Climate change has been described as our time's "greatest moral challenge." While the causes and effects of climate change are now well understood, little attention has been paid to the ethical difficulties that climate change poses, or to how human cultures' values, beliefs, and ethics motivate the much behaviour that contribute to climate change. Nor has much thought been devoted to the efficacy or ineffectiveness of measures aimed at mitigating or adapting to climate change. Climate ethics is a field of study that investigates the ethical aspects of climate change (commonly known as global warming) and notions like climate justice. Many believe that ethical issues raised by human-induced climate change have not been adequately addressed in climate change policy debates or in the scientific and economic literature on climate change, and that as a result, ethical issues are being overlooked or obscured in climate negotiations, policies, and discussions. It has been noted that individuals most responsible for climate change are not necessarily the same people who are most vulnerable to its consequences. Climate justice and ecological justice ('eco justice') are terms that are used around the world and have been embraced by a number of organisations.