cycle models in estimating BPE.
• To refine estimates of global carbon turnover and sinks.

Main Methods:

• Combined field measurements from 113 sites with data from 14 carbon cycle models.
• Calculated BPE as the ratio of biomass production to photosynthesis.
• Quantified global biomass production for non-cropland ecosystems.

Main Results:

• Global BPE is estimated at 0.41 ± 0.05, with boreal forests (0.48) higher than tropical forests (0.40).
• Carbon cycle models tend to overestimate BPE by 24%, with models including carbon-nitrogen interactions showing more realistic results.
• Correcting model bias reduced estimated global ecosystem carbon storage change over the last century by 67%.

Conclusions:

• BPE varies significantly across biomes, impacting carbon sink estimations.
• Carbon cycle models require refinement to accurately represent BPE and carbon storage.
• This research improves our understanding of the terrestrial carbon budget and its response to climate change.