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7.2 Comparing modelled and observed temperature

The IPCC comparison between modelled and observed temperatures since the year 1860 is shown in the three charts below

6 Further reading

The models being used in research take such simple energy flows and increase the ‘granularity’ of the components used, to build complex time sequences.

You may like to see Modelling climate change (Information Sheet 8) at the website of the Author(s): The Open University

4 Further reading

For information on changes to flora, click on Science magazine.

For changes to fauna, and economic effects, go to Information Sheet 4, or for the paper quoted at the top of the screen, Information Sheet 1, both at Climatic Research Unit.

Click on the link below to open the data-smoothing information


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2 A 4.6 billion-year history

Climate change is a natural process of warming and cooling that has occurred all through the Earth's history. Throughout geological time there have been ‘hot-house’ periods and ice ages. In order to understand the current situation, it is necessary to have some sense of context and perspective, from historical and geological time-scales. The document below shows a chart showing a generalised temperature history of the Earth.

Click on the link below to see the chart


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5.6 Land and water pollution

In this section we will just take a couple of examples that show how easy it is to expose ourselves to long-term damage inadvertently. Pesticides, developed to control insects and other vermin, can increase agricultural productivity. Although pesticides were originally hailed as one of the wonders of modern technology, it was quite quickly discovered that there was a downside to their widespread use. One problem was that of bioaccumulation. Pesticides tended to be stable chemicals and
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5.3 Global warming

Media attention has been such that it would be hard to have missed the fact that global warming is considered to be a ‘bad thing’. Why should this be so? What is so wrong with being a bit warmer? Anyway, is global warming really occurring and, if it is, what are the causal factors responsible for it?

Let us deal with this last question first. As we sit on a beach in summer, or in a sunny window seat in winter, we are aware of the Earth being warmed by the Sun. In fact the Earth is w
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4.7 Summary

Human activity has been responsible for some extinctions and othe deleterious changes to habitats. These changes have not always been the result of thoughtless or selfish behaviour; often intentions were worthy, but outcomes were not as predicted. The importance of genetic diversith is demonstrated here in relation to Dutch Elm disease. The need to retain genetic diversity in plants, used for food and medicine, is recognized in such initiatives as the Kew Milennium Seed Bank Appeal.


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3.4 Debates about rights

There are at least four big debates about modern individual rights. The aim in putting these before you is to introduce these hotly contested issues to which there are no conclusive answers, but which help frame discussions about human rights. Considering these debates is designed to help you weigh up the different arguments and form your own opinions about the meaning and effectiveness of rights claims.

The first debate concerns how our rights are grounded. One view is that our
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Learning outcomes

After studying this course, you should be able to:

  • relate the temperature of a solid to the mean kinetic energy of its atoms

  • use models for thermally induced effects that involve linear, exponential and step changes

  • use exponentials, logarithms and graphical methods to interpret data from a thermally activated process in terms of Arrhenius's law

  • identify the changes of phase taking place in a variety of critical phenomena


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Appendix 2 Acronyms

APCangle-polished convex (connector)
ASEamplified spontaneous emission
ASKamplitude shift keying
cwcontinuous wave
DSFdispersion-shifted fibre
DWDMdense wavelength division multiplexing
EDFAerbium-doped fibr
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2.1 Light sources and detectors

The basic building blocks of an optical-fibre link are the light source, the fibre and the detector (Figure 1).

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Acknowledgements

Course image: Shever in Flickr made available under Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence.

Grateful acknowledgement is made to the following sources for permission to reproduce material in this course:

Pages 36–37: Edwa
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5.14.1 Multistage flash distillation

In this process (Figure 34) saline water (screened first, if it is sea water) is distilled under reduced pressure in a series of sealed tanks. Due to the reduced pressure, the water evaporates suddenly or 'flashes' at a temperature lower than 100°C, typically 80°C. Pure water condenses on cooling coils in the tanks and is collected. As the temperature of the feed water falls in each succeeding tank (as the latent heat of evaporation is extracted from it) a correspondingly lower pressure has
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5.14 Desalination

In many parts of the world, surface water or non-saline groundwater stocks are not adequate to satisfy the water demand. While one may immediately think of the Middle East as being one such area, it is less obvious that many islands (e.g. the Canary Isles, Madeira, the Channel Islands) also suffer the same problem. In such circumstances, people have been forced to consider the sea and brackish underground aquifers as water sources. To make these saline waters potable, the salt has first to be
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4 Introduction to systems practice

This course teaches some aspects of systems thinking and practice. But what does it mean to be a systems practitioner, and is it different to being a manager? This section attempts to answer those questions.

First, I believe a good systems practitioner will be more competent at handling complex situations, more capable of managing their working and domestic lives, and more able to learn not only how to learn but also how to act more effectively by using systemic concepts and techniques.
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1.6 Building on strengths

Activity 1

A self-review exercise for your learning file

The aim of this activity is to encourage you to take a problem-solving approach to your own learning, and to be proactive. The first part asks you to refle
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Inuit Throat Singing
In many cultures, song is perhaps one of the most important traditions. What is extraordinary about the Inuit musical tradition is the way they create their songs - with notes originating from their throats. The song isn't interrupted even when a breath has to be taken. The 6 tracks in this album focus on Tanya Tagaq, who describes the amazing art of throat singing and how her heritage and culture, carried in her heart forever, has driven her to continue with this unique tradition. This mater
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Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

Ethics in real life
Ethical standards play a key role in the conduct of individuals and societies. This audio album contains three tracks that examine the basics of ethical theory and practice. It features interviews with leading figures in the field of ethics and examines codes of ethics, corporate businesses and copyright infringement. This material is taken from The Open University course A181 Ethics in real life. Th
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1 Enlightenment, liberty and revolution

The main aim of this course is to provide you with basic historical background on the French Revolution, which marked a watershed in the history and culture of the period 1780–1830. The documents and illustrations associated with it are there to illustrate and bring out the points made. The first exercise is preceded by an extended preamble designed to facilitate your reading and understanding of the first document. This should in turn point a way towards engaging with other documents and i
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Keep on learning

Study another free course

There are more than 800 courses on OpenLearn for you to c
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