Carbon Footprint – the amount of carbon dioxide released into the atmosphere as a result of the activities of a particular individual, organization, or community.
Today, globally companies and industries are striving to reduce their Carbon Footprints and thus achieve the status carbon neutrality.
Carbon neutrality – it refers to achieving net-zero carbon dioxide emissions. This can be done by balancing emissions of carbon dioxide with its removal or by eliminating emissions from society.
But is carbon the only major pollutant?
Globally, aviation is responsible for around 2% of global anthropogenic CO2 emissions, but its impact is projected to rise by 200%-360% by 2050, even when the maximum use of lower-carbon alternative fuels is factored in.
But CO2, though the main contributor in the global warming and climatic change, is not the only element, there are other gases and aerosols too. Currently the aviation sector is contributing roughly over 2% of global anthropogenic CO2 emissions so the contribution of the non-CO2 warming pollutants seems to be less but what about the condition in the near future when the speculation says the rise is projected to be 200%-360%?
The ICAO Carbon Emissions Calculator is limited to the calculation of the CO2 amounts released into the atmosphere by the aircraft engines during a flight. Consequently, the ICAO Emissions Calculator does not quantify the climate change impact of aircraft emissions using the Radiative Forcing Index (RFI) or other such multipliers. ICAO is working in collaboration with IPCC (International Panel on Climate Change) on this subject and will adapt a multiplier methodology in due course accordingly. [Source – ICAO]
What is Radiative Forcing ?
It is the amount or measure of the influence a particular pollutant has in altering the balance of incoming and outgoing energy of the atmosphere.
The impact on climate due to the air transport industry is more correctly measured by Radiative Forcing (RF), measured in Watt per meter square (W/m^2). It predicts changes to the global mean surface temperature: “Positive RF” leads to global average increase in temperature and “Negative RF” leads to global average decrease in temperature.
The impacts of non-CO2 aircraft emissions at high altitudes came to prominence back in 1999 following publication of a Special Report by the International Panel on Climate Change (IPCC) on aviation. This estimated the total historic impact of aviation on the climate to have been 2 to 4 times higher than for CO2 emissions alone.
Most of the impact of these non-CO2 emissions comes from the “cruise phase” of a flight when the plane is at high altitudes. Importantly, though, this impact depends largely on atmospheric conditions, such as temperature and the background concentrations of water vapour and nitrogen oxides. All this also leads to the formation of Cirrus Clouds (thin and wispy high level clouds) on which the research has shown that these clouds are capable of trapping thermal radiation and not allowing the radiation to escape from earth atmosphere.
Nevertheless, work is ongoing to scope out ways in which non-CO2 impacts can be reduced. One good news is that the short atmospheric “lifetime” of many of these pollutants make their climatic impact highly dependent on the location, season and time of day of emissions. So, efforts can be made in the directions such as technological improvements, lightweighting, changes to (or replacements for) Bio-fuel, operational changes, and regulatory or economic options.
One of the study says Climate-friendly routing of aircraft has an exciting potential to decrease the climate impact of aviation, without the need for costly redesign of aircraft, their engines, and airports.
So, the global target should be Climate Neutrality instead of carbon neutrality, in long run, as we need to conserve our environment with the target of development which is sustainable.