The human-environment system presented shows the effect that a technology such as biogas use has on the social system and the eco system.  This system perspective is a very useful way to learn about all of the interactions that occur as a result of a chance such as biogas fuel.  Each arrow shown has an impact on the topic that it points to.  There are a few feedback loops shown in the systems such as the one that shows that increased education increases technology and increased technology increases the amount of time available for education.  As for Marten’s human-environment system, many of the same subjects are discussed.  For example, farms create animal dung which is then used in biogas generators and then used as compost back on the farms.  However there are clear differences in the social system.  Whereas Marten’s focuses largely on human population, mine focuses more on quality of life such as education, livelihood, and health.  Similarly, Marten’s system presentation discusses broader concepts such as irrigation water on the ecosystem side.  Therefore it is possible to have similarities and differences despite having the same topic because different viewpoints exist.  Therefore even factual evidence can be portrayed differently depending on the author and thus it is important to get multiple viewpoints for the same subject.