Evidence of Climate Change | AQA GCSE Geography | Climate Change 2
This revision video looks at the evidence that shows that our climate has changed significantly, including recent evidence, such as glaciers melting, sea level rise and the timings of seasonal activities, as well as historical evidence gathered by drilling ice cores and studying sediment deposits.
It is part of the AQA GCSE Geography course – Paper 1: Unit A – The Challenge of Natural Hazards.
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00:15 Recent evidence for climate change
01:53 Historical evidence for climate change
This video is about the evidence for climate change. It covers the recent evidence of climate change such as the shrinking of glaciers and ice melting, the thinning of Arctic sea ice, the rising of global sea levels, the earlier timing of seasonal activities, and the use of natural recorders such as tree rings, fossil pollen, ice cores and ocean sediments. It also explains ice cores and how they are used to estimate past climate temperatures. Finally, it explains the use of ocean sediment to observe climate change.
KEY TERMS IN THIS VIDEO
Climate change refers to the long-term change in the Earth’s climate, including average temperatures and weather patterns. It is primarily caused by the burning of fossil fuels and other human activities that release greenhouse gases into the atmosphere, which trap heat and cause the Earth’s temperature to rise.
Thinning of arctic sea ice refers to the reduction in the thickness and extent of sea ice in the Arctic region. This is largely due to warming temperatures caused by climate change, which causes the sea ice to melt.
Rising of global sea levels refers to the increase in the average level of the world’s oceans. This is largely due to the melting of glaciers and ice sheets, as well as the thermal expansion of seawater, both of which are caused by warming temperatures.
Tree rings are the concentric rings that can be seen when the cross-section of a tree trunk is examined. These rings can be used to determine the age of a tree and to reconstruct past climate conditions, as the width and characteristics of the rings are influenced by environmental factors such as temperature and precipitation.
Fossil pollen refers to the fossilized pollen grains that are found in sedimentary rock layers. These pollen grains can be used to reconstruct past vegetation and climate conditions, as different types of pollen are produced by different plants, and the abundance of different types of pollen in a particular location can be indicative of the local climate and vegetation at the time the pollen was produced.
Ice cores are long cylindrical samples of ice that are extracted from the polar ice caps or from glaciers. They can be used to reconstruct past climate conditions, as the ice contains bubbles of air that were trapped at the time the ice was formed, and the composition of the trapped air can provide information about the atmospheric conditions at the time.
Ocean sediments are layers of sediment that accumulate on the bottom of the ocean over time. These sediments can be used to reconstruct past ocean conditions, as the composition and characteristics of the sediment can provide information about the local environment and climate at the time the sediment was deposited.