The sustainability framework extends ethical concern to future generations. Human society now consumes natural resources faster than they can be replenished, and this is compromising the ability of future generations to meet their needs. Current and future generations are inheriting a world that is biologically impoverished, has fewer resources, and suffers from more pollution than ever before. Sustainability challenges present day humans to consider the well-being of future generations, to view their needs as worthy of our moral concern. Modern humans are not accustomed to considering future generations, but the power of our markets and technologies threaten their quality of life. We can express a moral concern for the future by restraining our consumption of non-renewable resources today. Note that some resources, such as minerals, are essentially finite. Other resources, such as wind and plants, because they draw their energy from the sun, can be managed so as to provide a continuous source of goods.