RESPONDING TO GLOBAL WARMING
It is now clear that global warming is significantly changing our climate and will have serious and perhaps unforeseen consequences. For example, in 2006, an inhabited island in the Bay of Bengal was submerged by rising sea levels, displacing its entire population – and reliable observers predict that increasingly more island and coastal lands will be lost. This reflects rising atmospheric CO2 levels and the associated heightened global temperatures of the last 250 years, driven by our escalating consumption of fossil fuels. CO2 levels reached 382 parts per million (ppm) in 2006, compared with about 280 ppm in 1750, and the “tipping point” of irreversible global warming is foreseen within the coming decade.
Planet Earth, over hundreds of millions of years, has regulated its climate through sedimentation patterns involving carbonate (for example, limestone) and carbonaceous (for example, coal) deposits. Life has tended to flourish when the increased formation of such sediments led to a reduction in atmospheric CO2. The geological record preserves evidence of many cycles of waxing and waning CO2 levels. Although we may take comfort from the fact that irreversible change never set in, even when CO2 concentrations rose to five times current levels, the same geological record indicates that cycle oscillations could be quite rapid, with potentially dire consequences for humans, and other species.
The Kyoto Protocol represents the international response to the current challenge. In the case of Ireland the recently published climate change strategy2 comprehends a series of remediation measures, which include carbon sequestration. The sequestration, or storage, of CO2 deep underground is an option, which has yet to be assessed in Ireland. Full scale applications have yet to be implemented anywhere, although pilot schemes are in operation in several countries, but recent research has focused on capturing CO2 emissions from fixed point sources (for example, power stations and certain industrial complexes) and storing them in deep geological formations such as depleted oil and gas fields, coal deposits, saline aquifers and mafic/ultramafic rocks.
A schematic diagram illustrating geological storage options for CO2. Diagram copyright of, and reproduced by permission of, Cooperative Research Centre for Greenhouse Gas Technologies, Australia.
GSI, in partnership with the Environmental Protection Agency (EPA), Sustainable Energy Ireland, Petroleum Affairs Division (D/CMNR) and the Geological Survey of Northern Ireland, recently formulated a specification for a preliminary assessment during 2007 of the underground sequestration potential of the island of Ireland, both onshore and offshore. In parallel, under the Government’s Strategy for Science, Technology and Innovation (SSTI) initiative, the EPA and GSI propose to assess the storage potential of deep saline aquifers in the vicinity of Moneypoint Power Station, which currently emits about 10% of Ireland’s CO2 emissions to atmosphere.
1 Reference: Cooperative Research Centre for Greenhouse Gas
2 Reference: Monaghan, R., Bazilian, M. and Brennan, G. 2006.
Carbon Dioxide Capture and Storage in Ireland: costs, benefits and future potential, Sustainable Energy Ireland, 30pp.