总的来说,任何个人代理不是一个可靠指标。combindation多个代理,提供了一个清晰的图像。例如,树木的年轮增长与温度有关。但是,它不是没有anamolies: >…从20世纪中叶树环增长低于预期的温度记录……([源](http://www.climatedata.info/Proxy/Proxy/treerings_introduction.html))如果我们只看只好,对他们我们不可能信任可靠来源,因为他们已经知道的问题。我们还可以使用珊瑚作为过去的气候指标。然而,也有些怀疑:>然而,长(multi-centure)记录很少,可能影响nonclimatic影响尚未建立自信。>[源](http://www.meteo.psu.edu/holocene/public_html/shared/articles/MannPersp2002.pdf)冰核也不能免于怀疑:>一个不争的专门的解释氧同位素的大气温度变化,moreoever,仍然难以捉摸,precie年度约会是很困难的。然而,如果我们能把这三个显示以及其他指标(花粉、地球孔等),我们可以增加我们的理解的可靠性。例如,如果大多数指标显示冷的一年,我们能更reliabiliy说那是一个寒冷。 Combining these proxies together helps us to gain a clearer picture of the past environment. **Overall Reliability** However, with that said, the amount of uncertainty with the multi-proxy method is not small. At the Workshop on Mathematics in the Geosciences, Blake McShane presented a new algorithm for estimating paleoclimate. This algorithm provided a more reliable estimate by *increasing the uncertainty* of the predictions. That's an important point that I will restate: Through his talk, he showed that his method was *more reliable* because it was *less certain*. Even that wide uncertainty level, he questioned: > Indeed, this should make us *increase* our level of uncertainty (indeed perhaps our wide intervals are in fact optimistically too narrow)! > [source](http://www.earth.northwestern.edu/people/seth/Mathgeo/mcshane.pdf) In the end, we can look at proxies for guidelines and trends, but they cannot be used for reliable readings.