How and why does a scientist like me study the gas methane? The 'why' part of the question is often easier to answer than the 'how' part so I'll answer that first.

Methane, like carbon dioxide, is an important greenhouse gas but it differs from the more widely reported CO₂ in a couple of important ways.

Firstly, methane is more powerful at trapping the suns rays. As a greenhouse gas it is actually more than 20 times as powerful as CO₂.

Vince collecting samples.

[photo © copyright Vince Gauci]

The second important difference relates to its lifetime in the atmosphere: methane lasts around 10 years in the atmosphere where as CO₂ can stay in the atmosphere more than 10 times as long.

The relatively short lifetime of methane means that atmospheric concentrations of the gas, and therefore its contribution to the greenhouse effect, is sensitive to short-term changes in sources and sinks of the gas. These sources include natural wetlands, rice paddies, land fill and cow burps.

The other key reason for studying methane is that over the past century, the concentration of the gas has been increasing - although in the past decade the pace of this change has been decreasing and, until a very recent rise was reported, had almost halted.

The reasons behind this pattern of growth are important to understand so that we can improve predictions of climate into the future.

Collecting methane samples in Flitwick.

[photo © copyright Vince Gauci]

I am interested in the controls on the emission of methane from the largest individual source: wetlands. Natural and artificial wetland ecosystems such at peat bogs and rice paddies produce methane as a consequence of anaerobic decomposition in saturated soils.

My work chiefly deals with chemical controls over the production of methane in these ecosystems and pathways the gas takes in making the transition from the soil to the atmosphere. Much of my work has examined the effect of sulfur pollution in acid rain on the emission of methane from wetlands and rice paddies.

This is important because methane emitting wetland areas receive sulfur pollution via long-range transport of pollution. They also get sulfur from a natural form of pollution – volcanic eruptions.

The sulfate component of acid rain pollution is thought to stimulate one set of microbes that then out-compete methane-producing microbes for food. The result is a reduction in methane emission, and this seems to be sufficient to offset the growth in wetland methane emissions that would be expected to result from global warming.

We've also investigated the effects of a large Icelandic volcanic eruption that deposited sulfate over a wide area of the northern hemisphere in 1783 and 1784 and found that changes in atmospheric methane concentration at the time, as recorded in ice-cores, are consistent with our understanding of how sulfur pollution affects the wetland methane source.

My other interest is in novel pathways for anaerobically produced methane to leave saturated soils and get into the atmosphere. Until recently, methane was thought to leave soils through diffusion, bubbling or through the hollow vessels of wetland adapted herbaceous plants like sedges and rushes.

In recent studies we've found that wetland trees contain some of the same adaptations as sedges that enable them to survive in sodden soils and this enables mature trees to emit methane from their trunks – an important finding given that many of Earth's wetlands are forested.

Together with a team of PhD students, we shall be going to the Kalimantan peat swamp forests of Borneo in early 2009 to investigate whether tropical wetland trees in Borneo are also functioning in the same way.

Find out more

Stephen Self explains why the 1783 Icelandic eruptions affected the whole of Europe.

Discover the routes into studying science with the Open University.

Explore more Open University research with BBC Radio 4's The Material World.

About the author

Vince Gauci was appointed Open University lecturer in Earth Systems and Ecosystem Science in November 2004. He is a member of the Department of Earth and Environmental Science Biogeochemistry group, which in turn is part of the cross departmental and cross faculty Ecosystems Research Group.
Browse a list of Vince Gauci's published research.

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Since my early visits to India in the mid 1990s it is true to say that there has been something of a revolution in air quality in many of the cities here. In my last blog I mentioned the Taj Mahal. Vehicles are now banned from within 0.5 km of the fragile marble structure lest pollution destroys its beauty. This ban is complete and even the surrounding lawns were being cut by oxen pulling an industrial sized mower, instead of the usual noisy and dirty petrol-driven contraptions.

Polluting vehicles are banned from the Taj Mahal, so mowing green is the order of the day.
Photo © copyright Bob Spicer

However in Delhi in 1998 I remember literally choking on black soot-laden air in the evening rush hour. Most of the pollution was coming from the small three-wheeled autorickshaws or “tuk-tuks”. These ran on low-grade fossil fuel that was inefficiently burned in unsophisticated engines. Now all that has changed. In a draconian move, at the time unpopular but necessary, such vehicles were banned from the road across India and replaced with tuk-tuks running on compressed natural gas (CNG). This burns cleaner without the sooty particulates and can be made from renewable sources such as farm waste.

In Agra I saw what must have been close to a hundred tuk-tuks waiting in line to be filled with CNG. These vehicles, and their slightly larger cousins the Vikrams (which also run on CNG) provide a valuable public service in that for the modest sum of around 8 rupees (approximately 10p) you can be taken across town some 4km. This is often an exciting ride dodging in and out of the traffic, going the wrong way up dual carriageways and careering around the inevitable cow, buffalo or even elephant. However in a Vikram almost always you are sharing the experience with up to ten others crammed into a space about the size of the interior of a smallest of UK family cars - friendly, but very efficient.

Upon my return to Lucknow I went to the BBC News website to catch up on world events only to find an email there from someone recently returned from India. They had been stunned by the apparent road chaos here and complained that any attempt by the government to encourage “green” behaviour in the UK would be entirely negated by traffic growth in countries like India.

This is an often-used excuse for us in the more affluent parts of the world to do nothing in respect of tackling climate change. However it betrays a misunderstanding of the nature of traffic here. In India per capita private car ownership is a mere fraction of what it is in the UK, the cars are, on the whole, much smaller, and the vast majority of vehicles are, like the tuk-tuks and Vikrams, public service vehicles.

In Lucknow at least 20% of road vehicles are pedal rickshaws operated by farmers who rent the rickshaws by the day for around 30 rupees and make a living between sowing and harvesting taking people around the city in a low pollution, low carbon, way. Scooters and small motorcycles also abound. Although not very clean, they have a far better fuel consumption than the average UK car which on the commute runs tend to carry only the driver.

To be sure, as the Indian economy grows the car manufacturers will do their best to encourage the new Indian affluent to indulge their fantasies of the great green outdoors by driving all over it and destroying it further. TV ads here show a big, bright, shiny 4x4 charging across pristine wetland wilderness churning it into a quagmire, all in the name of appreciating “the environment”.

If only one in a hundred Indians bought such a vehicle, and did as the ads suggest, it would mean 10 million of them trashing the countryside. The antisocial consequences of owning such vehicles for purely leisure purposes, whether in the countryside or in towns (where, if you are interested in going anywhere, or even parking, small is practical), are becoming obvious here just as they are in the UK.

In cities and towns like Lucknow the smart money is on the status quo in that it represents high fuel efficiency per capita and low cost. However things are far from perfect. If only people here would obey some kind of highway code things would operate even better. As it is, it appears to be the one in front who has the right of way and it seems that nobody ever signals, looks left, right, or in their mirror before manoeuvring! At times it just seems like survival of the fittest.

About the author

Bob Spicer is Professor of Earth Sciences at the Open University. Founding Director of the OU's Centre for Earth, Planetary Space and Astronomical Research (CEPSAR) his interests are broad. However he is most at home when studying how plants can be used to tell us about ancient climates, and how that information can help us plan for managing our planet in the future.

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