This would respond to our environmental responsibility as researchers and at the same time make experimentation cost effective for longer term research. Our synthesis demonstrates a spatial disparity in eCO2 research that may now open up possibilities for several newly-industrialized countries that host ecosystems of global significance within their borders. However, it should be noted that many tropical regions of Asia and South America are also presently subject to elevated nitrogen (N) deposition rates that are projected to intensify (Dentener, 2006, Boy et al., 2008 and Hietz et al., 2011). Our existing understanding of N × eCO2 interactions remains

relatively limited (only 21 temperate experiments of the 151 eCO2 experiments in our analysis examined N Sirolimus order deposition interactions). However, research in temperate find more forests suggests that elevated N deposition increases carbon sequestration (Thomas et al., 2009). For boreal regions where high-latitude warming is a more significant future priority, further research on interactions between warming and eCO2 is needed, because increased plant productivity could prime old carbon release from the soil via inputs of new carbon. To our knowledge only two high latitude eCO2 experiments have investigated interactions with warming, demonstrating significant eCO2 treatment effects on tree growth

(Kilpeläinen et al., 2005) and mainly temperature effects on above ground growth in sub-arctic dwarf shrubs

(Olsrud et al., 2010). However, the latter study highlighted the effects of CO2 on mycorrhizal colonization but did not consider root growth and belowground C. More widely, other global climate factors, such as changing precipitation levels, may modulate eCO2 responses via influences on plant productivity and soil carbon dynamics, particularly in regions that experience dry conditions. For example, eCO2 induces the accumulation of non-structural carbohydrates in grasses and trees, particularly under drought conditions (Duan et al., 2013 and AbdElgawad et al., 2014). Benzatropine Induction of such compounds and other physiological responses including effects on stomata can improve tree seedling drought survival (O’Brien et al., 2014). eCO2 would therefore alter the capacity of some plant communities to regenerate and withstand drought under changing climatic conditions. A new program of eCO2 research would therefore need to incorporate further relevant climate manipulations where suitable. For industrialized countries that have already undertaken eCO2 experimentation, now is the time to collaborate, to share expertise and to “think globally rather than locally.” The opportunity remains to tackle the outstanding question about eCO2 and plant-mediated carbon dynamics. The following are the supplementary data related to this article. Fig. S1.