The Endangered Species Act defines an endangered species as one at risk of extinction “throughout all or a significant portion of its range.” The U.S. Department of the Interior (DOI) has repeatedly defined “significant portion” to mean an area of the range essential to species persistence. This definition is redundant, and various iterations of the definition have been struck down in the past. At the same time, other proposals to list a species only in a portion of its range fail to satisfy the statutory requirements.

The principles of “common but differentiated responsibility” (CBDR) and sustainable development play an integral role in international environmental law. However, these principles have come under fire in recent years, particularly from the global North, which has grown impatient over the lack of contribution on climate change from the emerging economies. Much effort has been expended toward the establishment of greater contribution, and the shouldering of greater responsibility from these countries.

In 1990, when the Clean Air Act (CAA) was last substantially amended, atmospheric carbon dioxide levels stood at about 350 parts per million (ppm). Now they are close to 414 ppm, and the U.S.

In recent years, the drumbeat for more expansive climate-related corporate disclosures has grown louder and more consistent within a broader swath of the financial community. This intensifying call argues for considering more climate-related information legally material under existing U.S. securities disclosure law. A key component of materiality as defined in U.S. securities law—who is a “reasonable investor”—is evolving when it comes to climate-related information. This evolution may soon impact what climate-related information courts consider material.