Green House Gas Emissions and Global Warming

Green House Gas Emissions and Global Warming:

The global effect from Human activities, including the burning of fossil fuels, increased farming, and deforestation, is leading to an increase in the three main greenhouse gases that are present within the Earths atmosphere. These are Carbon Dioxide (CO2), Methane (CH4), and Nitrous Oxide (N2O). Greenhouse gases posses the insulating property of being able to reflect long wave radiation. Thus they act to hold heat within the atmosphere by reflecting back long wave heat radiation, which itself radiates from the Earth after it is warmed by solar radiation. Inevitably as the insulation of this long wave heat radiation increases, then so to does the temperature of the Earth’s atmosphere and Oceans.

The main greenhouse gas by volume is CO2, and this has been increasing as a constituent within the Earth’s atmosphere from about 270 parts per million around the year 1800 to about 400 parts per million today. A main cause of CO2 emission is from the burning of fossil fuel, which served to sequester CO2 from the atmosphere in past times. The volume of CO2 removed from the Earth’s atmosphere, by the formation of fossil fuels and carbonate rocks, is indicated by past atmospheric CO2 levels. Before land based plants removed large quantities of CO2 from the atmosphere, during the Carboniferous period, the previous geological period; the Devonian, possessed atmospheric CO2 levels of approximately 2200 parts per million. This is 8 times the preindustrial atmospheric CO2 level. Although there were higher levels off atmospheric carbon dioxide in ancient geological times, the current rate of return of the sequestered CO2 is happening too quickly to allow life and climate systems to adjust.

Not all CO2 emissions stay in the atmosphere. The ocean, and to some extent the land, act as large carbon sinks which significantly slow the accumulation of atmospheric CO2, and the resulting climate change. Indeed the Oceans contain about 50 times the amount of CO2 to that held within the atmosphere. However global warming will inevitably cause seawater temperatures to rise. Warmer water holds less dissolved gas than colder water, so the ocean will not be able to store as much CO2. Consequently the effect will be to cause even higher atmospheric CO2 concentrations and a further acceleration of global warming. This combined with an increase in the release of CO2 from the soil, as temperatures rise, could lead to a runaway greenhouse effect. (Oceanus 2006). A further problem may be presented by the presence of large volumes of gas hydrate deposits beneath the seabed. Hydrates are a frozen mixture of water and gas, primarily methane. These contain reserves equal to 3000 times the amount of Methane already present within the atmosphere. If shallow hydrates are destabilised in a warming world, it could have a positive feedback effect and drive temperatures to even higher levels. (BBC 2006).

In Ireland the emissions of CO2 accounted for 67.6% of total greenhouse gas emissions in 2006. The 2006 contributions of CH4 and N2O were 18.9 per cent and 12.4 per cent respectively. Combustion sources in the energy, transport, industrial, commercial, and residential sectors, accounted for most CO2 emissions. The CH4 emissions were produced mainly in the agriculture and waste sectors, and most of the N2O emissions were generated in agriculture. (EPA 2008). These greenhouse gases do not reflect long wave radiation equally, for instance Methane is 25 times more insulating than Carbon Dioxide making it a far more potent greenhouse gas.

In Ireland there has been some notable success in curtailing emissions with reductions in the agricultural and waste sectors. The use of landfill gas for energy reclamation, in combination with agriculture emissions decreasing by almost 12 per cent from their peak in 1998, has served to stabilise emissions overall. The problem in Ireland is the transport sector, which is where the largest increases in CO2 emissions have taken place. These CO2 emissions from transport, which are largely accounted for by road traffic in Ireland, increased by 170% between 1990 and 2006. (EPA 2008). A major contributing factor to this increase is caused by the lack of transport infrastructure, and defective planning. In Ireland there is currently an 18% over supply of rural housing. Some 560 000, or 22.5%, of houses built are one-off rural houses. In combination with a lack of significant rural public transport this scattergun approach to planning makes increased road traffic unavoidable.

In fairness this is not just a problem in Ireland, globally 28.9% of CO2 emissions were accounted for from transport in 2001. (Banister, 2005, p16).

Indeed the climate change caused by global warming presents a World wide risk, with the impacts acting on a global and national level. Globally the impacts of climate change threaten basic components of life, such as:

Access to Water.
Food Production.
Land Use.

Furthermore the EU considers that a global temperature increase of more than 2C entails an unacceptable risk of a tipping point for dangerous and irreversible impacts of climate change being exceeded. The distinct risks and challenges that climate change poses to Ireland are:

More intense storms and rainfall events.
An increased likelihood of flooding in rivers and on the coast, where almost all our cities and large towns are situated.
Water shortages in summer in the east and the need for irrigation of crops.
Changes in the distribution of species.
The possible extinction of vulnerable species.

(Source: EPA, 2008)

The Kyoto protocol was the landmark international agreement to reduce the emissions of 6 greenhouse gases by 5.2% below 1990 levels. The agreement had a difficult birth, due the Worlds largest emitter of greenhouse gases, the USA, abstaining. However by February 2005 enough countries had become signatories for the protocol to come into effect. The protocol allowed unequal contributions to the reduction in greenhouse gas emissions across countries. (Banister 2005).

Ireland secured a particularly good target in actually being allowed to increase its emissions by 13 % above its 1990 levels, so as to allow for a degree of further development. Despite this leeway Ireland has failed to stay within its agreed Kyoto greenhouse gas emissions, of 62.8 mega tonnes of CO2 equivalent greenhouse gas emissions between 2008 and 2012, and in 2006 it emitted 69.8 mega tonnes of CO2 equivalent greenhouse gas emissions. Ireland’s average CO2 production rate per person is the second worst in the EU, after Luxemburg at 17 tonnes of CO2 equivalent. This compares to the global average of 3.9 tonnes of CO2 equivalent, and the rate of 2 tonnes of CO2 equivalent that is required to stabilise atmospheric emissions with a World population of 6 billion. (Banister 2005).

A major cause of greenhouse gas emission is from the use of energy, derived from finite fossil fuel. Humans are living upon the World’s energy principle (fossil fuel) and not its energy income (renewable energy). A major requirement of sustainable development is to conserve and use energy more efficiently. Renewable energy is a harder win than using fossil fuel, and even if the current huge usage of fossil fuel energy could be replaced by renewable energy it would require a massive financial investment, with a major impact on the environment, in order to accommodate such infrastructure. Clearly the rate of energy usage required in sustaining such an inefficient and dispersed economic model as Ireland’s is itself unsustainable.

In March 2007 the European Council set emission reduction targets of 20-30% across the EU by 2020, as part of the EU sustainable development strategy. These are precise and legally binding targets that were provoked by the Stern Review of 2006, which forecasts that the costs of inactivity on CO2 emissions could be between 5-20% of global domestic product. (HM Treasury 2006). The key targets set by the European Council for the year 2020 are as follows:

A 20% reduction in greenhouse gas emissions (averaged across all member states), rising to 30% if an international agreement on emissions reduction is reached.
The EU share of renewable energy is to increase to 20% of total energy consumption, from the current EU average of 8.5%.
Increased energy efficiency is to reduce energy consumption by 20%. This will save approximately 100 billion, and reduce emissions by 800 million tonnes per year.
(Source: EU Commission, 2008)

A major driver for achieving these targets will be the “European Union Emissions Trading System” (ETS). This will provide a market based solution to incentivise cuts in CO2 emissions, following the polluter pays principle. Currently companies generating more than 10 thousand tonnes of CO2 a year are allocated allowances to emit CO2 by national governments. These allowances can be traded, incentivising companies to invest in reducing emissions. This system covers some 10 000 industrial plants across the EU, including power plants, oil refineries, and steel mills, and accounts for almost half of the EU’s CO2 emissions. These allocated allowances are to be replaced by the auctioning of allowances, and their gradual reduction on the ETS market. The proceeds of the ETS trading will be invested in low Carbon research and development.


The EU is leading the way internationally, in tackling the causes of climate change. However the task of bridging the gap between aspirations and the actual achievement of emission reductions is huge. For Ireland, struggling to meet its relatively modest Kyoto emission targets, the compliance with the EU Sustainable Development Strategy will require a fundamental restructuring of its socio economic model. This will require not only improved efficiencies in energy production, but also reduction in consumption, facilitated by more energy efficient modes of transport, and the planning necessary to implement and make effective such transport.


Amos, J. (2006) Methane ices pose climate puzzle. In BBC Science and Environment, ed. BBC News. London: BBC.

[Accessed 27th October 2008] Available from World Wide Web:


Banister, D. (2005) Unsustainable transport : city transport in the new century. London ; New York: Routledge.

Commission of the European Communities. (2008) 20 20 by 2020 Europe’s climate change opportunity. Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions. Brussels:

[Accessed 3rd December 2008]. Available from World Wide Web:


Environmental Protection Agency. (2008) 2008 – State of the Environment Report. Dublin: [Accessed 16th October 2008]. Available from World Wide Web:


HM Treasury. (2006) Stern Review. In Commission of the European Communities. (2008) 20 20 by 2020 Europe’s climate change opportunity. Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions. Brussels:

[Accessed 3rd December 2008]. Available from World Wide Web:


Kettlewell, J. (2004) Methane ‘belch’ theory gets boost. In BBC Science and Environment, ed. BBC News. London: BBC.

[Accessed 27th October 2008] Available from World Wide Web:


Oceanus. (2006) How Long Can the Ocean Slow Global Warming? Woods Hole, MA 02543: Woods Hole Oceanographic Institution. [Accessed 3rd January 2009]. Available from World Wide Web: