Here we focus on climate impacts, noting first the need to distinguish valid dire climate warnings from breathless scaremongering. Seeking to separate wheat from chaff, we work systematically through the myriad ways in which climate change is expected to impact natural systems including: sea level rise; extreme weather; ocean acidification; ecosystem stress/collapse; water scarcity; and altered global circulations. The resulting human impacts would include: food scarcity; climate migration; health burdens; and heat stress. Predictions in respect of all of these are inherently uncertain and it is therefore difficult to discern how much risk should be acceptable, but it is clear that less risk would be the safer choice.