Environment and roads

What is climate change?

It's important to understand that climate change is a natural process; our climate has always changed and will continue to do so. However, the term 'climate change' is increasingly used to refer to the identified changes in our climate since the early part of the 1900s. The changes we've seen over recent years, including those predicted over the next 80 years or so, are thought to be mainly as a result of human activities contributing to and enhancing the natural climate change process.

'Man-made' climate change is the recent warming of the Earth, and its associated impacts, that are being primarily driven by a rise in the atmospheric concentrations of greenhouse gases such as carbon dioxide and methane.

The Earth’s global average temperature is controlled by the so-called 'greenhouse effect'. Gases such as carbon dioxide in the atmosphere allow much of the energy from the Sun to pass through and warm the Earth’s surface but absorbs some of the heat that is radiated back out. Without the greenhouse effect the average temperature of the Earth’s surface would be about 33^oC lower than it actually is today.

The natural greenhouse effect is now being enhanced by increasing greenhouse gas emissions arising from human activities. This is leading to greater, more rapid, warming than would be expected naturally.

The global average temperature has risen by about 0.74^oC in the last 100 years, with much of this occurring as rapid warming (0.55^oC) since the 1970s. This may not seem much compared with daily fluctuations in temperature, but in fact the global average temperature today differs by only about 5^oC compared with the last Ice Age. Eleven of the last 12 years rank among the warmest since records began in 1850.