A new study from the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) has found that plant nutrient uptake in the deficiency of photosynthesis affects greenhouse gas emissions to the atmosphere.
Using a new global land model they developed and integrated in DOE's Energy Exascale Earth System Model (E3SM), the researchers found that plants can uptake more carbon dioxide and soils lose less nitrous oxide than earlier believed. Their global simulations indicate weaker terrestrial ecosystem reactions with the atmosphere than existing models predict.
Humans have emitted 34 gigatons of CO2 per year, over the past decade. Approximately half of that remains in the atmosphere, while the rest is absorbed by oceans and land (via photosynthesis) while the latter amount, called the terrestrial carbon sink, fluctuates year to year subject to factors such as fires, drought, land use, and weather.
Scientists are trying to understand how growing global carbon dioxide emissions will disturb the terrestrial carbon sink, which is valued to currently be between 0 and 11 gigatons of CO2 per year, including land-use change, with large inter-annual inconsistency. An added hurdle contains terrestrial nitrous oxide, which is a potent greenhouse gas naturally released from land and by agricultural and industrial activities.
They found that a major share of nutrient uptake takes place in the absence of photosynthesis as plants and microbes compete for nutrients.