Climate change

• Is global warming happening?
• Is global warming a natural feature or an anthropogenic effect?
• Is global warming threatening?
• Which actions are taken?
• Which solutions do we have?

Recorded data indicate an increase in the average temperatures of the Earth's atmosphere and oceans of about 0.6°C in the last century, particularly in the last decades. This trend, consistently observed worldwide, supports significant warming on a global scale. Nevertheless, accurate temperature curves can only be constructed for the last 150 years and predictions on further evolution and interpretations based on this set of temperatures alone are difficult.

Since a lot of geological processes, in particular climatic processes, are related to cyclic variations (e.g. Milankovitch cycles), some researchers argue that the observed temperature change is just part of a larger cycle. However, the temperature (or climate) on Earth is not only controlled by e.g. distance from the sun, but also by the atmosphere enveloping our planet. The process by which an atmosphere warms a planet is known as the greenhouse effect. The natural greenhouse effect is a result of interactions of reflection and absorption of solar radiation. While 30% of incoming solar radiation is reflected, 51% is absorbed by land and oceans, heating them. In addition, the Earth's thermal or longwave infrared radiation from the surface is then absorbed by the atmosphere. The degree of greenhouse effect depends mainly on the concentration of greenhouse gases in the atmosphere. Important greenhouse gases are water vapour (H₂O), carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O) and ozone (O₃).

The greenhouse effect is well explained in a Flash animation on the following website

Recorded data show that CO₂ emissions have increased considerably since the industrial revolution (from about 280 to 377 ppm). The majority of the researchers link these increased emissions to the temperature increase observed in the last decades. Not only CO₂, of which the increase is attributed to burning of fossil fuels and deforestation, but also other anthropogenically induced greenhouse gases, such as fluorinated gases are probably influencing climatic changes on Earth.

If the current emission trend of greenhouse gases continues, a temperature increase in Belgium of 1 to 5°C in winter and 1.5 to 7°C in summer by 2100 (compared to 2000) is predicted by the IPCC (Intergovernmental Panel on Climate Change). Another result of the modeled climate change for Belgium includes a precipitation rise of 3 to 30% in winter and a drop of up to 50% in summer and a higher probability of heat waves. Furthermore, a sea level rise of 14 to 93 cm would be expected by 2100. Related to these predictions, the risk of floods is higher and a lower groundwater level and coastal erosion will be caused.

Measures are taken to reduce greenhouse gas emissions worldwide. The major policy responses include the 1992 UN Framework Convention on Climate Change (UNFCCC or "Climate Convention") and the 1997 Kyoto Protocol. All major greenhouse gas emitting countries participate in the former, which introduces the basic principles and preliminary steps for handling climate change at a global level. Although a stabilization of atmospheric greenhouse gas concentrations below a dangerous anthropogenic level was aimed, few definite governmental commitments were established in this Climate Convention. Under the 1997 Kyoto Protocol, 39 industrialized (Annex I) countries assumed specific emission limitations that should be reached during the 2008-2012 period. Unfortunately, the United States and Australia have not acceded to this Protocol. Furthermore, developing (non-Annex I) countries, including major emitters like China and India, have no emission restrictions. In fact, the 1997 Kyoto Protocol covers only about 28% of the greenhouse gas emissions worldwide, mainly those from Europe, Canada, Russia and Japan.

Under Kyoto and the EU 'burden sharing' agreement, Belgium is committed to achieve a greenhouse gas emission reduction of 7.5%. Although N₂O, CH₄ and fluorinated gas emissions decreased, total greenhouse gas emissions (of which CO₂ is responsible for 86% in Belgium) have risen by 1.4% compared to 1990, resulting in a level of 147.7 Mt CO₂ equivalents in 2003. This increase reflects higher emissions from road transport and residential and commercial sectors.

Under the policies and measures adopted or implemented in 2004, including the National Allocation Plan, greenhouse gas emissions in Belgium are expected to increase up to 154 Mt CO₂ equivalents in 2020. Additional measures, such as transport policy, use of biofuels, reduction of F-gas and N₂O emissions, energy efficiency and use of wood and solar energy, are proposed in the Fourth National Communication on Climate Change (under the UNFCC) and could provide a reduction of about 8.4 Mt CO₂ equivalents by 2020. Nevertheless, more efforts will still be needed to meet the Kyoto objective.

On a global scale, more research is performed on renewable and clean energy. Also in Europe, this is a priority. Indeed, in order to reduce greenhouse gas emissions in the transport sector, special attention is paid to research on hydrogen fuel cell-powered vehicles, which was funded under the Fifth Framework Programme (FP5). Moreover, as part of the Sixth Framework Programme (FP6), more than 40 institutions collaborate to improve the efficiency of wind power. Furthermore, Germany is concentrating on solar energy with the production of photovoltaic cells, while Italy already uses sea-turbine produced electricity.

While steps are taken to increase and develop the use of renewable and clean energy, the option of carbon capture and geological storage should be considered and elaborated. Although this does not handle the problem at its source, it does provide a temporary solution to lower atmospheric CO₂ concentrations during the transition to renewable energy.

More information on the problem on climate change and interesting graphs can also be found in this document (11 commented slides, 2Mb).