Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgements
- List of Permissions
- 1 Defining and exploring the key questions
- 2 An introduction to models and modelling
- 3 The palaeo-record: approaches, timeframes and chronology
- 4 The Palaeo-record: archives, proxies and calibration
- 5 Glacial and interglacial worlds
- 6 The transition from the last glacial maximum to the Holocene
- 7 The Holocene
- 8 The Anthropocene – a changing atmosphere
- 9 The Anthropocene – changing land
- 10 The Anthropocene: changing aquatic environments and ecosystems
- 11 Changing biodiversity
- 12 Detection and attribution
- 13 Future global mean temperatures and sea-level
- 14 From the global to the specific
- 15 Impacts and vulnerability
- 16 Sceptics, responses and partial answers
- References
- Index
1 - Defining and exploring the key questions
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface
- Acknowledgements
- List of Permissions
- 1 Defining and exploring the key questions
- 2 An introduction to models and modelling
- 3 The palaeo-record: approaches, timeframes and chronology
- 4 The Palaeo-record: archives, proxies and calibration
- 5 Glacial and interglacial worlds
- 6 The transition from the last glacial maximum to the Holocene
- 7 The Holocene
- 8 The Anthropocene – a changing atmosphere
- 9 The Anthropocene – changing land
- 10 The Anthropocene: changing aquatic environments and ecosystems
- 11 Changing biodiversity
- 12 Detection and attribution
- 13 Future global mean temperatures and sea-level
- 14 From the global to the specific
- 15 Impacts and vulnerability
- 16 Sceptics, responses and partial answers
- References
- Index
Summary
Global changes present and past
Any of our ancestors living a full three score years and ten in Western Europe some 11 600 years ago would have experienced, during their life time, truly remarkable changes in climate. Evidence from that time shows that the main changes took place over a period of 50 years at most. Although different lines of evidence give different figures for the degree of warming, it would be difficult to argue for an increase of less than 4 °C in mean annual temperature over much of Western Europe. In many areas, the shift would have been substantially greater. Parallel changes varying in nature and amplitude, but often synchronous in timing, took place over much of the Earth. The stratigraphic signal of these changes in the records from sediments and ice cores marks the transition from glacial times to the opening of the Holocene, the interglacial in which we live. Here then, was a period of rapid ‘global change’. We may infer from this that there is nothing so very special about what we now think of as global change, that is, the current and impending changes in the Earth system driven by human activities. We would be quite wrong. The changes under way at the present day are of a different kind. At this stage, we need consider only three key differences:
The rate of change in atmospheric CO2 concentrations exceeds the mean rate during glacial–interglacial transitions by one to two orders of magnitude (Raynaud et al., 2003).
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- Information
- Environmental ChangeKey Issues and Alternative Perspectives, pp. 1 - 18Publisher: Cambridge University PressPrint publication year: 2005