This paper makes an inventory of the natural capital on earth in terms of exergy, which includes not only renewable and non-renewable energy resources, but also non-fuel minerals. The exergy method is very suitable for the accounting of our natural capital because all kinds of resources can be assessed with a single property. For the case of minerals, exergy allows to unify properties tonnage and grade. Furthermore, the exergy replacement costs of minerals includes additional information of the state of technology. The aggregation capacity of the exergy and exergy replacement cost indicators increases the analysis potential of the results. This way, the non-fuel mineral's wealth can be compared to that of fuel minerals or even to other natural resources. The results of this study reveal that the real scarcity problems that humankind are facing are not based on the lack of energy sources, but on the lack of minerals. (C) 2009 Elsevier Ltd. All rights reserved.