British oil giant Royal Dutch Shell today is launching an internal market to reduce the company’s carbon emissions, an effort to combat climate change and promote energy efficiency. Under its new tradable emissions permit system, businesses within the Shell group must achieve an annual 2 percent carbon reduction, either by reducing their actual emissions or buying permits from other Shell businesses that are making greater than required reductions. The scheme is intended to help Shell meet its target of cutting greenhouse gas emissions 10 percent from 1990 levels by 2002. BP Amoco had previously introduced a similar system.