The Earth’s climate has always been subject to change and fluctuations between prolonged warmer or cooler periods extending over several decades or even millennia.

It is today widely accepted that the accelerated global warming experienced in the past few decades is associated with the increase in greenhouse gases, and especially carbon dioxide (CO2). The mechanism underlying the greenhouse effect is generally accepted today and numerous recent studies have confirmed the growing consensus that the higher concentration of greenhouse gases is leading to climatic changes with such unwanted consequences as an increase in ocean temperatures and melting of the glaciers.

CO2 concentration is rising

Since the beginning of industrialization there has been a distinct increase in the concentration of carbon dioxide in the atmosphere. This trend is attributable, above all, to human activity. According to the latest report on global climate change published by the Intergovernmental Panel on Climate Change (IPCC), a large part of the additional carbon dioxide emissions is assumed to result from the combustion of fossil fuels in industry, transportation and space heating.

Although the emission of greenhouse gases has been reduced by just over 3 % between 1990 and 2004 in the countries which signed the UN Framework Convention on Climate Change (UNFCCC), the emission levels recorded since the turn of the millennium have tended upwards again in the majority of signatory states, according to the latest figures published by the UN Secretariat for climate change.

Forecasts by the International Energy Agency (IEA) are therefore not overly optimistic as regards meeting the targets agreed in Kyoto. The target originally set by the OECD countries was to reduce greenhouse gas emissions by 5.2 % on average from the level of 1990 by the year 2012. In its World Energy Outlook 2006, however, the IEA projects that total emissions by the OECD countries1 alone will be 29 % higher than targeted in 2010. Even if all member countries of the Kyoto Protocol were to take additional measures immediately, the present upward trend in emissions could still not be stopped by 2010. This applies particularly in light of the steadily growing emissions by those countries which have not ratified the Kyoto Protocol.

The IEA expects worldwide CO2 emissions to increase by 1.7 % annually between 2004 and 2030. According to the IEA report, total carbon dioxide emissions will exceed 40 billion metric tons by 2030 – a rise of more than 14 billion metric tons over the level in 2004.

The biggest increase is to be expected in the non-OECD countries, especially the emerging markets of Asia. They alone will account for roughly three-quarters of the global increase in carbon dioxide concentration by 2030, with China contributing 39 % of the increase. According to the IEA, China will replace the USA as the world‘s leading producer of greenhouse gases before 2010. A distinct increase in emissions is also forecast for other Asian countries, especially India, although the highly developed OECD countries will continue to produce by far the highest CO2 emissions per head of population in the future, too.

Natural greenhouse effect

As a so-called greenhouse gas, carbon dioxide (CO2) occurs naturally in the atmosphere and is vital to life on Earth. It regulates radiation processes in the atmosphere. Greenhouse gases allow short-wave sunlight (UV sunlight) to pass through and prevent the thermal radiation reflected from the surface of the Earth from escaping back into space. This heats up the Earth like a greenhouse so that it becomes inhabitable. Without the natural greenhouse effect, the average temperature of the Earth would be –18°C and not 15°C. The greenhouse effect intensifies when additional CO2 is released into the atmosphere.