The Greenhouse Effect

As the sun’s energy warms up the Earth, our planet radiates some of this heat back out towards space. Certain gases in the atmosphere act like the glass in a greenhouse, allowing the sun’s energy in but preventing heat from escaping. Some greenhouse gases, such as water vapour – the most abundant greenhouse gas – are naturally present in the atmosphere; without them, the Earth’s average temperature would be an unbearably cold -18ºC instead of the 15ºC it is today. However, human activities are releasing immense additional amounts of greenhouse gases into the atmosphere and this is enhancing the greenhouse effect.

Feeling the heat

The consensus among the world’s leading climate scientists is that there is no doubt the climate system is warming, and that it is extremely likely that emissions of greenhouse gases from human activities are the dominant cause. The global average temperature has risen 0.85º C since the late 19th century and each of the past three decades has been warmer than any preceding decade since records began in 1850. Since the middle of the 20th century concentrations of greenhouse gases have increased, the atmosphere and ocean have warmed, the amounts of snow and ice have diminished and sea level has risen.

Need to keep warming below 2°C

The latest scientific evidence suggests that, if little or no action is taken to reduce global greenhouse gas emissions, by the end of this century global warming is likely to exceed 2°C above the average temperature in 1850-1900 and could be as much as 5°C. An increase of 2°C compared to the temperature in pre-industrial times is seen by scientists as the threshold beyond which there is a much higher risk that dangerous and possibly catastrophic changes in the global environment will occur. For this reason the international community has recognised the need to keep warming below 2°C.

CO₂ emissions rising

The greenhouse gas most commonly produced by human activities is carbon dioxide (CO₂). It is responsible for some 63% of man-made global warming. One of the main sources of CO₂ in the atmosphere is the combustion of fossil fuels – coal, oil and gas. Over the past two and a half centuries, our societies have burnt increasing amounts of fossil fuels to power machines, generate electricity, heat buildings and transport people and goods. Since the Industrial Revolution in 1750 the concentration of CO₂ in the atmosphere has increased by around 40%, and it continues to rise.

The EU is taking action to reduce human greenhouse gases emissions

Preventing dangerous climate change is a strategic priority for the European Union. Europe is working hard to cut its greenhouse gas emissions substantially while encouraging other nations and regions to do likewise. In parallel, the European Commission and some Member States have developed adaptation strategies to help strengthen Europe’s resilience to the inevitable impacts of climate change.

EU initiatives to reduce greenhouse gas emissions include:

• The European Climate Change Programme (ECCP), which has led to the implementation of dozens of new policies and measures;
• The EU Emissions Trading System, which has become the EU’s key tool for reducing greenhouse gas emissions from industry most cost-effectively;
• Adopting legislation to raise the share of energy consumption produced byrenewable energy sources, such as wind, solar and biomass, to 20% by 2020;
• Setting a target to increase Europe’s energy efficiency by 20% by 2020 by improving the energy efficiency of buildings and of a wide array of equipment and household appliances;
• Binding targets to reduce CO2 emissions from new cars and vans;
• Supporting the development of carbon capture and storage (CCS) technologies to trap and store CO2 emitted by power stations and other major industrial installations

For more information:

• European Commission – DG CLIMA website