Global warming is generally recognized as one of the major environmental challenges we have to face in the near future. The students in school today are the ones that will have to deal with the consequences of it tomorrow. That is why education about it is so important. Previous research shows that students believe that environmental issues in general are important problems to be solved. I this study I tested students in grade twelve, in four different schools in order to find out what their level of knowledge about global warming is, how worried they are about it and if there are any correlation between their knowledge and their level of worry. The results show that the students have a medium to low degree of knowledge. They are quite worried except for when it comes to how they themselves will be affected. The correlation between knowledge and worry also indicates that a low level of knowledge is correlated to a low level of worry.