Scientists probably did not adequately convey to the public that their projections for future warming are based on models that account only for the so-called “forced response” in global mean surface temperatures – that is, the change caused by greenhouse-gas emissions. But what is observed at the surface includes unforced, or natural, variations, such as the El Niño and La Niña fluctuations from year to year, and the 60-70 year cycle from the fluctuations of the Great Ocean Conveyor Belt in the Atlantic.
科学家也许并没有让公众充分了解他们对未来变暖程度的预测是基于只考虑了全球平均表面温度的所谓“强制反应”的模型，即由温室气体排放导致的温度变化。但对地表的观察包括了非强制或者说自然的变量，比如年复一年发生的厄尔尼诺和拉尼娜现象以及以60—70年为周期的大西洋大洋传送带（Great Ocean Conveyor Belt）波动循环。