The climate of our planet has always been changing; previously changes have been a result of natural causes, changes in the earth’s orbit, fluctuations in the sun's energy, volcanic eruptions, and interactions between the ocean and the atmosphere.
However, today there are indications that increased human activity is increasing the rate and magnitude of climate changes. The main human influence on global climate is likely to be the increase in emissions of greenhouse gases such as carbon dioxide and methane.
The natural Greenhouse Effect is important for the existence of life on earth; it describes the gases which surround the earth trapping some of the suns heat, keeping the temperature at around 15 degrees C. Since the industrial revolution, human activities have resulted in an increase in natural greenhouse gases. The accumulation of these gases in the atmosphere enhances the greenhouse effect.
At present, just over 7 billion tonnes of carbon dioxide is emitted globally each year through fossil fuel use, and an additional 1.6 billion tonnes through land use change, largely by deforestation. An increase in these gases in the atmosphere enhances the atmosphere's ability to trap heat, which leads to an increase in the average surface temperature of the Earth.
Climate refers to the average weather experienced over a long period. There are global changes expected as a result of climate change in temperature, wind and rainfall patterns.
- The earth has warmed by 0.74°C over the last hundred years. Around 0.4°C of this warming has occurred since the 1970s. By 2100, global average temperatures are predicted to rise by between 1.4°C and 5.8°C. (the global average temperature during the last ice age was only around 5°C lower than today).
- By the second half of the 21st century, wintertime precipitation in the northern mid to high latitudes and Antarctica will rise, however, Australasia, Central America and Southern Africa is likely to see decreases in winter precipitation.
- Global sea levels are likely to rise between 200mm and 600mm by the end of this century, as a result of continued melting of ice caps, glaciers and sea ice, changes in rainfall patterns and intensification of tropical cyclones. It is thought the West Antarctic ice sheet is unlikely to collapse this century. If it does fall apart, sea level rises would be enormous.
- More hot days over land areas and fewer cold days and frost.
- More intense precipitation events.
To find out more about the effects climate change will have on Shropshire in the future and some of the projects Shropshire is working on please follow the links on this page.