The environmental sustainability problem has proven difficult to solve. The modern environmental movement has attempted to solve the problem in a large variety of ways. But little progress has been made, as shown by severe ecological footprint overshoot and lack of sufficient progress on the climate change problem. Something within the human system is preventing change to a sustainable mode of behavior. That system trait is systemic change resistance. Change resistance is also known as organizational resistance, barriers to change, or policy resistance. Overview of resistance to solving the sustainability problem While environmentalism had long been a minor force in political change, the movement strengthened significantly in the 1970s with the first Earth Day in 1970, in which over 20 million people participated, with publication of The Limits to Growth in 1972, and with the first United Nations Conference on the Human Environment in Stockholm in 1972. Early expectations the problem could be solved ran high. 114 out of 132 members of the United Nations attended the Stockholm conference. The conference was widely seen at the time as a harbinger of success: "Many believe the most important result of the conference was the precedent it set for international cooperation in addressing environmental degradation. The nations attending agreed they shared responsibility for the quality of the environment, particularly the oceans and the atmosphere, and they signed a declaration of principles, after extensive negotiations, concerning their obligations. The conference also approved an environmental fund and an 'action program,' which involved 200 specific recommendations for addressing such problems as global climate change, marine pollution, population growth, the dumping of toxic wastes, and the preservation of biodiversity. A permanent environment unit was established for coordinating these and other international efforts. [This later became] the United Nations Environmental Program [which was] was formally approved by the General Assembly later that same year and its base established in Nairobi, Kenya. This organization not only coordinated action but monitored research, collecting and disseminating information, and it has played an ongoing role in international negotiations about environmental issues. "The conference in Stockholm accomplished almost everything the preparatory committed had planned. It was widely considered successful, and many observers were almost euphoric about the extent of agreement." However, despite the work of a worldwide environmental movement, many national environmental protection agencies, creation of the United Nations Environment Programme, and many international environmental treaties, the sustainability problem continues to grow