Targets for Stabilization of Atmospheric CO_2

摘要

The United Nations Framework Convention on Climate Change (1) calk for a "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system." However, the required level is still unclear. There are two main reasons. First, the climatological, ecological, and social impacts associated with any given level of atmospheric CO_2 concentration are still uncertain; the equilibrium impact on global temperature of a doubling of the CO_2 concentration alone is estimated by the Intergovernmental Panel on Climate Change (IPCC) to have an uncertainty .range of (at least) 1.5° to 4.5°C (2). Second, even if impacts were known with 100% certainty; the concept of dangerous interference is ultimately a question of value judgments that can only be settled in the political arena.