Acknowledgements
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Edwards, P. N. and Schneider, S. H. (2001) Self-governance and peer review in science-for-policy: the case of the IPCC Second Assessment Report, in Miller, C. and Edwards, P. N. (eds) Changing the...
View Article2.8 End of unit question
Question 12The writer and campaigner George Monbiot wrote the following (in The Guardian Weekly, 10 February 2000): ‘Every time someone in the West switches on a kettle, he or she is helpting to flood...
View Article2.7 Summary
Reconstructions based on direct temperature measurements (back to 1860) and proxy data (Box 7) reveal that the Earth's GMST varies naturally on many different time-scales: from year-to-year, over...
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2.6.2 The role of modelling studies
State-of-the-art models are designed to simulate the workings of the climate system (in so far as this is currently understood), and include the ‘internal’ interactions that generate short-term natural...
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2.6.1 Weighing up the evidence: the full cast of suspects
Figure 36 (again adapted from the TAR) takes your thoughts on Question 11 on a stage. It gives estimates of the cumulative effect since pre-industrial times of the various climate change agents, with...
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2.6 An evolving consensus on attribution
The fact that the Earth really is warming up now commands near-universal support. However, it is one thing to detect a global warming trend that appears to be unprecedented in the past millennium...
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2.5.2 Environmental indicators
The notion of a link between climatic conditions and the behaviour of plants and animals (e.g. the growth of trees or coral) and the composition of natural communities or ecosystems (the type of...
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2.5.1 Physical and weather-related indicators
The indicators collected in Table 4 have been observed to change over large regions of the Earth during the 20th century. According to the TAR, there is now a good level of confidence that what is...
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2.5 A ‘collective picture of a warming world’
The observed increase in GMST may be the key global indicator of greenhouse warming, but it is far from being the only tangible sign of climate change during the 20th century. This brings us back to...
View Article2.4 The meaning of ‘consensus’: peer review and the IPCC process
At the time of writing (2006), debate about the ‘hockey stick’ reconstruction continues to rumble on. In this and other controversial areas, it is natural that scientists who are not part of the IPCC...
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2.3 Contested science: a case study
For complex issues such as global climate change, there are many opportunities for scientists to take issue with the findings of their colleagues. They can disagree about the procedures for gathering...
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2.2.2 Temperature changes over the past millennium
One of the most striking images in the IPCC TAR is reproduced (in adapted form) in Figure 24. Together, these two temperature records tell a compelling story, crystallised in our earlier quotes from...
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2.2.1 Long-term rhythms in the climate
The instrumental record referred to above is based on direct temperature measurements (using thermometers), and extends back only 150 years or so. Temperatures further back in time are reconstructed...
View Article2.2 Records of the Earth's temperature
To put the temperature records reported by the IPCC in context, we start with a longer-term geological perspective on the Earth's GMST.
View Article2.1 Preamble
Here are some quotes from the ‘Summary for Policymakers’ (SPM) included in the report from the scientific working group in the IPCC TAR (IPCC, 2001a):The Earth's climate system has demonstrably changed...
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1.8 End of section questions
Question 5Information on the different albedos of various types of surface was given in Section 1.2.1. Given that information:(a) Explain how a cover of snow or ice is likely to affect the amount of...
View Article1.7 Summary
Figure 12 summarises the ways in which the Earth's surface and atmosphere gain and lose energy. The main points are as follows: A proportion (the planetary albedo) of the incoming shortwave radiation...
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1.6 The human impact on the atmosphere: the coming of the industrial age
There is no doubt that CO2 is accumulating in the atmosphere. The record from Mauna Loa charts a continuing rise in CO2 concentration since measurements began in 1958, when the level was 315 ppm; the...
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1.5 ‘Radiative forcing’ as an agent of climate change
Since its first major report in 1990, the IPCC has used the concept of ‘radiative forcing’ as a simple measure of the importance of a potential climate change mechanism. The basic idea is...
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