Turning the land from an emissions source to a carbon sink

Posted on July 13, 2011 by admin

Corinna Byrne

Farming and other land-based activities could do a lot to mitigate global warming. Ireland needs new policies to get its land to absorb CO2 rather than release it. The large amounts of carbon locked up in the country’s peatlands must be safeguarded and damaged bogs restored so that they can sequester carbon again. In addition, the use of biochar could reduce methane and nitrous oxide emissions and build up the fertility and carbon content of the soil.

Climate change is the most pressing problem of our time and one to which we all contribute in varying degrees. Those working on or closely with the land can do a lot to improve the situation. At present, their activities, especially in agriculture, contribute significantly to global warming by adding not just CO2 but also methane and nitrous oxide to the atmosphere. However, if policies were adopted which refocused the purpose of the land and the right methods were used to manage the different greenhouse gases (GHG), agriculture could be transformed from being a source of emissions to a sink.

In order to explore what these policies and methods might be, Feasta set up the Carbon Cycles and Sinks Network (CCSN) in late 2008 with funding from the Irish Department of the Environment, Heritage and Local Government, which wanted advice on policies it could adopt to reduce GHG emissions from land-based sources in Ireland. The Network enables people with specialist knowledge of these emissions and ways of reducing them to help identify and develop the policies put forward.

Irish land-based emissions are the largest in the EU in relation to its other emissions so it is in Ireland’s interest to take a lead in developing EU policy in this area. Accordingly, the CCSN has not restricted itself to developing national-level policies but is also advancing approaches that Ireland could promote at EU and possibly at UN level. We have concentrated on what can be done to reduce emissions from the most important land activities: deforestation, the management of agricultural soils and the raising of livestock.

We consider that Irish climate policy should be developed on the basis that temperatures must be prevented from rising by more than 2ºC and even that figure is probably too high. The Intergovernmental Panel on Climate Change (IPCC) 4th Assessment report says that achieving the 2ºC target means stabilising GHG concentrations at about 445 to 490 ppm carbon dioxide-equivalent (CO2-eq). This corresponds to about 350 to 400 ppm of CO2 alone. Ireland should therefore press its EU partners to negotiate for a concentration target of 350 parts per million of CO2 by volume or less. Four eminent climate experts — Nicholas Stern, James Hansen, John Schellnhuber and Rajendra Pachauri — have all indicated that a target of 350ppm or less is required. The 350 level was passed in 1987 and, at present, the atmospheric concentration is around 390 and is rising by about 2 ppm a year. Returning to it means that all current emissions must stop and, at the very least, all the CO2 released since 1987 that remains in the air must be recovered.

At present, only land plants can be considered to be natural atmospheric carbon extractors as current scientific evidence indicates that the fertilisation of the ocean will not significantly increase carbon transfer into the deep ocean and thus lower atmospheric CO2 [1]. In view of this, CCSN concentrates on land-based carbon sequestration and aims to develop policies that should lead to the land taking up and holding more carbon.

Reducing and sequestering carbon dioxide emissions

Terrestrial ecosystems store about 600 billion tonnes of carbon in living organisms and decaying material and 1,500 billion tonnes in soil organic matter. The total, 2,100 billion tonnes, is almost three times the 750 billion tonnes currently in the atmosphere. Consequently, if fossil and land-based carbon emissions stopped today, reducing the atmospheric concentration of CO2 from 390 to 350 ppm would involve increasing the amount in plants and soils by 77 billion tonnes or about 3%.

Of course, fossil- and land-based carbon emissions cannot be stopped immediately. Fossil-fuel combustion will release about 29 billion tonnes of CO2 this year. If that release rate was phased out over 40 years on a straight-line basis, a total of 580 billion tonnes would be released before emissions stopped. Deforestation is releasing perhaps 7 billion tonnes a year. If it proves possible to stop that in ten years, it will add 35 billion tonnes to the atmosphere by the time it ceases. So, if other GHG emissions are ignored, 615 billion tonnes of CO2 will be added to the atmosphere by 2050. This converts to 166 billion tonnes of carbon. Adding that to the excess carbon already in the air means that the amount of carbon held by plants and soils needs to increase by over 11%.

Each year’s flow of carbon into and out of the terrestrial stock is huge, as Figure 1 below shows. It would only be necessary to reduce the outflow and/or increase the inflow by a small amount each year to achieve the 11% increase in the terrestrial carbon stock over, say, the next 50 years.

Figure 1: Annual carbon fluxes into and out of the atmosphere

Increasing above-ground biomass (AGB) by planting could do much more than take carbon out of the air. It could, for example, provide all the energy currently provided by fossil sources by 2035. It could also sequester 13 billion tonnes of atmospheric carbon a year, well above the 1 billion tonnes required to ensure that the 350 target is not exceeded by the end of the century [2]. It would also provide food. In addition, there is a strong possibility that the transpiration from the new growth would increase cloud cover and thus have a cooling effect. On the other hand, it would change much of the Earth’s surface but in a more benign way than a runaway warming.

Several policy conclusions inevitably follow from the adoption of the 350-or-less target. The discussion focuses on those directly concerning land-based emissions.

The Carbon Maintenance Fee

Rewards should be offered for holding and sequestering carbon and penalties imposed for carbon releases. All countries, not just developing ones, should be paid an annual carbon maintenance fee for maintaining each tonne of carbon in their soils and biomass as well as a higher, once-off reward for every tonne by which the stock is increased between one assessment and the next. It will not be possible for the average reward to be as large as the price being charged for the right to release a tonne of CO2 when fossil fuel is burned. This is because a large part of the revenue collected by governments or an international agency when emissions rights are sold will have to be recycled under an arrangement such as Cap and Share so that the poorest people in the world are not priced out of the market for energy as its price rises due to the artificial scarcity caused by a rapidly tightening cap. Governments that allowed their terrestrial carbon stock to decline should be required to pay a price based on the price of a fossil carbon emissions permit but with an allowance for the inevitable imperfections in the accuracy of the data in comparison for that from fossil-fuel use.

The carbon maintenance fee (CMF) would be paid in recognition of the fact that countries with forest or peat bog could potentially use that land in more immediately lucrative ways and that they therefore need to be rewarded for passing up those opportunities and retaining it as a carbon store. There are practical reasons for introducing a CMF too. For example, no government is going to like paying the charges involved if its terrestrial carbon stock is reduced. However, if the international agency levying the carbon-loss charge was also paying the government a carbon-maintenance fee, the deduction would be automatic.

Rewarding countries that increased their terrestrial carbon would put a very high value on maintaining forests. The Stern Review gives a figure of up to 1,000 tonnes of CO2 being held in a hectare of standing trees. At $25 per tonne of CO2 — a figure which is likely to be far below the price that users are likely to pay for the right to burn fossil fuel — the penalty for clearing the trees would be $25,000 less the value of the harvested wood. Stern gives a figure of up to $1,035 per hectare for the income from the sale of the wood and says that the cleared land, if it were to be used for high-value crops such as soya or palm oil, would be worth $1,000 per hectare. If his figures are correct, the penalty the state suffers for allowing the land to be cleared would be ten times the amount the landowner would get from going ahead with the clearance. This should be enough to make the payment effective, particularly as tropical forest can be expected to take in carbon each year.

A 2009 report [3] on the results of monitoring around 70,000 trees in ten African countries for 40 years shows that for at least the last few decades, each hectare of intact African forest has trapped 2.2 tonnes of CO2 per year. If the reward for each tonne of CO2 sequestered by this natural sink was 25, ($32) the government responsible for the forest could expect to be paid about $70 a year per hectare in addition to the carbon maintenance fee. When the researchers combined their African data with earlier figures from South American and Asian forests they calculated that tropical forests remove about 4.8 billion tonnes of CO2 from the atmosphere every year, about 18% of the annual amount added by burning fossil fuels. African forests alone account for 1.2 billion tonnes. That could give the countries that have them an annual income of perhaps $38 billion plus a carbon maintenance fee. As sub-Saharan export earnings in 2007 were $268 billion if South Africa is excluded, that is a significant sum. The forestry chapter in the IPCC’s Fourth Assessment report quotes an estimate that at around the $25 figure (it actually uses $27.2 per tonne) “deforestation could potentially be virtually eliminated.”

As for the CMF itself, if it were paid on all the 2,400 billion tonnes of carbon in the Earth’s biomass and soil, the rate per tonne would be very low. Suppose just ten US cents per tonne of carbon was paid, which works out at 37 cents per tonne of CO2. This would mean the annual payment for keeping the carbon in the 1,000 tonnes of CO2 per hectare of forest mentioned by Stern would be $370 per year. The total transfer of resources involved (it would be a mistake to think of the payment as being a cost) would be $240 billion. This compares with the 2009 GWP of $70,000 billion. In other words, the transfer would involve about 0.3% of the world’s incomes, which would seem to be an affordable sum.

Other ways of rewarding countries for forestry planting under offset arrangements should be ended. Offsets enable fossil-fuel users whose emissions are controlled by a cap to exceed their emissions limit by reducing emissions in a country outside the cap. As a result, offsets do not reduce emissions. Because a reduction in one place justifies extra emissions somewhere else, the best they can do is to stabilise them. But, according to FERN, the Forests and the European Union Resource Network,

even this best-case scenario appears to be rare as it is not possible to verify whether any claimed reduction would otherwise have occurred. By allowing the release of extra emissions without the certainty of equivalent extra reductions elsewhere, any trading scheme involving carbon offsets may increase rather than reduce GHG emissions. On top of this, many of these projects also affect the rights of some of the world’s poorest communities, resulting in increased hardship and suffering [4].

In any case, because of the massive effort required of the land-use sector if it is to become a net sink and absorb the excess CO2 in the air, it’s unlikely to have the additional capacity to absorb the fossil-fuel CO2 emitted under offset arrangements as well. Moreover, if, as suggested above, a global emissions cap was put in place, offsetting would be unnecessary since, if a country or a company wished to emit more than it had been allowed, it would simply buy the permits to do so from a country or company with a surplus.

EU policy maintains that tropical deforestation should be reduced by at least 50% by 2020 compared to current levels, and the global forest cover loss should be halted by 2030 at the latest. Ireland should press for each of these targets to be brought forward by five years. The EU has failed to challenge the REDD approach of paying countries for the emissions they avoid by clearing forest at a slower rate than in the past. It wants to fund REDD by using voluntary contributions from rich-country governments to cover “readiness work and capacity building,” with the bulk of the remainder coming from offsetting via the sale on developed-country carbon markets of carbon credits covering the avoided emissions.

However, the EU is worried that these sales could undermine the carbon markets by overloading them with credits to such an extent that the carbon price falls and no longer acts as an incentive to developed countries to curtail their emissions. As a result, it has suggested a separate market for REDD credits. It’s not clear how this would work but the idea of keeping the two markets apart as a temporary measure until a global cap is in place is in essence a good one as it would prevent the land being used to offset current fossil emissions rather than having the task of removing the excess of CO2 already in the air.

The EU is also concerned about the possibility that carbon credits will be issued because trees are not being cut down at the previous rate in one part of a country while forests are being cleared faster in another. It therefore wants a whole-country approach to be adopted to prevent this “leakage”, something that might only be possible if remote-sensing measurements are used. Ireland should urge its EU partners to reject offsetting via REDD altogether or to tighten the limits on how much can be done with a view to phasing it out completely by 2020. Funding for whole-country REDD schemes should be come from the proceeds of auctioning EU emissions trading system permits (EUAs) after 2012 until a global system can be put in place.

Using remote sensing for carbon-emissions reporting

Because adequate whole-country measurement methods were not available when the Kyoto Protocol mechanisms were devised, the rich, high-emissions countries which signed up to it — collectively known as the Annex 1 countries because that is where their names are listed — had no option but to take an activities-based approach to measuring, reporting and accounting for their Land Use, Land-Use change and Forestry (LULUCF) emissions. Because this approach looks solely at the emissions that result from an activity such as planting or clearing trees and assumes that everything else is unchanged, it has allowed a lot of gradual changes to be ignored. Consequently, now that remote sensing techniques are being developed to enable all the emissions and emissions absorption from a country’s entire land area to be estimated with reasonable accuracy, Ireland should move towards land-based LULUCF measuring and reporting using remote sensing techniques. It may be possible for the country to achieve Tier 3, the most accurate and detailed level of emissions reporting, on this basis.

The two main types of remote sensing, Synthetic Aperture Radar (SAR) and LIDAR, can be used together and in conjunction with optical and infra-red images. SAR has been used to map ABG since the 1960s. Microwave pulses are sent out and the amount of that energy reflected back to the sensor is recorded. As it uses radar, it can operate day or night through haze, smoke and clouds. The microwaves penetrate forest canopies and the amount of backscattered energy can reveal a lot about the trees’ leaves, branches and stems. Rather than microwaves, LIDAR sends out pulses of light from a laser. This means that it cannot penetrate cloud. However, it has an advantage in that it can measure the three-dimensional vertical structure of vegetation in great detail. It has revolutionized the way vegetation is measured from satellites, but for forestry operations, aircraft-borne sensors are used. A 2009 assessment [5] of remote sensing techniques by a team from Woods Hole concluded

Satellite data enable reliable mapping of carbon stocks over large areas… This situation will improve further as new satellite missions come online in the next few years, several of which are designed specifically with the intent of improving estimates of the standing stock of carbon in biomass, and changes in those stocks through time. The UNFCCC process would benefit from refinement and application of these approaches and from improved data in developing policies designed to reduce emissions from deforestation and forest degradation.

With remote sensing, a country could report and account comprehensively for everything that affects the types of land that, like pastureland, forests and bogs, can be either a sink or a source depending on management methods and the climate itself. This is particularly important because rising temperatures and altered rainfall patterns will play a large part in determining whether land releases carbon or takes it in.

At present, under the Kyoto Protocol’s Article 3.4, Ireland can choose to operate on Tier 2 and account for carbon gains and losses from forest management, cropland management and the management of pasture land. So far, Ireland has not accounted for these carbon gains and losses, mainly for lack of data, and operates on Tier 1, which uses default figures rather than country-specific ones to estimate emissions. To use Tier 2, for example, cropland and grazing land management require data going back to 1990. However, this data requirement would disappear if a switch was made to remote sensing as it would no longer be necessary to establish a trend line and estimate changes in the trend. All that would be necessary would be to use an aircraft to carry out a baseline LIDAR survey that was calibrated by on-ground sampling. The sampling would measure AGB, below-ground biomass and soil carbon. Leaf litter and deadwood could also be included if desired. The aerial survey would then be repeated regularly at the same time each year and a calculation carried out to establish the carbon gained or lost.

If the EU adopted remote sensing for its emissions returns it could pilot its use by the rest of the world at a later date. The adoption is likely to save money. Not only is it cheaper to gather the required information by remote techniques but New Zealand has also found that it can recover the cost about 22 times because it ensures that country’s eligibility to offset GHG emissions above the 1990 level of emissions and to participate in international carbon trading.

At least some of the revenue each member state received for holding and, in some cases, increasing the biomass and soil carbon stock should be used by the state to encourage further increases in the carbon held. A system of rewards to individual landowners would be impractical because of the difficulty of measuring soil carbon with sufficient accuracy, especially as the remote-sensing results are optimised to show changes from year to year rather than exactly what was on the ground when the over-flight took place. As a result, Teagasc, the Irish Agriculture and Food Development Authority, suggests that a new definition of best farming practice be devised and that the adoption of this be incentivised by the programme that is being developed to replace the Rural Environment Protection Scheme (REPS). This could include activities that lead to lower agricultural emissions and the increase in carbon in biomass and the soil. CCSN has been asked to help devise this “Carbon REPS.”

Irish land-based emissions: a three-gas problem

In global warming terms, carbon dioxide is not the most important GHG produced by activities on Irish land (see Figure 2 below). Methane produced by the national livestock herd is more serious, accounting for 45% of the land-based warming effect. CO2 makes up 32% and nitrous oxide 23%. Moreover, the CO2 figure is only as high as 32% because the emissions from peat burning have been included, although, internationally, they would not be included in emissions in the LULUCF category.

Nationally and internationally, all three gases need reduction programmes and targets of their own and methane and nitrous oxide should not be bundled with CO2 as “carbon dioxide equivalents” with exchange rates set at their Global Warming Potential (GWP) in relation to CO2. The bundling approach tends to limit the priority given to reducing the emissions of each gas to the latest estimate of their GWPs whereas a more holistic view of a gas’s total climate and environmental impact is desirable, something that can only come from a gas-by-gas approach.

Figure 2 compares the ways the emissions of the three greenhouse gases produced by the way the land are used. Indirect nitrous oxide emissions are those produced when ammonia has escaped into the air or nitrates have been washed into rivers get broken down. Direct peat land emissions are the methane released by intact bogs and the CO2 released by bogs that have been disturbed. (Compiled by CCSN).

Reducing carbon dioxide emissions from peatland

Peatlands are Ireland’s largest stock of terrestrial carbon, storing an estimated 1.2 billion tonnes [6]. This equates to 4.4 billion tonnes of CO2 so, as total Irish GHG emissions were 67.44 million tonnes CO2 in 2008, the peatlands contain
7 times the carbon in the country’s annual emissions. Peat bogs and the fuel that is taken from them are also this country’s largest land-use source of CO2. They add perhaps 9.1 Mt or over 13% (there is no agreed figure) to the country’s total GHGs and there is therefore no alternative but to act to bring down the emissions they generate. There are two components to these emissions; the use of peat as a fuel and the release of CO2 from disturbed bogs, primarily as a result of the extraction of fuel. There is also the opportunity cost of disturbing bogs because the damage means they do not take up carbon from the atmosphere. In their intact or undamaged form bogs are the most efficient terrestrial sink for atmospheric carbon dioxide as their persistently high water table ensures that the carbon entering the system through photosynthesis is greater than the amount leaving as organic matter is broken down [7]. A crude estimate based on data [8] produced by a team led by Dr. David Wilson of University College Dublin that annual sequestration by near-pristine bogs in Ireland could be anything between 60,000 tonnes and 140,000 tonnes of carbon.

The Irish Environmental Protection Agency’s National Inventory Report 2009 shows that in 2007, the burning of peat was responsible for 7.6% of the country’s fossil-fuel emissions but provided only 3.6% of the fossil energy actually used. It is therefore a very inefficient fuel in CO2 terms. To this must be added the emissions caused by extracting the peat. Draining a bog so that extraction can begin turns land from a CO2 sink to an emissions source. This is because the fall in the water table allows air to get to the peat and start oxidising it, so that the carbon in it slowly disappears. There is no specific Irish data for these releases but if Finnish figures are applied to Ireland, Bord na Móna’s bogs alone are responsible for the release of 454,400 tonnes of CO2 each year. This compares with the 2,700,000 tonnes of CO2 released when the fuel that it supplies to the power stations was burned. It can therefore be said that extraction adds at least 17% to the combustion emissions from milled peat. Estimates of the releases from bogs used for the production of sod peat amount to over 4 million tonnes of CO2 a year. If this figure is correct, as sod production amounts to an estimated 650,000 tonnes per year [9], sod peat production is especially emissions inefficient as, in addition to the emissions from the peat extraction, its combustion leads to 779,000 tonnes of CO2 being released. So for every tonne of sods burnt, over 8 tonnes of CO2 is emitted.

But peat is not only expensive in emissions terms, it is also costly in money terms when compared with other fossil sources, which is why its use for electricity generation has had to be subsidised in periods when the price of other fossil fuels has been low. A 2009 study, Burning Peat in Ireland by the Electricity Research Centre at University College Dublin, showed that electricity users subsidised peat-fired power stations by around 60 million in 2008 through the public service obligation (PSO) levy. To this must be added the value of the EU Emissions Trading System permits that the three stations had to be allocated so that they could burn the peat and which they could have sold if the fuel had not been used. If a price of 25 a tonne of CO2 is assumed, the 1.81 million tonnes of CO2 allocated [10] would have a market value of 46 million.

There are three peat-burning power stations in Ireland. The main reason for building them was energy security, the desire to have electricity from an Irish source that could be relied upon if there was ever any difficulty importing the coal, oil or gas required by the bulk of the country’s generating stations. The three stations are readily dispensable. When they are working, they supply only 6.6% of the electricity system’s demand. In the climate emergency situation we face, the energy security that peat provides must be achieved in some other way and peatland use must be refocused from energy to carbon storage and sequestration.

The extraction of sod peat for domestic use has damaged an estimated 46% of Irish peatlands [11]. The protection of peatlands is required by the EU Habitats Directive and by the Ramsar and Biodiversity Conventions. Ireland is legally required to maintain the area and range of these habitats as they were when the Directive came into force in 1992. Some effort was made in 1999 when over 160,000 ha of bog were designated as Special Areas of Conservation (SACs). At present, the SAC area is estimated to have risen to over 220,000 ha [12]. However, ownership of these sites remains largely in private hands and conservation depends on a management agreement between the state and the private owners [13]. This is not a secure basis for conservation as the integrity of the reserves remains partially dependent on the goodwill of the owners. Moreover, the state is not protecting SAC bogland as required by the directive. Thirty-two raised bog sites were designated in the 1990s as SACs under the directive. However, a ten-season derogation was granted in 1999 which allowed turf cutting to continue in the “protected” sites. In 2002, a similar ten-year derogation was given for raised bog SACs designated since 1999 and in 2004, an additional ten-year extension was given to allow continued digging on raised bogs designated as Natural Heritage Areas. Blanket bog conservation areas (SACs and NHAs) are effectively subject to an indefinite derogation. There is no provision in the Habitats Directive which allows member states to derogate in this way, and in this respect Ireland is in danger of being found to be in breach of EU law.

In order for Ireland to fulfil its climate obligations and those under the Habitats Directive, peatlands and the carbon they contain must be protected. In 2003, domestic turf cutting was going on in over 80% of the designated raised bogs. It is estimated that over 20,000 turbary rights exist on these bogs, of which over 2,500 were exercised in 2003 [14]. In 1999, the National Parks and Wildlife Service (NPWS) introduced a voluntary scheme to purchase turbary rights. This has met with very limited success and only about 5% of turbary rights have been purchased. This may be because the price available under the voluntary scheme, 3,500 per ha in SACs and NHAs, does not reflect the bog’s earnings potential for the landowner. It is said that a worked peatland can produce a profit of up to 1,000 per hectare per year [15].

So what is the solution? A greatly increased price would be needed to purchase turbary rights with this potential. Accordingly, an annual tax should be payable by the owner of every bog where turf cutting is being carried out or which has been drained so that it can be carried out. The tax would apply to all turf cutting, not just in protected areas. The amount payable for each site would be based on an estimate of the emissions released by the oxidation of the bog as a result of the drainage plus the emissions from the combustion of any peat dug.

It is reasonable to impose such a tax as emissions from peatlands are likely to be included in the returns that Ireland has to make to the EU in future under the Effort-Sharing Decision, and the country is almost certain to have to pay a cost per tonne to buy permits to cover its failure to meet the reduction target set for it. After the tax was in operation, the turbary rights to the protected sites, and probably the sites themselves, would be bought by compulsory purchase in cases where it had proved impossible to buy them voluntarily and the owners were not prepared or unable to restore the bogs to which they applied. The tax would obviously reduce each bog’s profit potential and thus the price paid for it, compulsorily or not. Moreover, the tax on drained but unworked bogs would encourage their restoration. If the government wished, the purchase offer, but not the compulsory purchase powers, could be extended to other peatlands.

The owners of any intact peatlands that remained in private hands after the tax had been imposed, and after harvesting in the protected areas had ceased should be paid an annual maintenance fee to reward them for the carbon they were keeping safe. The income for this, and for the purchase of turbary rights, could be paid out of the income that the state can expect to receive from the auctioning of EU ETS emissions permits after 2012. Alternatively, the Land Bond system, once used by the Land Commission to buy out the landlords, could be used to buy the turbary rights or the entire bog. The bonds would pay their registered owner a fixed rate of interest.

In addition to the threats to peatlands from peat extraction for energy, there are other threats, including extraction for horticulture, drainage for agriculture, afforestation and wind-turbine installation. All afforestation and planting on peatland and high-carbon soils should cease, wind-turbine installation should not occur on areas of peat and any peatland already taken into other uses should be restored if the carbon balance is favourable.

Reducing methane emissions from Irish farms

On a global level, the development of policies for the control and reduction of methane emissions is not helped by the fact that surprisingly little is known about the natural sources of methane, how long it persists in the atmosphere, the size of its warming effect in relation to carbon dioxide and what eventually causes it to break down. Figure 3 above is typical. It shows that emissions are estimated to have increased from 233 million tonnes of methane a year in pre-industrial times to about 600 million tonnes today.

Figure 3: The conventional view of methane sources, based on data from the Scientific American, February 2007. Wetlands are thought to be giving off more methane now than in pre-industrial times because of increased rice cultivation. The chart omits tropical forests, a large, recently discovered source.

Where does methane come from?

One of the biological sources of methane, are methanogens, single-celled micro-organisms that belong to a major division of life, archaea. These live in anaerobic conditions like those found in a stagnant pond or a cow’s rumen. After other micro-organisms have split any plant material in those environments into hydrogen and carbon dioxide, the methanogens use the hydrogen to turn the CO2 into methane.

Complexity of the methane problem

Uncertainty about how long methane stays in the atmosphere means that estimates of its warming effect as compared with CO2 have recently been revised twice. Half-life figures quoted in the literature range from seven to ten years. The atmospheric lifetime relates emissions of a component to its atmospheric burden and is 8.4 years for methane. In some cases, for instance for methane, a change in emissions perturbs the chemistry and thus the corresponding lifetime. The CH4 feedback effect amplifies the climate forcing of an addition of CH4 to the current atmosphere by lengthening the global atmospheric lifetime of CH4 by a factor of 1.4, making the estimate of its lifetime in the atmosphere is 12 years [16].

An important reason for this uncertainty seems to be that most methane [17] is broken down by combining with hydroxyl ions and possibly chlorine ions in the upper atmosphere to make CO2 and water. The hydroxyl ions are produced when the sun’s rays split an ozone molecule (O3) and each of the three free oxygen radicals that result joins with a water molecule to make two hydroxyl (OH) ions. If there are a lot of hydroxyl ions about, the methane is quickly destroyed but if a lot of methane is suddenly released, the supply of hydroxyls gets exhausted and the methane lingers on, continuing its warming effect. If this is correct, methane’s half-life is not a fixed number and, as a result, there is no fixed value for its warming effect in relation to CO2. The Intergovernmental Panel on Climate Change said it was 23 times worse until 2001 [18] but now prefers 25 [19]. What is beyond dispute, however, is that methane has a massive short-term heating effect that dies away as it gets broken down. Accordingly, reducing the amount released is a powerful way to have a big near-term impact on the rate the world is warming.

Emissions from the global herd of ruminants (cattle, sheep, goats and camels) contribute about one quarter of the methane production that is under human control and, consequently, consideration has to be given to reducing ruminant numbers. The UN Food and Agriculture Organisation is very concerned about this and produced a report in 2009 jointly with the International Energy Agency. The report, Belching Ruminants, a minor player in atmospheric methane, concluded:

Since 1999 atmospheric methane concentrations have levelled off while the world population of ruminants has increased at an accelerated rate. Prior to 1999, world ruminant populations were increasing at the rate of 9.15 million head/year but since 1999 this rate has increased to 16.96 million head/year. Prior to 1999 there was a strong relationship between change in atmospheric methane concentrations and the world ruminant populations. However, since 1999 this strong relation has disappeared. This change in relationship between the atmosphere and ruminant numbers suggests that the role of ruminants in greenhouse gases may be less significant than originally thought, with other sources and sinks playing a larger role in global methane accounting.

A bespoke approach to GHG emissions

In view of these uncertainties about methane, and in particular about its comparability with CO2, the Feasta Climate Group considers it unwise to have a single emissions-reduction programme, with a common target, for the two gases. It is therefore suggesting that Ireland should advocate the adoption of a non CO2–linked methane emissions cap-and-control programme at an international level.

Having a common carbon-equivalent price for all land-use emissions would present problems because each emitting activity releases two or three different GHGs and involves a number of sub-activities. Moreover, as I have just explained, the relative importance of reducing each gas cannot be adequately expressed through Global Warming Potential calculations. To achieve the desired result, it may therefore be better to have a number of policies and prices. Emissions from the raising of livestock should not be lumped in with those from, say, deforestation or fossil-fuel use and the same carbon, or carbon-equivalent price applied. A more suitable approach to controlling the release of enteric methane might be a separate national market for livestock emissions permits, linked by a common international cap. Any flow of permits from one national market to another should be controlled by the two governments and regulated by an international authority to ensure that sales did not mean that global emissions increased because land had to be cleared to accommodate the animals or they were to be fed in a different way.

Methane: the case for ruminants and other livestock

Amongst the livestock, it is the ruminants that produce most of the methane, both as a result of their digestive process and the way their dung is handled. It has therefore been suggested that, because the potential to reduce their methane emissions in any other way is limited, their numbers should be reduced in response to the climate crisis. However, for any such reduction policy to make sense, it would have to be done under a global cap that applied to all livestock, not just ruminants, to avoid a switch to pork and poultry production. Such a switch would mean a diversion of soya and grain that people could eat directly for animal food. Moreover, if the land area under crops being grown for animal food increased, it could mean increased emissions from deforestation, from the loss of carbon in the soil and from the nitrogenous fertilisers used. The global cap would also avoid production lost in countries which accepted the cap being made up countries which did not.

Ireland, working through the EU, should therefore seek to have global livestock numbers capped at their current level and to have the animal units allowed under the cap allocated to governments according to the number of animals kept in each country at present. Once a world livestock cap was in place, the international community would have the ability to control animal numbers. It could decide, for example, that the global herd was to be reduced by 10% over the next ten years. In this case, each government would be required to surrender 1% of its original allocation each year and a government that had grandfathered the initial allocation by giving them to farmers in perpetuity would have to go into the market and buy back enough of the permits it had given away.

However, it might be that the international community decided that no reduction in the global herd was required. This could be for three reasons:

  1. People want to eat meat and milk.
  2. There are no alternative farming enterprises in many parts of the world. Cattle represent the best way that some types of land can be used for food production. Livestock-based cultures need to be preserved and poor people need sources of income.
  3. The methane the herd produces does not build up in the atmosphere beyond the point at which the rate of its breakdown into CO2 and water equals the rate at which it is being produced. Moreover, the CO2 from the methane is not a net addition to the atmospheric stock as it was originally extracted from that stock by the plants the animal ate. Consequently, a constant global herd has a constant global warming effect rather than the cumulative one produced by the emissions from the burning of fossil fuels. The additional warming produced by the animals has to be set against the fact that pasture land takes CO2 from the air and sequesters it in the soil, where it will stay unless the land is ploughed. Moreover,, while animals can damage land and reduce the carbon it contains, they can also be used to improve it and to increase its carbon content. Allan Savory’s award-winning work [20] in Africa, the US and Australia has shown that if run-down land is very intensively grazed and trampled and then the animals are taken away completely until the grass and other plants have completely regrown, the land becomes more drought resistant and the amount of carbon in the below-ground biomass and the soil itself increases rapidly too.

The livestock sector is so complex and so important to so many poor people that it should not be expected to compete for emissions rights with fossil-fuel use. It is therefore suggested here that in terms of Irish policy, livestock emissions should become a new negotiating category alongside fossil-fuel and LULUCF emissions within the UNFCCC. Parties to the Convention should be asked to agree to the imposition of a global cap on livestock emissions and discussions should be held about the distribution of the emissions under the cap and the way they would be managed by national governments.

Agriculture is estimated to be the single largest contributor to Ireland’s GHG emissions (26.8% in 2007). This is unusual for a developed country but it’s much lower than in 1990 when it accounted for 35.9% [21]. The EPA believes that this reduction reflects the fall in nitrous oxide emissions due to less fertiliser being used, and a fall in methane emissions due to a decrease in cattle and sheep populations. In 2007 alone, there was a 3.8% decrease in agricultural GHG emissions. The continuing decrease in agricultural emissions is shown in Figure 4. According to O’Mara et al (2007) [22], about 49% of agricultural GHG emissions are methane from enteric fermentation in sheep and cattle. This would mean that ~13% of Ireland’s entire GHG emissions arise from this source alone. Of this, 91% is from the cattle herd. Since these emissions are currently included in the non-Emissions Trading System emissions, which the country has to reduce by 20% relative to their 2005 level by 2020 [23], ways of reducing these enteric emissions need to be explored.

Figure 4: Nitrous oxide and methane emissions from Irish agriculture have fallen continuously since 1998 as a result of the decrease in livestock numbers and lower levels of fertiliser use. Enteric methane makes up just over half of these emissions in warming-effect terms. Source: National Inventory Report, 2009 [24]

Table 1 gives the best current estimates of what might be achieved in reducing enteric methane emissions from livestock. If all the techniques could be applied in conjunction with each other, enteric emissions might be cut by about 5%. These estimates could still be highly inaccurate, and some depend on market conditions. The uncertainties due to a lack of whole life-cycle analyses could also be significant, notably the amount of nitrous oxide released when concentrates and additives such as dietary oils are grown. If the principle of internalising externalities is adopted, reducing methane emissions by any of the strategies listed in the table becomes theoretically profitable.

An effective methane-abatement policy should seek to raise emissions efficiency in relation to output rather than just cutting absolute emissions. At the current stage of research, the only feasible methane-reduction techniques are simple management strategies such as sending a beef animal for slaughter as soon as the average rate at which it is putting on weight begins to decline. These strategies could be part of the proposed Carbon REPS programme. However, a further reduction in the size of the nation’s herd or in milk and meat production must be opposed in the absence of a global livestock cap as otherwise “leakage” will occur.

Practice

State of development

Financially viable without payment for emissions saved?

Abatement possible
(% reduction in enteric methane)

Annual value of mitigated CH4 when CO2 is €25/tonne

Replacing roughage with concentrate for dairy cows

Being applied on farms

On a minority of farms

0.08

180,000

Replacing roughage with concentrate for beef cattle

Being applied on farms

Yes (with further research required)

0.79

1,790,000

Genetic improvement of the dairy herd

Being applied on farms

Yes

0.43

976,000

Improvement in milk yield additional to genetic progress

Being applied on farms

Yes

1.30

2,950,000

Genetic improvement of beef cattle

Being applied on farms

Yes

Lifetime management of beef cattle: halve number of cattle slaughtered over 30 months

Being applied on farms

Depends on market conditions

0.88

2,000,000

Lifetime management of beef cattle: increase number of young bulls slaughtered to 100,000/year

Being applied on farms

Depends on market conditions

1.0

2,270,000

Feeding dietary oils to beef cattle

Ready to apply on farms

Marginal

0.69

1,570,000

Feeding dietary oils to dairy cows

Establishing scope of measure (no programme currently in place to do this)

Propionate precursors for beef and dairy cattle

Ready to apply on farms

Not currently

Feeding maize silage to dairy cows

Establishing scope of measure (no programme currently in place to do this)

Feeding maize silage to beef cattle

Establishing scope of measure

Feeding other cereal silages instead of grass silage

Establishing scope of measure

Improved grazing management

Establishing scope of measure

Forage species and legume inclusion

Basic research stage/Establishing scope of measure

Probiotics

Basic research stage

Halogenated compounds

Basic research stage

Table 1: Summary of potential methane emissions reductions. Adapted from O’Mara et al. 2007 [25].

Reducing nitrous oxide emissions from Irish farms

The reduction of nitrous oxide emissions needs to be given much higher priority than even its high global warming potential, 298, and long life in the atmosphere, 114 years, would seem to warrant. It currently contributes 7.9% of the total anthropogenic warming effect. Its atmospheric concentration, 319 parts per billion in 2005, was estimated to be 16% above pre-industrial levels.

The reason for giving nitrous oxide much higher priority is that, now that emissions of chlorine- and bromine-containing chlorofluorocarbons (CFCs) and halons are declining sharply as a result of the Montreal Protocol, nitrous oxide is now responsible for destroying twice as much ozone as the next worst ozone-depleting anthropogenic substance, CFC-11, a refrigerant [26].

The destruction is damaging in two ways. Firstly, ozone filters out ultra-violet radiation coming from the sun, leading to an increase in skin cancers and cataract-induced blindness. Secondly, ozone destroys atmospheric methane. Consequently, an increased nitrous oxide concentration is likely to lead to an increased methane concentration and thus a greater total warming effect than from the nitrous oxide alone. It is not the nitrous oxide itself that destroys the ozone but two other nitrogen oxides, nitric oxide (NO) and nitrogen dioxide (NO2), which some of it becomes when the gas reaches the stratosphere, the second major layer of Earth’s atmosphere, between 10 and 50 km high. There, sunlight splits a fraction of it (~20%) into the nitrogen oxides via various reactions, while the major portion is converted to inert nitrogen gas (N2) [27]. Nitric oxide’s destruction of the ozone is catalytic — the gas is not itself broken up by the process — so one molecule can go on doing damage until it is either broken up itself or floats out of the ozone layer, probably to fall to earth as acid rain.

The destruction of atmospheric N2O in the stratosphere by photolysis and photo-oxidation is the only sink considered in global climate models. Very little seems to be known about other ways the gas is broken down, although two German scientists [28] working in a Norway spruce plantation in Bavaria recently found that long drought periods can turn the forest soil into a N2O sink, while wetting it turns it back into a source. The overall global balance between the sink function of soils and the source function is unknown.

Irish agricultural N2O emissions accounted for 9.9% of the country’s total GHG emissions and 37% of agricultural emissions in 2007. Fortunately, the prospects for reducing those emissions are much better than those of cutting methane. Significant reductions of around 20% nationally can be made immediately via:

  • Full adherence to the Teagasc Nutrient Advice. In general, Irish farmers still over-fertilise [29].The Teagasc Nutrient Advice 2008 [30], coupled with a soil nutrient test, is the primary source of information on optimum fertiliser amounts, taking account of current legislation (e.g. Nitrates Directive), plant-nutrient (including nitrogen) requirements as they vary over time and with soil and crop type, and the fertiliser-replacement value of land-spread manure.
  • Replacing slatted sheds with out-wintering pads. These have a purpose-built outside drained surface to replace slatted sheds for winter housing of livestock, and are becoming increasingly popular due to their lower cost (around 65%), completing the farm forestry cycle by using wood chips in its construction [31], and increased animal health [32].
  • Partial replacement of calcium ammonium nitrate with urea; on average urea causes 80% less N2O emissions than calcium ammonium nitrate [33], depending on soil and environmental conditions.
  • Adopting white clover-grass swards. White clover, a nitrogen-fixing legume, can be grown together with grass to add nitrogen to soil, replacing synthetic fertiliser and thus reducing fertiliser-induced N2O emissions.
  • Using only low-emission slurry spreaders. Most Irish cattle slurry is spread with a splash plate that results in high NH3 volatilization and NO3 leaching and hence indirect N2O emissions. The use of low-emission surface spreaders such as band and trailing foot/shoe could reduce NH3 volatilization by around 60% [34] and reduce the resulting indirect N2O emissions.
  • Separating slurry into liquid and solid fractions, and storing the latter as “solid storage”. Emissions from slurry fertiliser can be reduced by separating into liquid and solid fractions [35].

Cuts of a further 40-50% could be made if some or all of the following techniques were adopted:

  • The urea spread on pasture and arable land had nitrification and urease inhibitors added to it by the manufacturers. This adds very little to the cost and, because less nitrogen can be applied since less is lost, promises to save the farmer money. Inhibitors could also be added to slurry before it is spread.
  • More slurry was digested anaerobically. This would cut methane emissions as well. Inhibitors could then be added to the liquid digestate before it was injected into the land or the nitrates and the phosphates it contains could be secured by being taken up by biochar which would then be spread on the land.
  • Changes were made to animal diets, more cover crops were grown to take up the nutrients that might otherwise be lost if the land was bare between crops, and passing run-off water through a “bioreactor”, wood chips or sawdust — which absorbs almost all the nitrates it contains.

Policy should be focused on reducing nitrous oxide releases, taking in reductions in methane emissions whenever these are compatible, such as in the use of anaerobic digesters.

Biochar: A way to improve the soil as a sink?

The use of biochar is one of the few strategies that gives any basis for optimism that the excess CO2 in the atmosphere can actually be removed. Biochar is the charcoal produced when biomass such as wood, manure or leaves is heated in a closed container with no oxygen. This treatment is known as pyrolysis. A typical biochar sample is fine-grained and consists of between 50% and 80% organic carbon. Pyrolysis also produces a gas that may be burned to provide the heat the process needs and bio-oil, a liquid that may be upgraded to a liquid fuel.

The current world-wide interest in biochar stems from the possibility of using it to sequester carbon extracted from the atmosphere in a way that boosts a soil’s fertility. It does this by improving the soil’s ability to retain nutrients and water while simultaneously reducing the amount of methane and nitrous oxide it gives off. It is also claimed that including biochar in the soil boosts a symbiotic relationship by which the plants themselves increase the carbon content of the soil. They are said to do this by sending sugars through their roots to feed the fungi and microorganisms living in the soil in exchange for the nutrients that the micro-organisms release from the stock held by the biochar.

From a climate policy perspective, there is no point in supporting the application of biochar to the soil unless it can be shown to reduce GHG emissions and/or increase the carbon in the soil in addition to its own weight. It would be better to burn the biochar instead of coal if all that was achieved by applying a tonne of it to the soil was to sequester 600 kg of carbon.

The benefits claimed for biochar are:

  • Carbon will be sequestered in the soil
  • The crop yields from land to which biochar is applied will be significantly greater than those grown on untreated soil, increasing the amount of carbon sequestered by the biochar alone.
  • Because biochar locks up nutrients, less fertiliser is required and this in itself cuts emissions.
  • Biochar reduces methane and nitrous oxide emissions from the soil to which it is applied.
  • Biochar improves the soil’s water-retention capacity
  • The production of biochar could lead to the development of a network of rural biorefineries that turn biomass into energy, foodstuffs and chemicals as well as producing char.

Some of these benefits would go to the farmer, while the climate-related ones would accrue to the whole world. In deciding how much support the state or the international community should give to biochar use, a value needs to be put on both categories of benefit so that farmers pay for their benefits and, if a top-up is required to get biochar into use on the scale required to reduce the atmospheric concentration of CO2 as rapidly as required, the international community should pay the difference.

The International Biochar Initiative (IBI) has been campaigning for biochar use to generate carbon credits to offset emissions in Annex 1 countries. If this was allowed without careful and detailed planning and strict sustainability criteria in place and the value of the credits rose because of determined climate policies, the price put on biochar might rise so high that its production booms and becomes damaging. The level of demand might, for example, cause the clearance of natural forests and price the charcoal used for cooking out of the reach of the world’s poor. There might also be competition between food production and biomass-for-biochar growing for land. We therefore believe that at this stage, support for biochar should be limited to financing research and village-scale demonstration projects that utilize waste feedstocks, such as municipal solid waste, forest residues and agricultural residues, that do not compete with food and other land uses. In response to these fears, the IBI recommends that waste materials from agriculture and forestry should be “the primary near-term source of biomass feedstock for biochar production.” It writes [36]:

Large amounts of agricultural residues, municipal green waste and forestry biomass are currently burned or left to decompose and release CO2 and methane back into the atmosphere…. Using only 27% of the world’s crop and forestry wastes (the portion of wastes not currently used for anything else) for biochar, could by 2030 sequester 0.25 gigatonnes of carbon a year from biochar alone. If the energy co-product of biochar production is used to offset fossil fuel use, then the annual carbon mitigation potential of biochar more than doubles to 0.6 gigatonnes of carbon annually by 2030. A scenario utilizing 80% of crop and forestry residues shows that by the year 2050, approximately 2.2 gigatonnes of carbon could be stored or offset annually, reaching the gigatonne scale of carbon sequestration that is the benchmark for significant climate mitigation technologies.

Using waste material for biochar would avoid competition with food production and land conversion from forests to plantations. It would also create none of the pressure that forces indigenous people from their land. Furthermore, food security would be greatly enhanced by integrating biochar into food-cropping systems and turning crop residues into biochar for use on the farm.

Ireland’s efforts in the biochar arena should concentrate on research to demonstrate its effects in Irish soils and on developing a network of rural bio-refineries that would produce it as a by-product. This is how a local refinery might work. It could take in a crop such as miscanthus, crush it and extract the juice. These crops contain sugars and plant protein. The protein can be extracted and made into animal food and the remaining sugars can be anaerobically digested to create methane. That leaves the crushed stems, which are mostly cellulose. These could be pressure-cooked at 200 deg. in dilute sulphuric acid to break up the molecules into furans, levulinic acid and lignin, the glue that holds the plant fibres together. The lignin can then be charred and some of it heated with steam to produce hydrogen and carbon monoxide. These gases can then be mixed with the methane from the digester to give a synthetic natural gas that can either be piped to people’s homes, used to power an engine to generate electricity or compressed for use in cars. The furans would be transported to a regional refinery to become a diesel fuel. The levulinic acid would be sent away too as it is the starting point for a whole range of chemicals including nylon. Meanwhile, the remaining char would be used by the local refinery to purify the liquor coming from the digester. The char would tie up the plant nutrients it found there and would be put back on the land both to sequester carbon and increase fertility. Taking all these steps together, a whole new set of rural activities would be born.

For this vision to be realised, a detailed research programme for biochar is needed. This programme should do the following:

  • Identify and characterise potential feedstocks for biochar production from wastes, agricultural and forestry residues and energy crops.
  • Develop a classification system for biochars produced from different feedstocks.
  • Optimise pyrolysis technologies and operating conditions for different feedstocks and for biorefinery residuals.
  • Examine the stability of biochar in soils (lab-based trials, leading to field trials) to determine the changes that occur when biochars are applied to different soils. The most important parameters that affect stability for carbon sequestration, plant growth and the health of the soil need to be determined.
  • Investigate soil and plant growth improvement by biochar addition and the potential for fertiliser displacement.
  • Investigate the potential reductions in nitrous oxide emissions from fertiliser application through the use of biochar.
  • Investigate the potential human health implications from biochar production and application.
  • Develop a standard system for production of biochar from different feedstocks.

Conclusions

A number of measures are urgently needed to mitigate or avoid the worst effects of climate change. A separate reduction programme is needed for each major gas from each major source so that its special characteristics and the circumstances of its release can be taken into consideration rather than just its global warming potential. The four land-based programmes are:

  1. Enteric methane from ruminants.
  2. CO2 emissions from the clearing of forests, the extraction of peat and the conversion of land from one use to another.
  3. Methane from all non-enteric land-based sources.
  4. Nitrous oxide from all land-based sources.

It might be that the reduction programmes for nitrous oxide and methane could take in releases from all sources rather than just land-based ones but the implications of doing so need further consideration. However, in general, emissions trading between the different programmes, and thus different gases and different types of source, should not be allowed as that would effectively make them one programme and would dilute the priorities and the incentives being given for those with the highest urgency.

Table 2 below shows a summary of current land-based GHG emissions in Ireland and the possible emission savings to be made by implementing the reduction measures outlined in this report. Biochar does not feature in the table but it could play a significant role in carbon sequestration and emissions reduction besides bringing other benefits. A key aspect of its production is that it takes biomass that would otherwise have rotted away, dissipating the energy it contains, and the pyrolysis, besides making the char, turns the plant material into synthetic natural gas and diesel fuel and also into chemicals that are currently produced from oil.

If we are to survive the current emergency we need to look closely at how our land-based activities could mitigate global warming if we refocused their purpose. This will involve a serious re-think not only of policy and management methods, but also of our attitude and connection to the land. Land has always had a special significance for the Irish. In the future, it will continue to be important to us but in ways that are different from those at present. For the sake of our own health and that of the planet, we must use it well today if it is to be the resource we need it to be in the future.

 

Current Emissions

Possible Emissions Savings

Note

Peatland CO2

9.1 million tonnes CO2eq

(4 million from peat combustion; 5.1 million from peat oxidation)

3.2 million tonnes CO2eq

(>80% reduction)

4.6% of national emissions

Peat

oxidation

currently

ignored.

Peat cutting must stop.

Agricultural N2O

37% of agricultural or 9.9% of national emissions

1.4-3.4 million tonnes CO2eq

(20-50%

reduction)

2-5% of national emissions

 

Manure

Management CH4

2 Mt CO2e (14% of

agricultural emissions)

Estimated 75% reduction

2% of national emissions

More

research needed.

Enteric CH4

9 million CO2e (~13% national emissions)

Reduce by 450,000 t CO2eq (5% reduction)

0.7% of national emissions

National herd not

reduced.

Total

 

 

9.3-12.3%

(8.6-11.6%

excluding CH4)

reduction in

national emissions

 

Table 2: Summary of current land-based GHG emissions in Ireland and of possible emissions savings to be made by implementing the reduction measures outlined in this report.

Endnotes

  1. Surface Ocean Lower Atmosphere Study, an international research group based at the University of East Anglia, issued this statement in June 2007: http://solas-int.org/aboutsolas/organisationaandstructure/sciencesteercomm/sscmins/positionstatement.pdf
  2. Read, P. and A. Parshotam, 2007. “Holistic Greenhouse Gas Management Strategy (with Reviewers’ Comments and authors’ rejoinders)”. Institute of Policy Studies Working Paper 07/1, Victoria University of Wellington. Wellington New Zealand.
    http://ips.ac.nz/publications/files/6e811fc9e32.pdf
  3. Simon L. Lewis, “Making the Paper”, Nature 457, 933 (19 February 2009) ,
  4. “Reducing Emissions or Playing with Numbers?” Forestwatch no. 136, March 2009.
  5. Mapping and monitoring carbon stocks with satellite observations: a comparison of methods by Scott J Goetz et al, Carbon Balance and Management 2009, 4:2,
    http://www.cbmjournal.com/content/4/1/2
  6. Based on total island of Ireland. Tomlinson, R.W. 2005 Soil carbon stocks and changes in the Republic of Ireland. Journal of Environmental Management 76 (2005) 77–93; M.M. Cruickshank, M.M., Tomlinson, R.W., Devine, P.M. and Milne, R.1998. Carbon in the vegetation and soils of Northern Ireland. Proceed RIA.Vol. 98B, NO. 1, 9–21 (1998).
  7. Wilson, D., Alm, J., Laine, J., Byrne, K.A., Farrell, E. and Tuttilia, E.S., Rewetting of Cutaway Peatlands: Are We Re Creating Hot Spots of Methane Emissions? Restoration Ecology 2007
  8. Wilson, D., Tuittila, E.-S., Alm, J., Laine, J., Farrell, E.P., and Byrne, K.A. , Carbon dioxide dynamics of a restored maritime peatland, Ecoscience, 14, 71-80. Ecoscience 2007., 14, 71-80
  9. Foss, P. J., O’Connell, C. A. and Crushell, P. H Bogs and Fens of Ireland – Conservation Plan 2005, Irish Peatland Conservation Council, Dublin; 2001.
  10. 68.5% of emissions . EPA, 2008. Emissions Trading—Final Allocation Decision; Tuohy et al., 2009
  11. Ibid 10
  12. Douglas, C., Fernandez, F., and Ryan, J. In Peatland habitat conservation in Ireland, International Peat Congress, 2008
  13. Schouten, M.G.C. 2008. Peatland research and peatland conservation in Ireland: review and prospects. In: Feehan, J. (Ed.), 13th International Peat Congress. International Peat Society, Tullamore, Ireland
  14. Ibid 10
  15. According to Galway East Fine Gael TD Paul Connaughton “Turf ban will hurt Galway families”-Galway Independent March 2008.
  16. Wuebbles and Hayhoe (2002) surmise that reaction with hydroxyl radicals account for about 90% of the removal of methane, while transport to the stratosphere (~5%) and dry soil oxidation (~5%) account for almost all the rest.
  17. Ibid 16
  18. IPCC, 2007. Fourth Assessment Report: Climate Change. Intergovernmental Panel on Climate Change
  19. Ibid 18
  20. A video of a lecture by Allan Savory in which he explains his work can be found at
    http://www.feasta.org/2009/11/07/2009-feasta-lecture-keeping-cattle-cause-or-cure-for-climate-crisis/
  21. Ibid 14
  22. O’Mara,F.,P., M. Ryan, J. Connolly, P. O’Toole, O. Carton, J.J. Lenehan, D. Lovett, B. Hyde, E. Jordan and M. Hawkins Climate Change – Estimation of Emissions of Greenhouse Gases from Agriculture and Strategies for their Reduction: Environmental RTDI Programme 2000-2006, Wexford: EPA. 2007.
  23. EPA, Ireland’s Greenhouse Gas Emission Projections 2008-2020 [online], available:
    http://epa.ie/downloads/pubs/air/ airemissions/ghg_Emission_Proj_08_12_30032009.pdf [accessed 30 Jun 2009]. 2009.
  24. EPA, National Inventory Report, 2009 [online], available: http://coe.epa.ie/ghg/nirs/NIR_2009_IEv1.2.pdf [accessed 30 Jun2009]. 2009.
  25. Ibid 22
  26. Ravishankara, A.R., Daniel, J.S., and Portmann, R.W., Nitrous Oxide (N2O): The Dominant Ozone-Depleting Substance Emitted in the 21st Century Science 2009. 326(5949): p. 123-125.
  27. Warneck, P., Chemistry of the natural atmosphere. 1988, San Diego: California: Academic Press.
  28. Goldberg, S.D. and Gebauer, G. 2009. Drought turns a Central European Norway spruce forest soil from an N2O source to a transient N2O sink. Global Change Biology 15: 850-860.
  29. Coulter, B.S., Murphy, W. E., Culleton, N., Quinlan, G. and Connolly, L., A survey of Fertilizer Use from 2001-2003 For Grassland and Arable Crops. 2005.
  30. Coulter, B.S., & Lalor, S., Major and Micro Nutrient Advice for Productive Agricultural Crops. 2008.
  31. Kennedy, E., French, P., O’Brien, B., Low fixed cost expansion options with increased labour efficiency. TResearch, 2009. 4(2): p. 44-45.
  32. O’Driscoll, K., Boyle, L., French, P., Hanlon, A., The Effect of Out-Wintering Pad Design on Hoof Health and Locomotion Score of Dairy Cows. J. Dairy Sci., 2008. 91(2): p. 544-553.
  33. De Klein, C.A.M., Sherlock, R.R., Cameron, K.C., van der Weerden, T.J., Nitrous oxide emissions from agricultural soils in New Zealand– a review of current knowledge and directions for future research. Jour. of the Royal Soc. of New Zealand, 2001. 31(3): p. 543-574.
  34. Ryan, D., A Slurry Spreader to Meet Farming Needs and Environmental Concerns 2005, Teagasc.
  35. Bertram, C., Allusion, F., Avatar, L., van Groningen, J.W., Veto, G., Grinning, C., Pig slurry treatment modifies slurry composition, N2O, and CO2 emissions after soil incorporation. Soil Biology and Biochemistry, 2008. 40(8): p. 1999-2006.
  36. Letter to the UK Parliament, 23 October, 2009. Download pdf file

Featured image: Peat bog. Author: Colin Broug. Source: http://www.sxc.hu/browse.phtml?f=view&id=1348032

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