Governments have responded on paper. For instance, in 1992, at the Earth Summit in Rio de Janeiro, Brazil, representatives of about 150 countries signed a treaty affirming their commitment to reduce greenhouse - gas emissions, particularly carbon dioxide.
लक्ष्य था कि वर्ष २००० तक औद्योगिक राष्ट्रों द्वारा ग्रीनहाउस उत्सर्जन को १९९० के स्तर तक घटा दिया जाएगा ।