This paper presents the data from a current study involving 41 Romanian secondary science teachers and a previously published study that compared 89 Spanish and 42 US secondary science teachers. All three groups were convenience samples who answered a two part questionnaire that was given in English, Spanish or Romanian, depending on the sample. The overriding question was whether citizens in countries that have different environmental experiences perceive threats to the biosphere differently and teach about different environmental problems/threats in science classes if at all. Five specific research questions were addressed including the following two: 1) What were some of technological and environmental problems and or threats that were discussed in the 2002 Johannesburg Earth Summit? 2) Can you describe any reasons why you do or do not teach about environmental and technological problems and or threats in your science classes? The results indicated considerable differences in the three nationalities perceptions of and understanding of threats to the biosphere. Perhaps the most important conclusions were: First, perceptions of environmental threats are based to a large degree on citizens personal experiences with the threat/s in the environment in which they live even when those threats may not be the most urgent global threats; and second, if all citizens, no matter where they live, are to become better informed about global threats to the biosphere faced by the world as a whole, there must be a common global science curriculum that addresses these threats.