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Way too warming

The proposed Third Runway will contribute to increasing global heating emissions, right when we’re in a climate emergency and must rapidly reduce emissions across society. 
The Third Runway Major Development Plan addresses flight emissions in Part B – Airport, specifically Chapter B11: Greenhouse gas emissions.  


The 3rd Runway will increase emissions

• At this most critical stage of the climate emergency, Melbourne Airport is proposing that its flight emissions increase by 55% (9)

• Total annual warming from Third Runway flights will be around 16 million tonnes CO2-e (10) — comparable to the 18 million tonnes CO2-e total annual warming from Australia’s dirtiest power station, AGL Energy Limited’s Loy Yang (11)

• This is roughly 50 times the CO2-e acknowledged by Melbourne Airport — 0.348 million tonnes (12)

Construction emissions will be 422,094 tonnes CO2-e for the Third Runway, including 149,571 tonnes CO2-e from the concrete used (13)

Cumulative warming emissions total around 160 million tonnes CO2-e from the Third Runway out to 2046 (14)

Third Runway enabled flights will not be emissions free. Electric aircraft, for flights under 1,000 km, may be in service by 2050, but they won’t be emissions free until the electric grid is fully decarbonised (15)

Alternative aviation fuels are not emissions free and emissions free flight is not possible in the near term (15)

Offsetting flight emissions does not reduce aviation emissions (15)

We must reduce emissions

• Climate Action 100+, the world’s largest investor engagement initiative on climate change, in their updated Aviation Sector Strategy report drawing on IEA analysis, say that growth in air travel needs to be curtailed in order to keep the planet on track for no more than 1.5°C of global warming. The IEA’s 1.5°C scenario notes the necessity of keeping business travel to 2019 levels, capping long-haul flights of more than 6 hours for leisure reasons at 2019 levels, and shifting demand to high-speed rail infrastructure where possible.

• The IEA says we must stop developing new emissions sources (6), such as new runway-enabled flight numbers.

• Governments around the world agree we should avoid more than 1.5ºC of warming, now inevitable from emissions to date (1).

• Our own federal government says it is aiming for emissions cuts of 26-28% by 2030, and most Australians are calling for more significant cuts (7)

• Lord Deben, the chair of the UK Climate Change Committee, which advises government, said in January 2022: “There is not any space for airport expansion” (8)

We are in a climate emergency

 • Wishing we weren’t won’t get us to safety. Denying and ignoring the harmful consequences of our actions, like building a new runway, won’t prevent them. Just as we observe Total Fire Bans to minimise bushfire emergencies during fire season, so we must observe Total Runway Expansion Bans to minimise global heating during the climate emergency (1).

1.5ºC of warming is now likely by 2030. And 2ºC of warming is now likely before 2050 (2)

• Right now the Great Barrier Reef is in its death spiral and other tipping points to unstoppable warming are at hand (3)

• Aviation is the most emissions intensive form of transport, per kilometre and per hour.   

• Aviation is the world’s fastest growing source of climate breakdown emissions, growing by ~4% a year whilst other sectors continue to decarbonise (4), due to the record growth in flights (5)

• A Third Runway is incompatible with our Paris commitments, with Melbourne Airport investor ESG management guidelines, and with Melbourne Airport’s Take2 pledge. 




• The proposed Third Runway must be halted because the impact of increasing global heating emissions is an existential risk to society as we know it.

• An Environment Impact Assessment including of the increased global heating emissions, together with an “Avoidance Plan” for assessed impacts, must be completed. 

Delay submission of the Third Runway Major Development Plan to the federal transport minister, until the EIS has been presented for community scrutiny.










9. According to the MDP, a 3rd runway will enable an additional 136,500 flights per year by 2046, or a 55% increase on the pre-Covid 246,450 flights in 2018–19. See Third Runway Major Development Plan > Part A > Chapter A2 Need for the project > Table A2.3 @ 

10. In 2019, there were 246,450 flight movements at Melbourne Airport on its two runways (i).
In 2018-19 CO2 emissions from all flights departing Melbourne Airport were 4,650,000 t CO2 (ii). 
So if we assume all flights both departing and arriving is double the number departing, then the total CO2 emissions enabled by the two runways at Melbourne Airport in 2018-19 is twice 4,650,000, or 9,300,000 t CO2 (iii). 
In 2046 there are projected to be 136,500 Third Runway flight movements (iv).
So, if 246,450 flight movements in 2019 (v) created 9,300,000 t CO2, then, presuming the range of flight distances remains in the same proportion, we can estimate that 136,500 flight movements will create 5,149,898 t CO2 (9,300,000 divided by 246,450 times 136,500) in 2046. This assumes that CO2 per flight movement will not change, and that any fuel efficiency gains are cancelled out by increased longer flight movements.
But CO2 emissions contribute just a third of a flight’s total warming (vi)
So total warming from CO2 and non-CO2 flight emissions is three times 5,149,898 t, or 15,449,994 t CO2-e.
Upstream jet fuel or Well To Tank CO2 emissions for jet fuel are equivalent to roughly 20% of flight CO2 emissions. So 0.2 x 5,149,898 = 1,029,979 t CO2 (vii).  
If we add that we get 15,449,994 + 1,029,979 = 16,479,973 t CO2-e.
So Third Runway flights in 2046 will create 16,479,973 t CO2-e
(i) Melbourne Airport Master Plan, Part B > MP_B6.1.2 @ 
(ii) +  
(iii) This calculation is for arriving and departing flights total emissions, since the Melbourne Airport Third Runway Major Development Plan (MDP) reports arriving and departing flights LTO emissions.
(iv) Third Runway Major Development Plan > Part A > Chapter A2 Need for the project > Table A2.3 @  
(vii) The UK government reported in 2018 the ratio between total emissions and in flight emissions (whether as CO2 or GHG) as 1.2 (not including radiative forcing), as in, total is 120% of flight emissions. 

11. Scope 1 emissions in 2018-19 from AGL Energy Limited’s Loy Yang Power Station and Mine were 18,544,718 tonnes CO2-e (see ) 

12. The MDP only counts emissions during takeoff and landing. See

13. See Third Runway Major Development Plan > Part B > Chapter B11 Greenhouse gas Emissions > Table B11.15 

14. See Third Runway Major Development Plan > Part B > Chapter B11 Greenhouse gas Emissions > Table B11.17. The “No Build”/“Build” LTO CO2 emissions difference for 2026 is 19,340 t CO2-e, for 2031: 50,416 t CO2-e, and for 2046: 348,294 t CO2-e. Assuming a linear growth, that’s the same as: 15,538 t for 5 years between 2026 and 2030 (half the 31,076 difference between the 2026 and 2031 figures) = 77,690; 148,939 t for 15 years between 2031 and 2045 (half the 297,878 difference between the 2031 and 2045 figures) = 2,234,085; and 1 year of 348,294 (2046). Added that’s 77,690 + 2,234,085 + 348,294 = 2,660,069 t for LTO. 2,660,069 t x 20 (’cos LTO is roughly 5% of total) = 53,201,380 t. But 53,201,380 t x 3 (’cos CO2 is a third of total warming emissions) = 159,604,140 t. Or 160 million tonnes over the 20 years 2026 to 2046.



Breakthrough Centre for Climate Restoration