Replacement aircraft for grounded Air NZ Dreamliners weren't as environmentally friendly. Photo / Supplied
Air New Zealand pumped 5 per cent more polluting gases into the atmosphere over the past year as green alternatives to traditional fuel remain years away and a the no-fly movement grows.
The company - this year named the ATW Eco Airline of the Year - is one of the country's biggest emitters of carbon dioxide, with its aircraft producing 3.47 million tonnes of the gas in the 12 months to the end of June.
It says the 4 per cent growth in its network and being forced lease less efficient planes to fill in for grounded Dreamliners were responsible for the increase.
READ MORE: Slow journey to alternative
Up to four of the airline's fuel efficient Dreamliner aircraft were grounded during the past year due to problems with Rolls-Royce engines.
The airline leased three Boeing 777s and depending on flight route and duration, the leased aircraft typically used 20 to 26 percent more fuel than the aircraft they replaced.
Pace developing alternative aviation fuels is slow.
''Until aviation biofuels are readily available in New Zealand or there are significant technology breakthroughs such as electric aircraft, we are unlikely to deliver further significant carbon emissions reductions through our own operations,'' Air New Zealand says in its Sustainability Report.
Climate change is ''without doubt'' the biggest risk the airline industry has faced, the report says.
The airline was already seeing the impact of climate change in New Zealand, with increasingly volatile weather patterns and severe events such as cyclones and storms affecting flights and preventing customers from getting to where they need to go.
''These weather events are no longer rare occurrences — they are happening more regularly and have become a fact of life for our operational teams which are constantly having to juggle schedules, customers and aircraft as a result.''
The aviation industry contributes between two and four percent of global emissions and global alarm at the impact of aviation on greenhouse gas emissions is growing. This had led to an expanding no fly movement symbolised by Swedish teen climate activist Greta Thunberg who sailed to a United Nations Climate Action Summit in New York.
One of the airline's sustainability advisory panel members, Tim Jackson, said in the report that the ''flygskam'' or flying shame movement was the ''last thing'' New Zealanders may want to hear about.
In Sweden where it originated there had been an 8 per cent fall in domestic plane journeys.
The professor of sustainable development at the University of Surrey said that a return flight from Auckland to London accounts for about four tonnes of carbon dioxide, 10 times the annual carbon footprint of an average Bangladeshi.
''Flying must either find a way to go fossil-free or else there must be fewer air miles factored in to a business plan rather more and more each year. Waiting for it to blow over is not really an option.''
The airline;s carbon reduction programme was vital, he says.
Air New Zealand head of sustainability Lisa Daniell responding to the climate crisis remained the airline's single biggest sustainability challenge.
During the past year there had been some progress. The number of travellers offsetting their emissions by paying into carbon schemes had grown.
During the past year 184,000 journeys were offset — accounting for 45,000 tonnes of emissions. The number of passenger journeys was up from 130,000 the previous year although this is a tiny fraction of the 17 million flights customers took.
Just on 4.6 per cent of New Zealanders offset their flights compared to 7.3 per cent of North American passengers and nearly 10 per cent of those from Britain.
Daniell said other initiatives including using ground based power while aircraft were parked and using electric vehicles had prevented more than 15,000 tonnes of CO2 from entering the atmosphere.
New schemes had reduced plastic by nearly 55 million items across the airline's network.
Although outside the period covered by the report, the airline has also stopped offering newspapers in its lounges for what it says are sustainability reasons.
Air New Zealand was awarded the Air Transport World eco airline title for its ''industry leading sustainability endeavours.''
Airlines around the world are stepping up the response to climate concerns.
The International Civil Aviation Organization, (ICAO) meeting in Montreal expressed its ''enthusiasm and support'' for the youth Climate Strike march last Friday.
''In the face of the scientific consensus on climate change, it's important to recognize that everyone has the right and responsibility to reduce their personal carbon footprint,'' the association says.
The aviation industry has already cut carbon emissions from each passenger by half since 1990, because of more fuel-efficient aircraft, and has a plan to cut net emissions by 2050 and achieve carbon-neutral growth from 2020.
Although aircraft were much more efficient today ''more action and faster innovation'' were now required to address aviation's near- and long-term impacts.
ICAO figures reflect the slow speed of developing alternatives to fossil fuel-based aviation gas.
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Since 2011 there have been 200,000 bio-fuel powered flights - around the same number as in just one day in the peak of the northern summer last year.
Michael Gill, executive director of the cross-industry Air Transport Action Group says that while electric propulsion and even hydrogen are starting to become more robust technology options for mid-and long-haul flying, a move away from fossil-based fuels and towards sustainable sources of liquid fuel was needed.
Biofuel is in regular use at five global airports, but the percentage of total fuel use is still very small.
"A transition like this cannot happen overnight. There are 11 sustainable aviation fuel production facilities currently in operation, under construction or in the final stages of financing.''
Air New Zealand says in its report that while there had been testing (including a jatropha trial in 2009) in Australasia large scale and practical volumes of biofuel remain some way off ''particularly in the absence of clear policy incentives to encourage production.''
''We know a future biofuel solution is necessary. The big challenge is being able to sustainability produce a viable aviation biofuel option at the scale required to meet aviation supply needs.''
The airline had joined with Z Energy, Refining NZ, SCION and Auckland International Airport to investigate setting up an aviation biofuel plant.
''The capital investment would be significant and it has not been achieved anywhere in the world without substantial government support to establish production and thereafter ensure fuel pricing remains viable.''
The airline is enthusiastic about hybrid electric aircraft for possible use on regional routes and has partnered with Silicon Valley firms that are developing autonomous air taxis.
New seats, bigger screens and legroom plus a luxury business premier option.