It is a globally accepted fact that human activity is causing the world temperatures to rise and that buildings are responsible for nearly half of all greenhouse gas emissions. Lighting and air conditioning in buildings is mostly powered by electricity or fossil fuels (natural gas, oil and coal) which are, in both direct and indirect ways, the largest sources of CO2 emissions.
CO2 is the main greenhouse gas and its emissions have been rising ever since the first Industrial Revolution and hasn’t stopped even in the face of international treaties such as the Earth Summit in Rio de Janeiro or the Kyoto Protocol.
There are three reasons to explain this:
- The increase in world population (currently over 7 billion people and expected to reach 10billion by 2050);
- New construction is still prevalent over rehabilitation which registers at 2% of all construction works;
- Increasing consumption levels in developed and developing countries of electric appliances, air conditioning and travel;
If half of the global warming effect is the consequence of using fossil fuels in buildings, the other half can be attributed to transportation of people and commodities between them.
Urban areas are responsible for 75 to 80% of all man-made CO2 emissions and constitute the main cause of global warming. Current debates focus on presenting numbers for global warming: 1.5º to 4º temperature rise in 100 years. If you consider the average lifespan of buildings (50 to 150 years) it stands to reason that they are designed to address current temperature and weather conditions that will hardly be the same in the future.
The expression “global warming” suggests a uniform rise in temperatures, however, climate changes translate into high regional instability. For instance, increased precipitation and strong winds make it harder for people to properly identify seasons while at the same time there are more frequent draughts that render agriculture impossible in previously fertile areas. As a consequence a number of countries become in need of external assistance to access food supplies. Global warming also contributes to the melting of the ice caps which raises sea level and submerges coastal areas and riverbeds.
For a long time energy resources were abundant and because of that most of our buildings were designed and conceived with little to no regard for energy preservation. Architects, engineers and other construction professionals used to rely on unlimited available energy for air conditioning, lighting and operating utilities.
Service buildings are often fully equipped with air conditioning and several of their facades are glazed, which contributes to the greenhouse effect in the warmer seasons and significant heat losses in the colder ones.
In many urban centres the expansion of suburbs and other residential areas based on single-family homes instead of multi-family buildings causes road networks to expand. This renders public transportation inefficient and promotes the use of individual vehicles increasing carbon emissions.
Energy is an essential factor in the search for sustainability. The consumption of fossil fuels in buildings represents nearly half of all energy expenditures. Air conditioning, lighting and ventilation in buildings relies on oil, gas or coal combustion inside the buildings or in power plants.
We should, however, refrain from placing the blame on energy consumption by itself, but rather focus on fossil fuel consumption and CO2 emissions.
If society could generate the energy it needs from renewable sources this problem wouldn’t pose itself in the same way nor be so dramatic or pressing. Other conflicts could arise but they would have to be addressed on a local basis.