中文摘要：

当前人类活动引起大气中二氧化碳（CO_2）的浓度逐渐升高,地球气候可能将发生不可逆的变化,从目前的冰室气候进入温室气候状态。文中通过对现在地球气候系统与深时温室气候时期的大气CO_2浓度与气候变化临界点、温度与温度梯度、海平面变化与水循环、大洋水体氧化还原状态几个方面进行对比和分析,提出对地球在这种温室气候状态中的气候动力系统的认识亟待提高。尽管深时温室气候并不严格等同于未来地球的气候,但深时时期形成的地质记录为我们提供了全尺度洞察在温室气候状态下地球系统是如何运行的一个天然实验室。

英文摘要：

As the current atmospheric carbon dioxides（CO_2）levels increase rapidly due to human activities,it may approach a critical climate threshold,beyond which Earth may step into a prolonged greenhouse state.In this paper we compile the available records of the atmospheric CO_2 levels,critical climate thresholds,temperature and its latitudinal gradients,sea level change and hydrology,and the oceanic redox state of greenhouse climate in both modern and deep time.We suggest that it is essential to thoroughly understand the climate dynamics in a greenhouse state for predicting Earth＇s immediate future climate.Although the past greenhouse climate may not be an exact analogue of the future climate,the geologic record in deep time offers important insights into how the Earth system responds to warm climates over an extended geologic period.