Prior to the mid-twentieth century thirty years of record was generally regarded as sufficient in order to define a given climate. By the 1960s the idea of a static climate was recognized as being untenable. New approaches to palaeoclimatology were developed in the 1960s to 1970s. The astronomical theory of climatic changes during the Pleistocene proposed by Croll (1867), and developed mathematically by Milankovitch, seemed to conflict with evidence for dated climate changes. However, in 1976, Hays, Imbrie and Shackleton recalculated Milankovitch's chronology using powerful new statistical techniques and showed that it correlated well with past temperature records, especially for ocean palaeotemperatures derived from isotopic (180/160) ratios in marine organisms.
Was this article helpful?
Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.