CG5. Climate change and the greenhouse gases extension sheet. Vicky Wong. Page 1 of 2
Climate change and greenhouse gases extension sheet
For each of the questions below, ensure that you explain your answer fully.
You have looked at data about the temperature of the Earth measured by satellite and by
thermometer and at data about the change in concentration of greenhouse gases. The furthest
back the data goes is to the mid-1600s which is about 350 years. This is a very long
experiment, but when the age of the Earth is considered it is a very short length of time.
Question 1
Looking at the data you have seen so far, does the evidence support a firm conclusion
that the earth is experiencing unusual climate change?
To help support the conclusions we need to know about the temperature of the Earth further
back in time. There are no direct measurement experiments that we can look at so a new way
of determining the temperature at a given time needs to be found.
Question 2
Can you think of anything which scientists could use to help them to discover what the
temperature was hundreds, thousands and even millions of years ago?
Recently, leading scientists have also tried to answer this question. Their search for a longer
temperature record has taken them to some of the most isolated and remote places on Earth
such as the depths of the middle of the Atlantic and Pacific Oceans and the ice and snow of
Greenland and Antarctica. The scientists are applying an idea that the ‘father of geology’,
James Hutton, had in the 1700s.
In the 1700s James Hutton from Edinburgh realised that the key to understanding the future of
the planet was by investigating the past. James Hutton was the first man to study the rocks and
realise that the Earth was millions of years old. He introduced the idea of geological time, and
used fossils to learn about previous ages. Hutton’s ideas were very controversial at the time
because in 1650 Archbishop James Ussher of Ireland completed his dating of the Earth using
biblical evidence.
Ussher declared that the world was created on the evening of October 22, 4004 BC, and was
less than 6000 years old. Some people still believe this idea but it has no scientific validity.
This should not be mistaken as evidence for or against the existence of a Creator of the
Universe.
Correlation and Causation
There is a difference between correlation and causation. Different variables may follow the
same pattern (correlation) but this does not necessarily mean that one variable causes the other
to happen.
For example
 In summer we tend to wear less clothing than in winter
 In summer we tend to eat more ice cream than in winter
CG5. Climate change and the greenhouse gases extension sheet. Vicky Wong. Page 2 of 2
There is a correlation between wearing less clothing and eating ice cream, but this is not a
causation. Wearing less clothing does not make you eat ice cream.
There are 3 variables in the above: the season; the amount of clothing; what you eat.
 Changes in the season cause changes in the amount of clothing you wear
 Changes in the season cause changes in what you choose to eat
Scientists can often find correlations but it is much harder to show a causation; a mechanism
must be put forward to explain how one variable causes changes in the other.
For example
 Smokers are more likely to suffer from lung cancer than those who do not smoke
There is a correlation between smoking and lung cancer. Cigarette smoke contains over 300
toxic compounds including several carcinogens (cancer causing compounds.) It is now widely
accepted that there is a causation because of the presence of the carcinogens.
Question 3
What is the correlation between temperature and rate of reaction? What is the
causation? Using the examples above, give an example of another correlation that you
have come across in your studies of science and another example of causation.
Question 4
From the data looked at so far, is there enough evidence to support a firm conclusion
that climate change is caused by human activity? If so, what mechanism could be used
to explain it?
If not, what further evidence might be needed?