Environmental Engineering Reference
In-Depth Information
available to reduce emissions for the air sector. Many of the planes flying today will still be
in use in 2025 and even 2050 (for example, the A380).
The only way to reduce emissions is therefore to reduce demand - through pricing, regulation
and even rationing - and there is little political (or public) appetite for these policy levers.
Even with the wide range of measures to tackle emissions in ground-based transport as
suggested in Scenario 4, and including a 'medium' reduction in the projected growth in air
travel (a 10 per cent reduction against BAU), the calculations are that the reductions in CO2
emissions fall to just 23 per cent (relative to the previous 60 per cent reduction in Scenario
4). The scale of emissions involved in air travel thus becomes very important.
There are further areas that are important to carbon efficiency in transport, but remain very
poorly understood and developed. These might be termed 'enabling mechanisms'. The first
is carbon rationing (Hillman and Fawcett, 2004) - there are a number of possible ways of
implementing a rationing scheme in the transport sector. The most likely are through car
manufacturers, fuel suppliers or as personal carbon allocations (PCAs). Each would involve
a cap and trade system with an overall maximum total level of emissions, probably reducing
in volume over time. This cap and trade mechanism might help achieve high-intensity
application in the preceding packages. But there are very large implementation difficulties,
particularly with PCAs (Department for Food and Rural Affairs, 2008; Environmental Audit
Committee, 2008; Fawcett and Parag, 2010). There is, however, one related example of
implementation. The EU Emissions Trading Scheme (EU ETS) is already running, where
some major polluting industries are allocated tradable emission permits, and they can use or
trade them according to the levels of CO2 produced. The transport sector is likely to be included
in this scheme in future years, with international air emissions also being included. The idea
is to set a cap on the aggregate level of emissions and trade within this level. Trading is likely
to be at the business and/or national level. Much uncertainty, however, remains as to how to
implement a trading mechanism for carbon.
One argument for including aviation in the scheme is that, as flying is a premium producer
of CO2, the aviation industry would buy all available permits and then pass on the costs to
the users. The additional costs would reduce the demand for air travel and would allow other
industries to decarbonise at a faster rate. At present (2013), there is a delay in including
aviation into the ETS as the airlines have undertaken to come up with their own scheme. The
EU has given them a year to do this, as a result of intense pressure from international airlines
and national governments against any form of charge on aviation CO2 emissions.
Second is oil price (and linked with the 'peak oil' debate). Over the past 30 years there
has been some stability in oil prices - at relatively low levels - but recently this has changed,
with high volatility and some concern we are reaching, or have already reached, a period of
peak oil (Strahan, 2007; Heinberg, 2003). This is likely to result in dramatically higher oil
prices as suppliers and consumers react to perceived supply shortages. The consumer is shielded
to a certain extent by the high tax component in the price of petrol and diesel. Nevertheless,
a large increase in the cost of oil impacts markedly on the price of petrol and diesel. Large
price increases are likely to dampen the demand for travel using oil and provide clear signals
to industry and consumers to increase efficiencies.
Recent price volatility may have an important impact on travel demand (in early 2013 Brent
crude oil prices were at around $110 per barrel, and hit $140 per barrel in July 2008). The
typical elasticity used for vehicle travel with respect to fuel price is assumed to be in the order
of -0.15 in the short run and -0.3 over the long run (Graham and Glaister, 2002). Recent
price rises, we would expect, should be feeding through to reduced demand for travel, and
this may be acting as an effective enabler of reduced carbon dependency in travel. There is
