A major goal of the Earth Summit was to:

The major goal of the Earth Summit was to focus on stabilizing the concentrations of greenhouse gases, which aligns with the international recognition of climate change as a pressing global issue. The Earth Summit, held in Rio de Janeiro in 1992, sought to address environmental issues and promote sustainable development through international cooperation. By aiming to stabilize greenhouse gas emissions at 1990 levels, the Summit established a framework for nations to collaboratively work towards reducing emissions and enhancing global environmental health.

This goal tied into broader efforts to confront climate change and its effects, which were becoming increasingly apparent. It laid the groundwork for subsequent agreements, such as the Kyoto Protocol, which aimed for specific national commitments to reduce emissions. The focus on 1990 levels was significant as this was a baseline period acknowledged by many countries, making it a realistic target for international negotiations and efforts.

The other options, while related to environmental goals, do not reflect the primary objectives set forth during the Earth Summit. The Summit was more about cooperation and setting goals rather than punitive measures, which makes the stabilization of greenhouse gases the most accurate representation of its major goal.