Reducing air pollution helps tackle climate change

Carbon dioxide may be the largest driver of global warming and climate change but it is not the only one. Many other gaseous or particulate compounds, known as ‘climate forcers’, have an influence on the amount of solar energy (including heat) the Earth retains.

For example, methane is a very powerful climate forcer as well as an air pollutant linked to agricultural activities, closely linked to livestock production and meat consumption. Particulate matter is another pollutant, impacting both climate change and air quality. Depending upon its composition, it may have a cooling or warming effect on the local and the global climate. For example, black carbon, one of the constituents of fine particulate matter and a result of incomplete burning of fuels, absorbs solar and infrared radiation in the atmosphere and thus has a warming effect.  

Measures to cut emissions of short-lived climate forcers such as black carbon, methane, ozone or ozone precursors benefit both human health and the climate. Greenhouse gases and air pollutants share the same emission sources. Therefore there are potential benefits, including cost savings, that can be obtained by limiting emissions of one or the other.

However, in the past certain measures have been promoted to benefit, among others, climate change but which have had unintended negative impacts on air quality. For example, many countries  promoted diesel vehicles but which have turned out to emit high levels of air pollutants. Similarly, the promotion of renewable wood burning in some areas of Europe has unfortunately led to high levels of particulate matter in the local air. We must learn from such examples and make sure the consequences of the measures we choose to implement are properly understood and factored in.

The links between climate change and air quality are not limited to common pollutants released into the atmosphere from the same sources. Climate change can also aggravate air pollution problems. In many regions across the world, climate change is expected to affect local weather, including the frequency of heat waves and stagnant air episodes. More sunlight and warmer temperatures might not only prolong the periods of time in which ozone levels are elevated, it may also exacerbate peak ozone concentrations further. This is certainly not good news for parts of Europe, experiencing frequent episodes of excessive ground-level ozone.