The International Commission on Stratigraphy, however, considers the Holocene an epoch following the Pleistocene and specifically the last glacial period. Local names for the last glacial period include the Wisconsinan in North America, the Weichselian in Europe, the Devensian in Britain, the Llanquihue in Chile and the Otiran in New Zealand. The Holocene can be subdivided into five time intervals, or chronozones, based on climatic fluctuations: The Blytt–Sernander classification of climatic periods initially defined by plant remains in peat mosses, is currently being explored. Geologists working in different regions are studying sea levels, peat bogs and ice core samples by a variety of methods, with a view toward further verifying and refining the Blytt–Sernander sequence. They find a general correspondence across Eurasia and North America, though the method was once thought to be of no interest. The scheme was defined for Northern Europe, but the climate changes were claimed to occur more widely. The periods of the scheme include a few of the final pre-Holocene oscillations of the last glacial period and then classify climates of more recent prehistory. Paleontologists have not defined any faunal stages for the Holocene. If subdivision is necessary, periods of human technological development, such as the Mesolithic, Neolithic, and Bronze Age, are usually used. However, the time periods referenced by these terms vary with the emergence of those technologies in different parts of the world. Climatically, the Holocene may be divided evenly into the Hypsithermal, with warmer temperatures on average in many regions, and Neoglacial periods. The boundary coincides with the start of the Bronze Age in Europe. According to some scholars, a third division, the Anthropocene, has now begun. This term is used to denote the present time interval in which many geologically significant conditions and processes have been profoundly altered by human activities. The ‘Anthropocene’ (a term coined by Paul Crutzen and Eugene Stoermer in 2000) is not a formally defined geological unit. The Subcommission on Quaternary Stratigraphy of the International Commission on Stratigraphy has a working group to determine whether it should be. In May 2019, members of the working group voted in favour of recognizing the Anthropocene as formal chrono-stratigraphic unit, with stratigraphic signals around the mid-twentieth century C.E. as its base.