Global climate change; A geological perspective. Geoscience in south-west England

• Main Authors: M B Hart, A B Hart Hart, M B, Hart, A B, A B Hart
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2000
• Subjects: Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1075.4694; http://www.ussher.org.uk/journal/00s/2000/documents/Hart_Hart_2000.pdf

Climate is changing globally! The world is about 0.6°C warmer than 100 years ago and, in the UK, seven of the warmest years ever recorded have been in the present decade. The 1990's have, so far, been about 0.5°C warmer than the average and the five warmest years in the 340-year Central England Temperature Series have occurred since 1988. Coupled with these temperature changes there is evidence of major change in the world's atmosphere. The levels of ozone in the atmosphere, particularly over Antarctica, are known to be decreasing. Concentrations of atmospheric carbon dioxide are known to be rising and this rise can be traced back to the industrial revolution; it is reportedly anthropogenic and not (apparently) part of a natural cycle. The debates over the cause of these changes, and their impact, will continue well into the future. While many find it difficult to come to terms with the idea of climate change, geologists have a wealth of experience to bring to the discussions. Ten thousand years ago the last ice age maximum was coming to an end, with temperatures changing and sea level rising rapidly as a direct result of the melting icefields. Since that time there have been less severe, but nonetheless significant reversals of the warming trend. Historians have vividly described the effects of the "little ice age" when the River Thames regularly froze in winter over an extended period of years. Geologists appreciate these global changes and have documented the climatic changes that have shaped the planet over periods of hundreds of millions of years. Using radiometric and palaeomagnetic time-scales we now have an appreciation of the natural rates of change that have left a record in the geological succession. The current climatological data suggest a modern rate of change that is beyond our geological experience and, as a direct consequence of this, there have been established a number of key bodies; e.g., the UK Climate Impacts Programme and the Inter-Governmental Panel on Climate Change. Models of climate ...