Geography Sample

Geography


Geography Questions: Use of Pollen

Pollen analysis is used to assess variability in climate change over the years. This is because it has inherent qualities of rarely rotting. Also, concentrations from different species can be assessed to give an idea of the environmental changes that would have occured. In the graphs, there is evidence of pollen concentration declining over the years for all the species; along with a cumulative reduction. This was seen across all the catchment vegetations or climatic conditions. For example, for Cypernaceae, Rumex and Artemisia, the concentration in the Woodland (open grassland) was at 50%, 40% and 30% respectively between around 428 and 455 ka. This showed a decline in vegetation over time which resulted in climate changes. This could also be interpreted to represent periods during which the early Halocene was unstable. Vegetation that yields pollen thrives in matching conditions but declined when the conditions were unstable or variant. Read More


Climate Change

On studying the Northern Hemisphere temperature reconstruction provided it is clear that during the past millennium there have been many peaks and troughs in temperature variation. Looking at the linear trend line; temperatures on the whole decrease slightly and constantly from 1000 to 1900, however they then increase rapidly between 1900 and 2000. A few key peaks and troughs are shown through the 40 year smoothed reconstruction line, for example; the peak at 1170 coincides with the medieval warm period when volcanic activity was at a minimum, the trough at approximately 1453 coincides with two caldera volcanic eruptions in 1450 and 1452 which in turn scatter radiation which aids cloud formation and therefore leads to natural cooling, the wide trough from 1650-1710 coincides with a sunspot minima as well as the little ice age (LIA), before a peak in temperatures at 1750 which could link in with the industrial revolution and the production of greenhouse gasses, temperatures decrease between 1800 and 1900 which could be due to high amounts of volcanic activity; in particular the trough at 1816 which was known as the year without a summer after the eruption of Tambora in Indonesia in 1815, temperatures then increase rapidly due to the increase in greenhouse gases being used after the world wars. Read More