Through contribution to the world's longest elevated-CO2 manipulation experiments in situ by Norwegian researchers, it has been shown that environmental effects of elevated CO2 are sustained in the long-term but also display highly complex interactions with other environmental stressors, such as precipitation and temperature. In situ experiments are, and continues to be crucial.
Such studies must, however, be complemented by studies in highly controlled environment where effect of individual factors can be tested, e.g. for CO2). Lazer equipment for continuous monitoring of multiple species of greenhouse gases are now available, as well as monitoring of the entire C cycling in the atmosphere-plant-soil continuum.