Objective of this work is to explain the ecological crises in detail. As the phenomenon, the ecological crises can be observed from many points of view and there is no universal answer. We can explain it only if we consider all those different views. Through chapters, themes, facts and personal views about the topic, ecological crises is exposed, with the consideration of readers ability to create the clear image of causes, issues, consequences and possible crises solutions. Whenever it was appropriate, I tried to explain the key words on which theme correspond to make this work legible. Sociological review observe the crisis as phenomenon which appeared in the period of the Industrial revolutions. Within the philosophical review I introduced the reader to the beginnings of the ecological philosophical thoughts, called deep ecology movement. Bioethics principles are elaborated as they are contained in every form of sustainable development. Economical review explains world's ethos and how economical collapse is direct cause to many more devastating crises forms. The Chapter Ecological crises without man tries to determine whether an ecological crisis on Earth is possible without human cause or even within human absence, so I explained the notion of crisis in order to determine whether it occurs in other life groups as well. This chapter was created by critical reflection and as a reaction to existing professional theses. I took the Age of Ice and the catastrophe caused by an asteroid impact as an example. Sustainable development as an orientation development of society and a striking plan of the global level is a direct link to the ecological crisis, as plan is reaction to crises. Finally, I used the acquired knowledge to review the Republic of Croatia in the context of the ecological crisis and sustainable development. I tried to list the possible causes of the crisis as well as the ways of the state leadership in creating a responsible country. I observed the Republic of Croatia through the ecological situation and action, before and after accession to the European Union. I particularly emphasized the Fund for Environmental Protection and Energy Efficiency (EPEEF) because I used their example of the practical implementation of current environmental actions.