How will a warmer, dryer climate and higher levels of CO2 in the atmosphere change grassland vegetation and production? Experimental studies which involved the manipulation of main climate change variables in mid-altitude permanent grassland showed that the beneficial effect on grassland production only lasted 1 to 2 years. Submitted to a heat wave, grassland production decreased over a period of 2 years without any significant change in functional composition. Another approach, based on comparing the proportion of forage grass with a nutrient uptake strategy in 861 permanent grassland fields, showed that this proportion increased at the detriment of less productive plants after moderate climate change, regardless of higher CO2 levels. Further long-term experimental studies are required for better understanding and evaluating grassland resilience and its capacity to provide services.