how do we measure climate change
Climate change has been taking place throughout the history of the Earth. It is only recently that mankind has begun to exert its own influence. Natural factors that have caused these changes have been due to changes in the Sun, volcanic eruptions and ocean circulation. We have been able to work out what the climate was like in the past by using a number of scientific methods.
Historical Records
Historical records of climate are useful in determining just what past climates were like. Such records include ancient inscriptions, government records, commercial records and diaries. Firstly, we can use records of weather events such as heavy snowfall or severe frosts. Secondly, we may use records of environmental events that are caused by weather, such as floods and droughts. Lastly, there are records of events that affect plants and animals, and depend on the weather, such as the flowering of trees or the migration of birds.
Ice Cores
As snow and ice builds up, it lays down a record of the conditions in the environment at the time of its formation. This information can be taken from the snow and ice and used to work out what the climate was like at that time.
Dendroclimatology
Dendroclimatology is the study of tree rings, and how they are linked to the climate. When the growth of a tree is stunted, the width of the tree ring for that year is narrower than the ones before and after. This lack of growth may be due to a climatic factor such as temperature or rainfall, and so we can tell what the weather was like in that year.
The Ice Ages
Records of past climates have been used to show what the climate was like during the last several hundred thousand years. These records have demonstrated that the global climate has changed from being fairly warm, as it is now, to being very cold. These cold periods are known as the Ice Ages, and the last one affected the Earth only 18,000 years ago. It is thought that the change in global climate between Ice Ages and warm periods is linked to the Earth's changing orbit around the Sun.
Historical Records
Historical records of climate are useful in determining just what past climates were like. Such records include ancient inscriptions, government records, commercial records and diaries. Firstly, we can use records of weather events such as heavy snowfall or severe frosts. Secondly, we may use records of environmental events that are caused by weather, such as floods and droughts. Lastly, there are records of events that affect plants and animals, and depend on the weather, such as the flowering of trees or the migration of birds.
Ice Cores
As snow and ice builds up, it lays down a record of the conditions in the environment at the time of its formation. This information can be taken from the snow and ice and used to work out what the climate was like at that time.
Dendroclimatology
Dendroclimatology is the study of tree rings, and how they are linked to the climate. When the growth of a tree is stunted, the width of the tree ring for that year is narrower than the ones before and after. This lack of growth may be due to a climatic factor such as temperature or rainfall, and so we can tell what the weather was like in that year.
The Ice Ages
Records of past climates have been used to show what the climate was like during the last several hundred thousand years. These records have demonstrated that the global climate has changed from being fairly warm, as it is now, to being very cold. These cold periods are known as the Ice Ages, and the last one affected the Earth only 18,000 years ago. It is thought that the change in global climate between Ice Ages and warm periods is linked to the Earth's changing orbit around the Sun.
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