biosfeerfeedbacks

Biosfeerfeedbacks are feedback processes in which biological systems modify environmental conditions, which in turn influence biological activity. They are part of Earth system feedbacks that connect living organisms, ecosystems, land surfaces, oceans, the atmosphere, and climate. Biosfeerfeedbacks can be positive or negative and arise from interactions among photosynthesis, respiration, nutrient cycling, water fluxes, and greenhouse gas exchange.

Key mechanisms include carbon cycle feedbacks: plants remove CO2 through photosynthesis, but warming can increase soil and ecosystem respiration, releasing CO2 and potentially accelerating or dampening climate change depending on nutrient and moisture conditions. Nutrient constraints, especially nitrogen and phosphorus, shape the strength and direction of these feedbacks. Hydrological feedbacks involve evapotranspiration and rainfall interception, which influence local climate and vegetation productivity. Albedo changes from shifts in vegetation and snow cover affect the energy balance. Methane and nitrous oxide emissions arise from wetlands, rice systems, enteric fermentation, and thawing permafrost. In the oceans, the biosphere affects carbon uptake via phytoplankton productivity, while warming and changing stratification alter nutrient supply and carbonate chemistry, with consequences for CO2 exchange and ocean acidification.

Examples include deforestation reducing carbon storage and potentially turning forests from carbon sinks to sources, boreal and tropical forest responses to drought and warming, permafrost thaw releasing methane, and phytoplankton community changes altering the ocean carbon sink. These feedbacks interact with human actions such as land-use change, agriculture, and fossil fuel emissions.

Understanding biosfeerfeedbacks is essential for modeling Earth system dynamics. They introduce uncertainty into climate projections and are integrated in many climate models as coupled biosphere–climate components. Recognizing their potential can inform land management, conservation, and climate policy aimed at sustaining ecosystem services and limiting climate risk.