Interpreting Past Climate Data
One of the ways of working out what might happen to our climate in the future is to look at what has happened in the past. In this section, you will find past data on three different time scales:
- IOW weather data from 1918 to the present;
- Temperatures from central England dating back to 1660;
- Estimated average temperatures for Britain for the past 450,000 years.
These figures illustrate the difficulty of drawing conclusions from the past. Firstly, it is clear that there is no such thing as a ‘normal’ temperature. For hundreds of thousands of years our climate has fluctuated between cold ice ages, when most of Britain was buried beneath thick sheets of ice, and warmer interglacial periods. At the moment we are in one of these warm periods. Separating the amount of warming that is caused by human activities, from the warming associated with these natural cycles; is a major challenge for those seeking to predict the future.
The conclusions drawn from the past data will depend very much on the time scale you look at. Looking at the data from 1660s to the present, it appears that there has been a significant warming in recent decades and it is tempting to put this down to human activity. Historical records show, however, that the period from 1450-1890 was particularly cold. This period is known as the Little Ice Age, with particularly cold periods in the 17th and 19th centuries. It is therefore difficult to know whether the recent warming trend represents a natural recovery from this cold period, or whether it is the result of pollution caused by humans activity.
Looking on the timescale of hundreds of thousands of years, it would appear that we are at present in a warm interglacial period which may well end at any time.
Difficulties like these have led climate scientists to rely more on the use of computer models than extrapolations from past data. See the ‘Future Climate’ section for the predictions of the most recent computer models.
General Temperature trends for Central England (1659 – 2007)Using the data provided from Island Weather, we have compiled the following graph to summarise the temperatures recorded between 1659 and 2007 in Central England.
The graph shows the recorded temperatures and compares the mean summer and winter temperatures to the annual temperature. The trend lines show that overall there was an increase in mean temperatures between 1659 and 2007, with both the mean summer and mean winter temperatures getting warmer.
Ryde Data 1918 – 1996The following graphs have been compiled using data from "70 years of Weather" by Kenneth Hosking. The trends show a general increase in sunshine hours and temperature but a slight decrase in rainfall.
UK Climate from 1914-2004Visit UK Climate Projections for other comparison graphs and maps. Using general graphs for the whole of the UK can help to show how the Isle of Wight compares to national trends.
© UK Climate Projections 2009
Global Temperatures for the last 450,000 years
This graph shows that throughout history there has been change in the annual temperatures, with some periods being warmer than average and some cooler than average. The pattern appears to go in cycles with cooler spells interrupted by warmer interglacial periods.