There were a few wry smiles in the BusinessGreen.com office yesterday morning when we read the report that a Japanese airline was requesting passengers take a toilet break before boarding an aircraft in an attempt to reduce weight and cut in flight carbon emissions.

All Nippon Airways (ANA) has apparently calculated that with a full human bladder weighing about 1kg it may be possible to strip out a fair few kilograms by reminding people to take a few moments to relieve themselves before they get on the plane.

Leaving aside the fact that only someone with a bizarre airline toilet fetish would need a reminder to make sure they were, shall we say, comfortable before they got on a plane, the question has to be whether this policy constitutes anything more than a vaguely amusing publicity stunt?

There is no doubt that lightening the load of an aircraft through any means will help reduce fuel use, but equally the impact of leaving a few unnecessary kilograms in the airport's facilities will have an infinitesimally small affect on fuel efficiency.

More significant are ANA's plans to reduce the weight of in flight materials, such as cutlery and glasses, and request that passengers not bring unnecessary luggage. A number of airlines, such as Emirates, have already scrapped in-flight magazines in an attempt to cut down on weight, while budget airlines such as Ryanair and EasyJet have long kept fuel costs down by keeping their aircraft as light as possible.

But the question remains as to whether even these fuel savings are worth while. Small savings will add up when spread across an entire fleet, but is attempting to cut aviation's carbon emissions by shedding a few unnecessary pounds a bit like trying to bail out the Titanic with a thimble.

Professor David MacKay the newly appointed chief scientist at the Department of Energy and Climate Change who has been encouragingly prone to contentious remarks during his short time in the post, has been at pains to point out that focusing on minute, incremental cuts in carbon can distract from the sheer scale of the transformation that is actually required. As he observes, "if we all do a little, we'll achieve only a little".

There is validity in this argument, in terms of their carbon savings small scale measures are not far short of a waste of time. As MacKay's already famous calculations show, the carbon saved by turning off your phone charger each day is equivalent to driving your car for one second. Even when multiplied across an entire economy savings on this scale will never get us anywhere near the kind of carbon emission reductions that are required. The only way to really decarbonise the economy is to develop an entirely new low carbon energy and transport infrastructure that strips the emissions out of every aspect of our day-to-day activities.

But direct carbon savings are not the only factor to consider when looking at micro-scale improvements in efficiency - there is a psychological element at play as well.

I recently interviewed David Halford, head of ethical sourcing and environmental policy at BBC Worldwide, about the company's green initiatives and while he was under no illusions as to the importance of large scale carbon reduction projects he also argued that small scale initiatives had a key role to play.

Most notably, he revealed that the company had moved to get rid of disposable plastic cups, despite the fact that a lifecycle analysis comparing disposable cups and ceramic mugs had shown that the carbon savings were pretty negligible. "Every time we had a meeting we had with staff about environmental issues someone would bring up the need to get rid of the plastic cups," he explained, adding that getting rid of the dreaded cups had removed a layer of resistance and freed the environmental team get on with more ambitious measures.

The same phenomenon applies to turning off phone chargers and perhaps even visiting the toilet before getting on a plane. The carbon savings might be minimal, but ensuring people are conscious of energy use and reminded to reduce it where possible can only help secure support for more demanding initiatives.

You could argue that promoting these micro-scale measures can lull people into a false sense of security, but equally they can serve to pave the way for the kind of more ambitious projects that are required. After all, it is not such a big leap from asking people if all their luggage is necessary to asking them if their flight is necessary.

Perhaps the old adage is right after all, every little does help.