Climate change

摘要

In "Just Say No to Greenhouse Gas Emissions" (Issues, Winter 2000-01), Frank N. Laird clearly describes political obstacles, implementation problems, and other difficulties associated with the emissions targets and deadlines in the Kyoto Protocol. Focusing on targets and deadlines, however, introduces fundamental conceptual fallacies in addition to those he discusses. The intricacies of the natural world and the complexity of its interaction with human behavior make full specification of a given "state" or "condition" of the Earth system virtually impossible. Contributions from and consequences for some components must necessarily be omitted in any finite characterization. Furthermore, evidence shows that in prehistoric times, the Earth system exhibited both much higher atmospheric concentrations of carbon dioxide and breathtak-ingly rapid climate change. Designating a particular atmospheric concentration (or rate of annual emissions) of greenhouse gases to be "acceptable" is doubly dicey because doing so both oversimplifies the complex dynamics involved and relies on a simplistic notion of the consequences of climate change.