臭氧层破坏ozone layer depletiontransboundary,全球变暖global warming,酸雨acid deposition,热带森林砍伐tropical deforestation,土地荒漠化desertification,在发展中国家的污染问题pollution problems in developing countries,濒危物种(???)endangered species,海洋污染marine pollution,大气污染air pollution,危险废物的越境转移transboundary movement of hazardous wastes。