We could cut particulate pollution from air travel by 60% – but the journey has run into turbulence

Oh, lovely. Image: Getty.

When it comes to reducing carbon emissions, one of the biggest hurdles is the world’s addiction to flying. And this is only going to get more intense as developing countries grow bigger middle classes who want to explore the world for business and pleasure. The Conversation

In the UK, the climate change minister, Nick Hurd, has named transport as one of the two biggest environmental challenges facing the world. But while the government continues to invest in research and infrastructure for electric vehicles, clear action on addressing carbon dioxide for air transport has been lacking.

Our researchin collaboration with Manchester Metropolitan University and Missouri University of Science and Technology has shown that greener aviation fuels could cut not only carbon emissions but also reduce wider air pollution and improve air quality – a key issue in the ongoing debate around Heathrow’s proposed expansion.

The landmark 2015 Paris Agreement on addressing climate change did not include two sectors – aviation and maritime. This is despite aviation accounting for 2 per cent of global carbon dioxide emissions. This figure is growing by around 3 per cent a year. Attempts to decarbonise the aviation sector have so far proven complicated.

The process has been delayed by governments trying to agree on how to account for emissions: if a Dutch airline takes off in America and lands in Brazil, which country should take the responsibility for those emissions? The good news is that, in the autumn of 2016, the world’s governments came together under the UN’s specialist agency for aviation, the ICAO and finally reached an agreement. But this agreement is still voluntary and allows airlines to “offset” their carbon emissions.

Beyond this, the industry has set itself a targetto achieve carbon-neutral growth by 2020 and to halve emissions by 2050 compared to 2005 levels. This ambition can only be achieved by a combination of efforts including improvements in engine and airframes, such as new materials to make aircraft lighter, a more emissions-optimised approach to air traffic management and, crucially, by introducing greener alternatives to jet fuel.

These alternative aviation fuels could offer the UK airline industry between 15 per cent and 24 per cent reduction in CO2 emissions by 2050. The UK government is starting to take action, including issuing a consultation on whether to increase the obligation it puts on airlines to increase the level of so-called “renewable fuel” used currently. Running in parallel with this has been a consultation on the future growth of Heathrow airport – and, even in this, alternative fuels could play a part both in terms of lower CO2 emissions if alternative fuel use is increase, and because these fuels contain fewer particulates than conventional fuels.

Our research has shown that particulates from air travel could be reduced by up to 60 per cent by using synthetically produced fuels from feedstocks such as old cooking oil. In simple terms, the oil-baring feedstock can be heated with a catalyst to change its structure and extract the useful chemicals to form a type of fuel that can be used to power jet aircraft.

The Airbus 319 burns 640 gallons of fuel per hour. Image: Nordroden.

There are, of course, challenges which need to be overcome if the role of alternative aviation fuels in tackling climate change and air pollution is to be realised.

Aviation fuel has not changed substantially since the 1960s. The focus of improvements in the efficiency of engines and airframes has been on the continued improvements to technology to the point where we have a highly optimised system based on the use of traditional fuels. If the industry adopted fuels developed from non-conventional sources such as bio-crops this may, in turn, make it possible for the indsutry to make further improvements in engine and airframe technologies based on new fuels. There are three major challenges facing the industry.

Three challenges

Safety: This is the most obvious problem to overcome. The approval process for new fuels is extremely rigorous – airlines will not use fuels unless they know they are completely safe and will not affect the operation and reliability of the aircraft. This process can take several years to complete. To date, only a handful of alternative production routes have been approvedand the sector’s experience of dealing with new molecules in the jet fuel is increasing. Better modelling and earlier testing of fuels should help reduce the time, and cost, of this approvals process and efforts such as the US FAA and the ASCENT programme which aim to accelerate the approvals process in the future.

Economics: The technology for producing alternative aviation fuels is still relatively immature and at a small scale which means that the cost remains higher than for fuel from conventional sources. Further research and development – and increasing the scale of production – will address these issues, as will the introduction of regulations which reward and incentivise airlines to use these fuels.

Sustainability: We need to ensure that the production of alternative fuels works for the environment and people in the regions where these are produced. So, for example, in the case of biofuels, these shouldn’t compete for land with vital food crops. The use of municipal waste or offgases from industrial processes are two alternatives which do not compete with land use are gaining some traction as alternative fuels.

This is an issue that will only get more urgent as more people in developing economies choose to travel by air. We’ve already made a good start – since 2011, more than 2,200 commercial flights have used alternative fuels– but this has to be put in a context of more than 100,000 flights being made worldwide each day.

While the current agreement is voluntary, ICAO has managed to create one of the first global agreements to apply to a specific sector on carbon emissions. Industry and academia now need to deliver the advancements – supported, needless to say, by national governments. That will be crucial if we are to see greener skies overhead any time soon.

Simon Blakey is senior lecturer in mechanical engineering at the University of Sheffield.

This article was originally published on The Conversation. Read the original article.


Was the decline in Liverpool’s historic population really that unusual?

A view of Liverpool from Birkenhead. Image: Getty.

It is often reported that Liverpool’s population halved after the 1930s. But is this true? Or is it a myth?

Often, it’s simply assumed that it’s true. The end. Indeed, proud Londoner Lord Adonis – a leading proponent of the Liverpool-bypassing High Speed 2 railway, current chair of the National Infrastructure Commission, and generally a very influential person – stood on the stairs in Liverpool Town Hall in 2011 and said:

“The population of Liverpool has nearly halved in the last 50 years.”

This raises two questions. Firstly, did the population of the City of Liverpool really nearly halve in the 50 year period to 2011? That’s easy to check using this University of Portsmouth website – so I did just that (even though I knew he was wrong anyway). In 2011, the population of the City of Liverpool was 466,415. Fifty years earlier, in 1961, it was 737,637, which equates to a 37 per cent drop. Oops!

In fact, the City of Liverpool’s peak population was recorded in the 1931 Census as 846,302. Its lowest subsequent figure was recorded in the 2001 Census as 439,428 – which represents a 48 per cent decline from the peak population, over a 70 year period.

Compare this to the population figures for the similarly sized City of Manchester. Its peak population also recorded in the 1931 Census as 748,729, and its lowest subsequent figure was also recorded in the 2001 Census, as 392,830. This also represents a 48 per cent decline from the peak population, over the same 70 year period.

So, as can be seen here, Liverpool is not a special case at all. Which makes me wonder why it is often singled out or portrayed as exceptional in this regard, in the media and, indeed, by some badly briefed politicians. Even London has a similar story to tell, and it is told rather well in this recent article by a Londoner, for the Museum of London. (Editor’s note: It’s one of mine.)

This leads me onto the second question: where have all those people gone: London? The Moon? Mars?

Well, it turns out that the answer is bit boring and obvious actually: after World War 2, lots of people moved to the suburbs. You know: cars, commuter trains, slum clearance, the Blitz, all that stuff. In other words, Liverpool is just like many other places: after the war, this country experienced a depopulation bonanza.

So what form did this movement to the suburbs take, as far as Liverpool was concerned? Well, people moved and were moved to the suburbs of Greater Liverpool, in what are now the outer boroughs of the city region: Halton, Knowsley, St Helens, Sefton, Wirral. Others moved further, to Cheshire West & Chester, West Lancashire, Warrington, even nearby North Wales, as previously discussed here.

In common with many cities, indeed, Liverpool City Council actually built and owned large several ‘New Town’ council estates, to which they moved tens of thousands of people to from Liverpool’s inner districts: Winsford in Cheshire West (where comedian John Bishop grew up), Runcorn in Halton (where comedian John Bishop also grew up), Skelmersdale in West Lancashire, Kirkby in Knowsley. There is nothing unique or sinister here about Liverpool (apart from comedian John Bishop). This was common practice across the country – Indeed, it was central government policy – and resulted in about 160,000 people being ‘removed’ from the Liverpool local authority area.

Many other people also moved to the nearby suburbs of Greater Liverpool to private housing – another trend reflected across the country. It’s worth acknowledging, however, that cities across the world are subject to a level of ‘churn’ in population, whereby many people move out and many people move in, over time, too.

So how did those prominent images of derelict streets in the inner-city part of the City of Liverpool local authority area come about? For that, you have to blame the last Labour government’s over-zealous ‘Housing Market Renewal Initiative’ (HMRI) disaster – and the over enthusiastic participation of the then-Lib Dem controlled city council. On the promise of ‘free’ money from central government, the latter removed hundreds of people from their homes with a view to demolishing the Victorian terraces, and building new replacements. Many of these houses, in truth, were already fully modernised, owner-occupied houses within viable and longstanding communities, as can be seen here in Voelas Street, one of the famous Welsh Streets of Liverpool:

Voelas Street before HMRI implementation. Image: WelshStreets.co.uk.

The same picture after HMRI implementation Image: WelshStreets.co.uk. 

Nonetheless: the council bought the houses and ‘tinned them up’ ready for demolition. Then the coalition Conservative/Lib Dem government, elected in 2010, pulled the plug on the scheme. 

Fast forward to 2017 and many of the condemned houses have been renovated, in a process which is still ongoing. These are over-subscribed when they come to market, suggesting that the idea was never appropriate for Liverpool on that scale. 

At any rate, it turns out that the Liverpool metropolitan population is pretty much the same as it was at its peak in 1931 (depending where the local borough boundaries are arbitrarily drawn). It just begs the question: why are well educated and supposedly clever people misrepresenting the Liverpool metropolis, in particular, in this way so often? Surely they aren’t stupid are they?

And why are some people so determined to always isolate the City of Liverpool from its hinterland, while London is always described in terms of its whole urban area? It just confuses and undermines what would otherwise often be worthwhile comparisons and discussions. Or, to put it another way: “never, ever, compare apples with larger urban zones”.

In a recent Channel 4 documentary, for example, the well-known and respected journalist Michael Burke directly compared the forecast population growths, by 2039, of the City of Liverpool single local authority area against that of the combined 33 local authority areas of Greater London: 42,722 versus 2.187,708. I mean, what bizarre point is such an inappropriate comparison even trying to make? It is like comparing the projected growth of a normal sized-person’s head with the projected growth of the whole of an obese person, over a protracted period.

Having said all that, there is an important sensible conversation to be had as to why the populations of the Greater Liverpool metropolis and others haven’t grown as fast as maybe should have been the case, whilst, in recent times, the Greater London population has been burgeoning. But constantly pitching it as some sort of rare local apocalypse helps no one.

Dave Mail has declared himself CityMetric’s Liverpool City Region correspondent. He will be updating us on the brave new world of Liverpool City Region, mostly monthly, in ‘E-mail from Liverpool City Region’ and he is on twitter @davemail2017.