* *控制因素是一个因素,作为其他人的原因。* *反应性因素,而结果:* *反应控制因素。例如,太阳当然是一个控制因素。没有我们做会发生什么影响太阳,但太阳也强烈地影响着我们。幸运的是,它的总输出功率很稳定所以就气候而言,我们不需要担心太多。公司₂既是控制和反应性的因素。我们公司₂添加到大气中,所以我们排放的CO浓度₂反应(活性因子)。但公司₂水平也是一个原因。如果你要做一个简单的气候模型,你将在公司₂浓度固定值或者一个增值作为时间的函数:在这样的一个模型,这将是一个边界条件。如果你做了一个模型,一个工厂或汽车和模拟燃料循环的变化将如何影响公司₂排放,那么这将是一个活性的因素。 It all depends on the context. For H₂O, however, it makes no sense to put in a fixed version as a boundary condition. Its concentration varies rapidly on short timescales: today may be dry and tomorrow a wet airmass may get in. Of course, physically, H₂O causes even more of the greenhouse effect than CO₂, but the increase of H₂O is not what is *causing* anthropogenic climate change; if anything, an increase in H₂O is one of the effects. So, think of it as a system: you add CO₂ (cause), many things happen, including an increase in H₂O in some places (effect). The cause is the *controlling factor*. The effect is the *reactive factor*, even though physically, both CO₂ and H₂O are strongly contributing greenhouse gases.