When compared with the average temperatures of the years 1880–2000, average global temperatures have increased over the past couple of decades. This phenomenon is known as ‘ global warming ’.
Global Average Surface Temperature
1.0 0.8 0.6 0.4 0.2 0
–1.0 –0.8 –0.6 –0.4 –0.2
1880 1900 1920 1940 Year Question Time
1. Describe how scientists discover what temperatures were like prior to the 1900s. 2. What is climate change? 3. What evidence is there to show that global warming is occurring?
16.3 Climate Change and Human Activity
Scientists now believe that human activities have had a significant impact on global warming. Since the start of the Industrial Revolution from around 1760, human activity and industry have released large amounts of greenhouse gases ( carbon dioxide , methane , nitrous oxide ) into the atmosphere. To understand why this is harmful, we must look at the ‘ greenhouse effect ’.
The Greenhouse Effect
The greenhouse effect is the warming of the earth’s surface and the air above it. It is caused by gases in the air that trap energy from the sun. The heat-trapping gases are known as greenhouse gases.
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Industrial Revolution: A period of dramatic change in which manufacturing by hand was increasingly replaced by manufacturing by machines.
1960 1980 2000 2020
12 3 Being numerate
Looking at the period 1920– 2020 in figure 2, how many years have had temperatures above average?
Search online for ‘NASA Global temperature anomalies from 1880 to 2021’.
2. Changes in global average surface temperature, 1880–2020