Developing countries like China are justified in waiting to combat greenhouse gas emissions until developed nations like the United States take a more active role toward solving the problem, said former US Vice President Al Gore at a conference in Madrid Wednesday, AP reported. Gore questioned how industrialized countries that have contributed to global warming for decades can expect poorer nations to clean up their industries before they actively contribute solutions. His comments come after Beijing reacted to a United Nations report last week with warnings about global warming by saying that China would only act after more industrialized nations do so.