A major challenge for the world is climate change or global warming.
What is Global Warming?
Gases in the atmosphere affect the earth’s temperature by trapping radiation from the sun - this is known as the greenhouse effect. Without this greenhouse effect the world would be too cold for life to exist.
Greenhouse gases (GHGs) include carbon dioxide (CO2), methane (CH4), nitrous oxide (N20) and water vapour (H20), amongst others, and occur naturally. However, human activities, such as the combustion of fossil fuels, produce additional GHGs which build up in the atmosphere causing an enhanced greenhouse effect. This results in more heat being trapped, termed ‘global warming’. The Intergovernmental Panel on Climate Change (IPCC) has emphasised that there is enough evidence to show that the world is warming and that action needs to be taken.
CO2 makes up almost 80% of anthropogenic (human-induced) GHG emissions. Over the last century, the amount of CO2 in the atmosphere has risen, in large part driven by fossil fuel use but also because of other factors such as land-use change and deforestation. Coal use is one of many human activities that generate GHG emissions (see graph).
Global Greenhouse Gas Emissions - Sources & Activities
Source: UNFCCC & WRI
Coal & Climate Change
The coal industry is committed to minimising its GHG emissions and action is being taken in a number of areas. Improving coal combustion efficiency is an important step. Research from the International Energy Agency (IEA) has found that replacing older coal-fired power stations with larger more efficient plants could reduce global GHG emissions by 5.5%. To put this 5.5% global GHG emission reduction figure into context, the intended effect of all the measures included in the Kyoto Protocol on Climate Change is 5%.
Carbon capture and storage (CCS) offers the opportunity to further reduce CO2 emissions to the atmosphere from coal-fired power stations. Capturing the CO2 emitted by the use of coal and other fossil fuels and injecting it for storage in deep geological formations is the only currently available technological solution that will enable deep cuts in greenhouse gas emissions whilst maintaining the energy infrastructure needed for growth.
Another important area where the coal industry is working to reduce GHG emissions is through the recovery of methane released during coal mining. The global warming potential (GWP) of methane is 23 times greater than that of CO2, which means that for a given volume of methane emitted, the resulting global warming effect will be 23 times stronger over one hundred years compared to the same volume of CO2. Methane remains in the atmosphere for a period of approximately 12 years after it has been emitted. In comparison, CO2 is estimated to have an atmospheric lifetime of tens of 50-200 years.
Coal mining is an important anthropogenic source of methane emissions. Although agriculture accounts for by far the largest proportion of methane emissions from human activities, emissions from all coal mining related activities - extraction, transport and storage - accounted for 7.4% of total global anthropogenic methane emissions in 2005.
International Agreements to Tackle Climate Change
The United Nations Framework Convention on Climate Change (UNFCCC) entered into force in 1994 and sets an overall framework for intergovernmental efforts to tackle climate change. The ultimate objective of the UNFCCC is the: “stabilisation of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a timeframe sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner”.
Negotiated under the UNFCCC, the Kyoto Protocol was agreed in Kyoto, Japan, in December 1997. The Protocol established legally binding commitments for reducing greenhouse gas emissions from Annex I countries (industrialised/developed countries) as well as outlining general commitments for all signatories to aim to meet the ultimate goals of the UNFCCC. The Kyoto Protocol entered into force in February 2005 and sets targets for industrialised countries “with a view to reducing their overall emissions of such gases by at least 5% below existing 1990 levels, in the commitment period 2008-2012”.
The Kyoto Protocol introduced three mechanisms designed to give Annex I countries flexibility in how they meet their emissions reduction targets.
(i) Emissions Trading
Allows countries that emit less than their quota of emissions to sell excess credits to those countries that exceed their quota. This paved the way for international emissions credit markets to be established (such as the EU Emissions Trading Scheme). The units traded are known as Assigned Amount Units (AAU) and are each equivalent to one tonne of CO2.
(ii) Clean Development Mechanism (CDM)
The CDM allows Annex I countries to meet a proportion of their emissions reductions commitments by investing in projects designed to reduce GHG emissions in non-Annex I countries. This allows developed countries to offset their emissions and promote sustainable development in developing countries by investing in clean technologies.
(iii) Joint Implementation (JI)
JI allows Annex I countries to trade allowances known as emission reduction units (ERUs) by investing in projects to reduce GHG emissions in other Annex I countries. As with CDM activities, the emissions reductions must be additional to any that would have occurred without the project. A key difference between JI and CDM projects is that JI does not generate new credits; it merely transfers credits from the host country to the investing country.