Carbon Impact

Aviation Carbon Impact 2021


The aviation industry has grown exponentially since in the last 20 years. With that level of growth
inevitably there is an environmental impact but thankfully, due to advancing technology, the CO2
emissions have not grown at the same rate. Whilst overall this is good news for economic growth, travel and technology development there is still a significant impact to our environment.

According to [1] aviation accounts for 2.5% of the global CO2 emissions yearly. 2.5% may sound small but the small percentage of a growing level of emissions between 2020 and forecast 2035 could be as much as 32B tonnes of CO2 emissions.

Without positive action we will continue to adversely impact the environment. Designers work on
greener technology in their propulsion and fuel systems, operators focus on efficiency, emission per passenger and waste reduction and airport operators relentlessly pursue the reduction of the
negative impacts of airport and its facilities particularly with regards to air quality, noise and light
pollution. But we all can do more.

Growth of Aviation

According to CAA data in 1990, which was considered to the boom of budget travel, the
number of passengers flying from UK airports was just over 100M in the year. By 2019 that
has nearly tripled to just under 300M per year in the UK alone.

ICAO [2] forecasts an increase of 4.5% year on year growth in revenue and therefor
passenger numbers and flights per day to 20,000 billion revenue tonne kilometers (RTK) by
2042 from 2500 RTK in 1995.

Similarly, [3] forecasts the growth of Aircraft in operation globally from 2019
to 2035 are estimated as 25,900 to 48,400 an 86% increase.

Aircraft in Operation 2019-2035
Aircraft in Operation 2019-2035

However the CO2 emissions, whilst not linear with the operational growth, has grown
7000% in the last 80 years with 3500% of that in that last 10 years and generally remains
stable at a global contribution of between 2-2.5% of all CO2 emissions.

Global aviation (including domestic and international; passenger and freight) accounts for:

  • 1.9% of greenhouse gas emissions (which includes all greenhouse gases, not only CO2)
  • 2.5% of CO2 emissions
  • 3.5% of ‘effective radiative forcing’ – a closer measure of its impact on warming.
CO2 Tonnes

When we look at the forecasted growth of aviation from 2019 to 2035 of 86%, taking no
action, this equates to 1.2B tonnes increase of CO2 by 2035 using the relatively stable
contribution of 2-2.5%.

CO2 Tonnes

Global Impact

Science daily [4] advises that for every tonne of CO2 emitted it equates directly to an
increase in 0.0000000000015 degrees of global temperature change. Using the figures
above and applying a linear increase between 2020 and 2035 aviation will have contributed
32 B Tonnes of CO2 to the atmosphere and a temperature increased of 0.048 degrees.

Extrapolate this further over another 10 years and between 2020 and 2045 aviation will be
accountable for 0.09 degree increase globally.

Degree Increase cumilative
Degree Increase cumilative

This minute change which may seem insignificant has as huge impact to our environment.

UNFCCC [5] states in it’s “race to zero” campaign that it aims to limit warming to 1.5 degrees
and achieve net zero by the mid 2040’s. With aviation continuing to grow, despite the
pandemic, it will be a significant contributory factor in either achieving or exceeding the 1.5
degree limit.

Nasa’s [6] Global climate change report finds that “limiting warming to 1.5 degrees Celsius is
expected to significantly reduce the probability of drought and risks related to water
availability in some regions, particularly in the Mediterranean (including Southern Europe,
Northern Africa and the Near-East), and in Southern Africa, South America and Australia.
About 61 million more people in Earth’s urban areas would be exposed to severe drought in
a 2-degree Celsius warmer world than at 1.5 degrees warming.”

Regardless, more of Earth’s land areas will also be affected by flooding and increased
runoff. Heavy rainfall from tropical cyclones is projected to be higher.

More areas will see increases in the frequency, intensity and/or amount of heavy

At 1.5 degrees the impact to biodiversity and wildlife is startling. Of 105,000 species studied
6,300 species of insect, 8400 species of plants and 4200 species of vertebrates will see their
climate impacted geographical range reduced by half.

Entire ecosystems will transform and shift from one type of biome to another. It is predicted
that desert and arid vegetation will expand significantly and forests will degrade.

Sustainable Aviation

Aviation by nature strives to innovate and areas of technology development to support
environmental sustainability is no different. Airbus has released it’s net zero concept aircraft
[7] using hybrid hydrogen turbofan engines. But as the description states this is still at this
time just a concept and with an estimated time into service of 2035 aviation will likely have
contributed 32B tonnes of CO2 and an increase of global temperature of 0.048 degrees.
Drone use is on the increase which have significantly less environmental impact but their
use in terms of freight and passenger movements are understandably limited at present.

In addition, this is focused on the aircraft whereas we need to look at Aviation as a total
polluter including all surrounding infrastructure and support services. Whilst Airlines are
accountable to their customers and passengers and strive to achieve on board impact
including reduction in plastic usage and net-zero flights we cannot say for certain the same
is being achieved for the large supporting network required to run an airline particularly in
airport infrastructure and maintenance support services. Many airports have banned the
use of petrol and diesel vehicles which is a significant step forward but with the overall
growth of aviation forecast globally this is not enough to offset damage already being done.

Aviation collectively must take action to understand their total impact to the environment
through their supply chains, understand what can be done to reduce it and where a solution
does not yet exist to reduce the impact work to offset the impact

This is not an action for tomorrow this is an action for now


  1. Climate change and flying: what share of global CO2 emissions come from aviation? – Our World in Data
  2. Future of Aviation (
  3. Size of aircraft fleets worldwide 2019-2039 | Statista
  4. Carbon Emissions Linked To Global Warming In Simple Linear Relationship — ScienceDaily
  5. What is Action for Climate Empowerment? | UNFCCC
  6. A Degree of Concern: Why Global Temperatures Matter – Climate Change: Vital Signs of the Planet (
  7. Airbus reveals new zero-emission concept aircraft – Innovation – Airbus

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