by Wayne persky |
RSS Feed Recent research from the University of Leeds discusses the outsized impact of long-distance travel on greenhouse gas (GHG) emissions, suggesting this is luminal a primary driver of global warming. Is it really? The article points out that despite accounting for less than 3% of all trips by UK residents, long-distance journeys (defined as trips over 50 miles one way) are responsible for a staggering 70% of all passenger travel-related carbon emissions (University of Leeds, 2024, July 2).1 The disparity is even more pronounced when looking at international travel alone, which constitutes just 0.4% of total trips but contributes 55% of emissions. This stark contrast underscores the importance of targeting long-distance travel to achieve meaningful reductions in carbon emissions.
The research suggests that current efforts to reduce carbon emissions from passenger travel have focused too narrowly on local and commuter travel, overlooking the significant impact of long-distance travel. Policymakers are encouraged to reassess their strategies and prioritize initiatives that target long-distance travel, especially flights, to achieve more substantial emission reductions.
The research suggests that current efforts to reduce carbon emissions from passenger travel have focused too narrowly on local and commuter travel, overlooking the significant impact of long-distance travel. Policymakers are encouraged to reassess their strategies and prioritize initiatives that target long-distance travel, especially flights, to achieve more substantial emission reductions.
This begs the question, "How are emissions by commercial aircraft regulated?"
The International Civil Aviation Organization (ICAO) is a specialized agency of the United Nations, and it plays a significant role in regulating aircraft emissions. In 2016, ICAO adopted the first-ever global CO2 emissions standard for aircraft, which will apply to new aircraft designs from 2020 and to new deliveries of existing designs from 2023. This standard aims to improve fuel efficiency and reduce CO2 emissions.
The ICAO also developed the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). CORSIA is a global market-based measure to offset CO2 emissions from international flights. It aims to stabilize net CO2 emissions from international aviation at 2020 levels by requiring airlines to purchase carbon offsets for emissions that exceed those levels.
The EU has incorporated aviation into its Emissions Trading System (EU ETS). Under this system, airlines operating within the European Economic Area (EEA) must monitor, report, and verify their CO2 emissions and surrender allowances corresponding to those emissions.
The Environmental Protection Agency (EPA) in the U.S. has set greenhouse gas (GHG) emission standards for aircraft, aligning with ICAO's standards. However, these regulations have faced criticism for not being stringent enough to significantly reduce emissions.
The ICAO also developed the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). CORSIA is a global market-based measure to offset CO2 emissions from international flights. It aims to stabilize net CO2 emissions from international aviation at 2020 levels by requiring airlines to purchase carbon offsets for emissions that exceed those levels.
The EU has incorporated aviation into its Emissions Trading System (EU ETS). Under this system, airlines operating within the European Economic Area (EEA) must monitor, report, and verify their CO2 emissions and surrender allowances corresponding to those emissions.
The Environmental Protection Agency (EPA) in the U.S. has set greenhouse gas (GHG) emission standards for aircraft, aligning with ICAO's standards. However, these regulations have faced criticism for not being stringent enough to significantly reduce emissions.
Technology continues to improve efficiency.
While regulatory measures are in place, the aviation industry also relies on technological advancements (such as more fuel-efficient engines and lighter materials) and operational improvements (like optimized flight paths) to reduce emissions.
Programs like CORSIA and the EU ETS aim to mitigate emissions through market mechanisms, but their effectiveness can be influenced by the cost and availability of carbon offsets and allowances.
There is ongoing research and development into sustainable aviation fuels (SAFs), which can significantly reduce lifecycle CO2 emissions compared to conventional jet fuels. Regulatory support and incentives are important for the widespread adoption of SAFs.
Programs like CORSIA and the EU ETS aim to mitigate emissions through market mechanisms, but their effectiveness can be influenced by the cost and availability of carbon offsets and allowances.
There is ongoing research and development into sustainable aviation fuels (SAFs), which can significantly reduce lifecycle CO2 emissions compared to conventional jet fuels. Regulatory support and incentives are important for the widespread adoption of SAFs.
Regulations need to be coordinated.
Effective regulation of aircraft emissions requires global coordination, as aviation is inherently international. Differing regulations and standards across regions can complicate compliance for airlines
But will tightening aircraft regulations significantly reduce GHG emissions?
Aviation accounts for approximately 2-3% of global CO2 emissions. While this may seem small, the impact is amplified due to the high-altitude release of these emissions, which has a greater warming effect than ground-level emissions.
Aircraft emissions contribute to radiative forcing, a measure of the change in energy balance in the Earth's atmosphere due to greenhouse gases (GHGs) and other pollutants. The combined effects of CO2, water vapor, nitrous oxides, and particulates from aircraft (especially in the upper atmosphere) can significantly enhance global warming. The entire transportation sector is responsible for about 14% of global emissions, with aviation being a subset of this figure.
Aircraft emissions contribute to radiative forcing, a measure of the change in energy balance in the Earth's atmosphere due to greenhouse gases (GHGs) and other pollutants. The combined effects of CO2, water vapor, nitrous oxides, and particulates from aircraft (especially in the upper atmosphere) can significantly enhance global warming. The entire transportation sector is responsible for about 14% of global emissions, with aviation being a subset of this figure.
Looking at the statistics.
- Electricity and Heat Production — 25% of global GHG emissions.
- Agriculture, Forestry, and Land Use — 24% of global GHG emissions.
- Industry — 20% of global GHG emissions.
- Transportation — 14% of global GHG emissions.
- Buildings — 6% of global GHG emissions.
The largest source of GHG emissions globally is the burning of fossil fuels.
1. As noted above, generating electricity and heat (energy production) account for about 25% of global emissions.
2. Agriculture, Forestry, and Other Land Use (AFOLU) contributes to emissions through activities such as deforestation, land use changes, and agricultural practices. It accounts for about 24% of global emissions. This sector contributes through CO2, methane (CH4), and nitrous oxide (N2O) emissions.
Roughly 75% of the emissions produced by industry are due to burning fuel in order to create heat, and the rest is associated with the production processes that transform raw materials into finished products.
4. GHG production associated with transportation is obviously associated with the burning of fossil fuels and biofuels.
5. The GHG production associated with buildings is due mostly to energy used for heating and cooling.
2. Agriculture, Forestry, and Other Land Use (AFOLU) contributes to emissions through activities such as deforestation, land use changes, and agricultural practices. It accounts for about 24% of global emissions. This sector contributes through CO2, methane (CH4), and nitrous oxide (N2O) emissions.
- About 40% of methane comes from natural sources, and the other 60% is a result of human activities. The anthropogenic (due to human activity) methane production is mostly a byproduct of agriculture, the burning of fossil fuels and biofuels, the decomposition of landfill waste, and wastewater treatment.
- Nitrous oxide is produced during various agricultural soil management processes, such as the application of synthetic and organic fertilizers, the management of livestock manure, burning of crop residues, forest fires, and certain industrial processes. Nitrous oxide amounts to about 6% of total greenhouse gas emissions.
Roughly 75% of the emissions produced by industry are due to burning fuel in order to create heat, and the rest is associated with the production processes that transform raw materials into finished products.
4. GHG production associated with transportation is obviously associated with the burning of fossil fuels and biofuels.
5. The GHG production associated with buildings is due mostly to energy used for heating and cooling.
What are the primary GHG sources?
- Approximately 76% of total GHG emissions are CO2.
- Methane is the second largest component of anthropogenic GHG production, at approximately 16%.
- Nitrous oxide amounts to about 6% of total greenhouse gas emissions.
How significant are the contributions of natural events to GHG production?
Volcanic eruptions can inject large quantities of aerosols and gases, such as sulfur dioxide (SO2), into the stratosphere, which can have both cooling and warming effects on the climate.
The primary effect of large volcanic eruptions is a temporary cooling of the Earth's surface. This is due to the reflection of solar radiation by volcanic aerosols. For example, the eruption of Mount Pinatubo in 1991 caused a temporary global temperature decrease of about 0.5°C (0.9°F) for a couple of years.
Overall, volcanic eruptions are considered to have a short-term cooling effect rather than a significant long-term warming impact. On a much smaller scale, volcanic CO2 emissions can contribute to the greenhouse effect, but this is negligible compared to human emissions.
The primary effect of large volcanic eruptions is a temporary cooling of the Earth's surface. This is due to the reflection of solar radiation by volcanic aerosols. For example, the eruption of Mount Pinatubo in 1991 caused a temporary global temperature decrease of about 0.5°C (0.9°F) for a couple of years.
Overall, volcanic eruptions are considered to have a short-term cooling effect rather than a significant long-term warming impact. On a much smaller scale, volcanic CO2 emissions can contribute to the greenhouse effect, but this is negligible compared to human emissions.
Changes in solar radiation can affect the Earth's climate.
The Sun's energy output varies slightly over time due to sunspot cycles and other solar phenomena. The 11-year solar cycle leads to small variations in solar output. While these variations can influence short-term climate patterns, they are not significant drivers of long-term global warming.
Studies suggest that changes in solar radiation have contributed less than 10% to the observed warming over the past century. But note that this is still a significant amount over which we have no control.
Studies suggest that changes in solar radiation have contributed less than 10% to the observed warming over the past century. But note that this is still a significant amount over which we have no control.
Natural processes such as decomposition and respiration can release GHGs
Natural sources of methane include wetlands, termites, and oceanic processes. While these sources contribute to the greenhouse gas inventory, their levels have been relatively stable over time. But again, these sources are beyond our control.
Natural CO2 emissions come from processes like respiration and ocean-atmosphere exchanges. However, natural CO2 emissions are balanced by natural sinks like photosynthesis and ocean absorption, so they don't significantly contribute to the observed increase in atmospheric GHG concentrations.
Natural CO2 emissions come from processes like respiration and ocean-atmosphere exchanges. However, natural CO2 emissions are balanced by natural sinks like photosynthesis and ocean absorption, so they don't significantly contribute to the observed increase in atmospheric GHG concentrations.
Do carbon offsetting schemes actually have any merit?
Carbon offsetting schemes are mechanisms designed to compensate for emissions of carbon dioxide (CO2) and other greenhouse gases (GHGs) by funding equivalent CO2-saving projects. While the concept of carbon offsetting has theoretical merit, its effectiveness and impact can vary significantly depending on how the schemes are implemented.
The actual benefits (if any), of these schemes is debatable. Personally, my own opinion of carbon offsetting schemes is that 10 years from now, we'll all be looking back at what a pathetically optimistic idea that was, and feeling ashamed, because it will be painfully obvious that it made absolutely no difference at all in total GHG emissions.
Why? Because precious few individuals are going to sell a carbon offsetting plan unless the practices in that plan are part of their normal operation, anyway. They're much less likely to sell a plan for which they'll have to go to the trouble of actually doing something different. Consequently, most of these plans will probably turn out to be worthless, because they involved carbon offsetting actions that are a part of normal operations, so they would have been done anyway.
And anyone who has been forced or coerced into buying an offsetting carbon scheme will surely resent being forced to do that, so that they certainly are not going to go out of their way to make sure that everything they do will minimize GHG emissions. These combined disincentives will probably cause the program to be self-defeating.
The actual benefits (if any), of these schemes is debatable. Personally, my own opinion of carbon offsetting schemes is that 10 years from now, we'll all be looking back at what a pathetically optimistic idea that was, and feeling ashamed, because it will be painfully obvious that it made absolutely no difference at all in total GHG emissions.
Why? Because precious few individuals are going to sell a carbon offsetting plan unless the practices in that plan are part of their normal operation, anyway. They're much less likely to sell a plan for which they'll have to go to the trouble of actually doing something different. Consequently, most of these plans will probably turn out to be worthless, because they involved carbon offsetting actions that are a part of normal operations, so they would have been done anyway.
And anyone who has been forced or coerced into buying an offsetting carbon scheme will surely resent being forced to do that, so that they certainly are not going to go out of their way to make sure that everything they do will minimize GHG emissions. These combined disincentives will probably cause the program to be self-defeating.
In conclusion,
When put into perspective, it's obvious that long-distance commercial aircraft flights contribute only a relatively small amount of GHG emissions when compared with other major sources of anthropogenic GHG emissions. However, recent research shows that, despite being a small fraction of overall trips, these journeys contribute significantly to global warming, due to the fact that these emissions occur at relatively high levels in the atmosphere, where they have a greater effect on global warming.
Overall, global warming is occurring as a result of many aspects of human existence as we all try to not only survive, but also take advantage of the available comforts and every day pleasures that modern technology has to offer. The planet could probably continue to support us for at least thousands of generations, if we didn't produce so many GHG emissions that interfere with the planet's solar energy balance.
But at the current rate, global warming will eventually make the production of adequate amounts of food increasingly difficult, and at some point, impossible. Hopefully, we can correct the problem long before we get to that point. Ultimately, it will require a blend of regulation, innovation, and international cooperation, if we ever hope to make any meaningful progress in combating global warming.
Overall, global warming is occurring as a result of many aspects of human existence as we all try to not only survive, but also take advantage of the available comforts and every day pleasures that modern technology has to offer. The planet could probably continue to support us for at least thousands of generations, if we didn't produce so many GHG emissions that interfere with the planet's solar energy balance.
But at the current rate, global warming will eventually make the production of adequate amounts of food increasingly difficult, and at some point, impossible. Hopefully, we can correct the problem long before we get to that point. Ultimately, it will require a blend of regulation, innovation, and international cooperation, if we ever hope to make any meaningful progress in combating global warming.
References
1. University of Leeds. (2024, July 2). True scale of carbon impact from long-distance travel revealed. Phys.org, Retrieved from https://phys.org/news/2024-07-true-scale-carbon-impact-distance.html?utm_source=nwletter&utm_medium=email&utm_campaign=weekly-nwletter
