Geography Text Book Pages
2
Challenges for the Planet
The causes, effects and responses to climate change
Learning objective – to study the causes and effects of climate change and how people have responded to the changes.
Learning outcomes
• To know how and why climate has changed since the last ice age. • To be able to discuss the causes of current climate change on a local and global scale.
• To know the negative effects that climate change is having on the environment and people.
• To be able to explain how people respond to climate change.
How has the world’s climate changed since the last ice age?
The graph in Figure 1 shows the trend in the world’s temperature since the end of the last ice age, approximately 10,000 years ago. The temperature since that time has increased by 6°C. Within this general trend, however, there have been a number of fluctuations. After the last ice age the temperature rose rapidly for the following 2,000 years. Between 4,000 and 8,000 years ago there were two warm periods interrupted by a colder spell. Another warm spell happened between the years AD800 and AD1200, which was known as the medieval warm period. There then followed the Little Ice Age where temperatures were below the long-term average for 600 years, ending in the late 1800s. In the past 100 years the temperature has begun to rise steadily, with greater increases since the 1960s. The temperature is projected to increase much more rapidly in the coming years, being 5°C warmer in 2100 than it is now.
7 6 Temperature change (°C) 5 4 3 2 1
Warm periods
Projected temperature change
Cooler periods Rapidly rising temperatures End of last ice age
Medieval warm period
Little Ice Age
0 8000 7000 6000 5000 4000 3000 2000 1000 Years BC
0
1000 2000 3000 Years AD
Figure 1 A graph of the world’s temperature since 8000BC
14
Unit 1 Geographical Skills and Challenges
Why has the world’s climate changed since the last ice age?
The causes of
Challenges for the Planet
The causes, effects and responses to climate change
Learning objective – to study the causes and effects of climate change and how people have responded to the changes.
Learning outcomes
• To know how and why climate has changed since the last ice age. • To be able to discuss the causes of current climate change on a local and global scale.
• To know the negative effects that climate change is having on the environment and people.
• To be able to explain how people respond to climate change.
How has the world’s climate changed since the last ice age?
The graph in Figure 1 shows the trend in the world’s temperature since the end of the last ice age, approximately 10,000 years ago. The temperature since that time has increased by 6°C. Within this general trend, however, there have been a number of fluctuations. After the last ice age the temperature rose rapidly for the following 2,000 years. Between 4,000 and 8,000 years ago there were two warm periods interrupted by a colder spell. Another warm spell happened between the years AD800 and AD1200, which was known as the medieval warm period. There then followed the Little Ice Age where temperatures were below the long-term average for 600 years, ending in the late 1800s. In the past 100 years the temperature has begun to rise steadily, with greater increases since the 1960s. The temperature is projected to increase much more rapidly in the coming years, being 5°C warmer in 2100 than it is now.
7 6 Temperature change (°C) 5 4 3 2 1
Warm periods
Projected temperature change
Cooler periods Rapidly rising temperatures End of last ice age
Medieval warm period
Little Ice Age
0 8000 7000 6000 5000 4000 3000 2000 1000 Years BC
0
1000 2000 3000 Years AD
Figure 1 A graph of the world’s temperature since 8000BC
14
Unit 1 Geographical Skills and Challenges
Why has the world’s climate changed since the last ice age?
The causes of