A multi-biome gap in understanding of crop and ecosystem responses to elevated CO2

A key finding from elevated [CO2] field experiments is that the impact of elevated [CO2] on plant and ecosystem function is highly dependent upon other environmental conditions, namely temperature and the availability of nutrients and soil moisture. In addition, there is significant variation in the response to elevated [CO2] among plant functional types, species and crop varieties. However, experimental data on plant and ecosystem responses to elevated [CO2] are strongly biased to economically and ecologically important systems in the temperate zone. There is a multi-biome gap in experimental data that is most severe in the tropics and subtropics, but also includes high latitudes. Physiological understanding of the environmental conditions and species found at high and low latitudes suggest they may respond differently to elevated [CO2] than well-studied temperate systems. Addressing this knowledge gap should be a high priority as it is vital to understanding 21st century food supply and ecosystem feedbacks on climate change.

► Response of plants to elevated [CO2] is dependent upon other environmental conditions.
► There is ecologically and economically important variation in CO2 response within and among species.
► Experimental elevated [CO2] studies have been biased toward temperate species and ecosystems.
► Physiological understanding predicts that tropical species may respond differently to elevated [CO2].
► New studies of elevated CO2 at high and low latitudes are urgently needed.