This paper provides some considerations on the energetic, environmental and climatic issues of the present time, starting from the knowledge of what has happened in the past. The paper does not intend to be exhaustive, since knowledge and culture, both in their broad meaning and in relation to the specific subject, are continuously developing and many certainties of today may inevitably be further discussed and even objected in the future. The authors agree on the need of gradually shifting from non-renewable to renewable energy sources, but also want to emphasize the valuable contribution given in the last two centuries by fossil fuels to the development of our society, underlining that their replacement cannot occur in short time: such an attempt would lead to shortage of resources for the increasing needs of a still growing world population. The difference between the environmental and the climatic issues will be remarked, highlighting the need to deepen their knowledge to better understand the related events and their causes: this step will be necessary to reliably forecast the future changes and ensure that we will be able to face them by proper actions in due time. From a global prospective of the human society, the necessity to identify some priorities in carrying out suitable actions to tackle the problems of the present time will also be highlighted.