4 The end of the last ice age: the Holocene

I have already noted that the great ice sheets took about 100,000 years to form and only about 10,000 years to decay. So what happened at the end of the last ice age? Figure 15 shows the EPICA ice core CO₂ concentration and air temperature for the most recent 20 000 years, which is within the last ice age. The temperature scale shows the difference from the average temperature of the last 1000 years, so 0 °C is no
Author(s): No creator set

3.3 The Keeling curve

The Keeling curve is the plot showing the trend in rising atmospheric CO₂ concentrations since 1958 recorded at Mauna Loa in Hawaii. The story of atmospheric CO₂ in the last 50 years is a relentless rise derived from human use of hydrocarbons and, as I write this in 2008, the annual mean concentration is 383 parts per million (ppm). When Keeling first collected his CO₂ data he travelled around making the measurements at widely spaced locations – but he saw t
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3.2 The past temperature of the planet

Measuring the concentration of lead in the ice is called a direct measurement: the ice sample is melted and the water produced contains a very small but readily measured quantity of lead dust. A very accurate set of scales would be needed to measure it, but it is a directly measured quantity. There are also many indirect measurements that can be made using proxy data. The concept for using proxies is both simple and brilliant: one measured property allows inference about other states o
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3.1 Greenland's snowfall

Greenland snowfall differs depending on whether it falls in summer (when snow is comparatively warm and moist) or winter (when snow is cold and dry). These differences mean that as the snow is turned to ice, annual layers are formed that are in many ways similar to tree rings: thick annual layers mean high snowfall and thin annual layers low snowfall. The accumulation of snowfall on the summit of Greenland – and most importantly what is trapped within the crystals as it turns to ice – can
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2 The atmospheric and ocean flows

We now know that PBDEs end up in the Arctic through their physical transport by the winds, the ocean and the rivers of the world. All three mechanisms are important, but the most rapid carrier is the wind. The basic principle of global atmospheric circulation is simple: warm air rises and cold air sinks. The warming effect of the Sun is much greater at the equator than at higher latitudes and so the air is much warmer and it rises. At high latitudes the air cools and it sinks. This drives a h
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1 A climate change icon

The polar bear has become an international climate change icon. But how much is known about this bear, its habitat and life? This unit will talk about the role of language, but by way of introduction how about the name of this bear? To me it is the polar bear; to a German it is an Eisbär (ice bear) and to a French person it is an ours blanc (white bear). In these three examples the bear is referred to as polar, white, or an ice bear – eminently sensible. The Latin name fo
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Next steps
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.8 End of unit question
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.7 Summary
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.6.2 The role of modelling studies
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.6.1 Weighing up the evidence: the full cast of suspects
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.6 An evolving consensus on attribution
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.5.2 Environmental indicators
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.5.1 Physical and weather-related indicators
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.5 A ‘collective picture of a warming world’
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.4 The meaning of ‘consensus’: peer review and the IPCC process
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.3 Contested science: a case study
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.2.2 Temperature changes over the past millennium
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.2.1 Long-term rhythms in the climate
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University

2.2 Records of the Earth's temperature
Climate change is a key issue on today’s social and political agenda. This unit explores the basic science that underpins climate change and global warming.
Author(s): The Open University