Classic theory is described as "early advances of environmental studies from the mid-20th century on," while contemporary theory is defined as "instances that have emerged in the previous few decades in response to both intellectual breakthroughs and the ever-changing reality" in its most basic form (Castree et al. 2018, 3).

While there were some obvious discrepancies between the two theories, I discovered some strong linkages between them as I dug deeper into both ideas, which contradicted my initial preconceptions about classical theory. Initially, I viewed classical theory as an antiquated environmental theory that was no longer applicable to the modern world. However, after comparing many of the classics to contemporary theories, I learned that classical theory is frequently the foundation for current contemporary theories, and that without it, researchers would not have been able to generate new theories and research that I value today. The classic theory of sustainable development, for example, seeks to “see ways of regulating economic growth while optimizing the provision of social welfare and environmental protection...search for innovative ways to fuse relatively unlimited forms of economic growth with wealth redistribution and ecological conservation” (Castree et al. 2018, 110). Not only is the concept of sustainable development still very much alive in today's environmental debate, but it has also served as the foundation for many modern theories, such as earth system science and ecosystem services.