How is the climate changing?
 Martin Fowlie
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The Earth's climate has changed repeatedly in the past and there is evidence to show how life on our planet has responded to these changes. However, three things make the current situation different: the changes we are experiencing now are largely attributable to human activity; their scale is greater than has been experienced for hundreds of thousands of years; and they are happening at an unprecedented rate.
Human activities, especially the burning of fossil fuels, are releasing greenhouse gases such as carbon dioxide. This is causing the atmosphere to heat up. Greenhouse gas emissions have already caused the Earth’s surface to warm, on average, by 0.76 ºC above pre-industrial levels. The 1990s were the warmest decade on record since regular observations began in the mid-19th century.
We can avoid some of the worst effects of climate change if we limit the global average temperature rise to less that 2°C above pre-industrial levels
Predictions are that average global surface temperatures will be between 1.4-5.8 ºC above 1990 levels by 2100, and will continue to rise after that even if emissions stabilise.
We cannot now prevent the earth from warming by more than 1°C, whatever action we take. However, top climate scientists agree: we can avoid some of the worst effects of climate change if we limit the global average temperature rise to less that 2°C above pre-industrial levels. This will mean developed countries cutting emissions by 60 to 80% by the middle of this century. This can be done if, collectively, we embrace clean technologies and truly green ways of living.
This is the view not only of many scientists but also of many countries. It is the official position of the European Union (EU), agreed not only in the Environment Council but also by heads of government (Council Decision of December 2004). Importantly it is recognised that some areas have already experienced ‘too much’ temperature change, such as the Arctic and marine environments.