Climate change is one of the topics looked at in GCSE Geography. This is one of four quizzes on that subject and it looks at how we know that the Earth's climate has changed over the past 2 million years.
If you haven’t heard of climate change then you haven’t been listening in class, or to the news, or reading things on the internet, or reading things in general! I’m sure you’ll agree that there is a lot of information out there about climate change.
Depending on where your information comes from, you either hear that climate change is going to be catastrophic for the planet or that it’s a media conspiracy intended to cause a panic. However, science can use hard facts to examine the evidence of climate change. We can look at how things have changed over millions of years in the past to see if we can predict how the climate might be changing in the near future, and how that will impact us and our settlements and industry.
[readmore]Before we can look at climate change we have to decide what actually is climate? The dictionary defines climate as 'the long term pattern of weather in a particular area'. We can examine things from millions of years ago but most syllabuses only expect you to know some of the changes over the past 2 million years. A geological time span known as the Quaternary Period.
During the Quaternary Period the climate has varied between times of glaciation, also known as ice ages, and interglaciations. The last ice age is generally considered to have ended between 12,000 and 10,000 years ago. Since then we have been going through one of the Earth’s warmest periods. The difficulty for scientists is to separate natural climate change, including global warming, from man-made impacts.
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You can find more about this topic by visiting BBC Bitesize - Climate change
Climate change has been on-going for millions of years as the planet has cycled through glaciations, better known as ice-ages. However, man-made causes such as burning fossil fuels are accelerating the process
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Fossils and trace fossils can be used to reconstruct the environments, but it is a tough scientific discipline. Rocks and continents have moved over millions of years and often the plants and animals are now extinct or have evolved into a different form
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One of the main areas that scientists use the ice cores for is examining the composition of the atmosphere. Using data obtained over the past 50 or 60 years they have compared air trapped in the ice thousands of years ago to the Earth's atmosphere today
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The Industrial Revolution changed the way we operated. A massive increase in fossil fuel usage meant that carbon, previously trapped as coal and oil, was released into the atmosphere
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The data shows that as carbon dioxide levels rise the temperature also rises. Scientists can see that the carbon dioxide levels rise before the temperature rises, indicating a cause and effect
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Paleo means older or ancient, normally over geological timespans
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Whilst it is difficult to measure overall, the temperatures averaged around 14 degrees C. The trend now is that temperatures are rising
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Glaciers may be retreating as the lack of snowfall is reducing the amount of ice in general. However, this is likely to only be a small part of the reason - warmer temperatures and milder winters are more than likely the main cause
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Pollen is tiny and released in massive quantities, meaning that it is often present in cores and samples. Being unique to the species of plant, these tiny grains can tell researchers what plants were growing in the area and so allow them to reconstruct the climate
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Thousands of studies have been published on the topic of global climate change. The vast majority of them agree that there are significant man-made causes. When you read about scientists on-line that argue that this is solely a natural process, you are looking at a very small percentage. Remember, a small percentage of the world's population seriously believe the Earth is flat - there will always be people that disagree with scientifically accepted theories
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