The Twenty-Seventh Session of the Intergovernmental Panel on Climate Change (IPCC) will take place in Spain from 12-17 November 2007. The IPCC is currently finalizing its Fourth Assessment Report “Climate Change 2007”, also referred to as AR4. The reports by the various Working Groups of IPCC provide the most comprehensive and up-to-date assessments of the current state of knowledge on climate change, including available technologies to deal with climate change.

According to IPCC’s Third Assessment Report, there is new and stronger evidence that most of the global warming observed over the past 50 years is attributable to human activities. These human influences are expected to continue to change atmospheric composition throughout the 21st century.

The greenhouse gas making the largest contribution from human activities is carbon dioxide (CO2). It is released by burning fossil fuels and biomass as a fuel; from the burning, for example, of forests during land clearance; and by certain industrial and resource extraction processes.

Emissions of CO2 due to fossil fuel burning are virtually certain to be the dominant influence on the trends in atmospheric CO2 concentration during the 21st century, and global average temperatures and sea level are projected to rise under all likely scenarios.

The ultimate objective of the UN Framework Convention on Climate Change, which has been accepted by 189 nations, is to achieve stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system, although a specific level has yet to be agreed.

Technological options for reducing net CO2 emissions to the atmosphere include:

• Reducing energy consumption, for example by increasing the efficiency of energy conversion and/or utilization (including enhancing less energy-intensive economic activities);


• Switching to less carbon intensive fuels, for example natural gas instead of coal;


• Increasing the use of renewable energy sources or nuclear energy, each of which emits little or no net CO2;


• Sequestering CO2 by enhancing biological absorption capacity in forests and soils; or


• Capturing and storing CO2 chemically or physically.

Carbon dioxide (CO2) capture and storage (CCS) is a process consisting of the separation of CO2 from industrial and energy-related sources, transport to a storage location and long-term isolation from the atmosphere. CCS has the potential to reduce overall mitigation costs and increase flexibility in achieving greenhouse gas emission reductions.

The widespread application of CCS would depend on technical maturity, costs, overall potential, diffusion and transfer of the technology to developing countries and their capacity to apply the technology, regulatory aspects, environmental issues and public perception.

The Third Assessment Report (TAR) indicates that no single technology option will provide all of the emission reductions needed to achieve stabilization, but a portfolio of mitigation measures will be needed. Most scenarios project that the supply of primary energy will continue to be dominated by fossil fuels until at least the middle of the century.

Most models also indicate that known technological options could achieve a broad range of atmospheric stabilization levels but that implementation would require socio-economic and institutional changes. In this context, the availability of CCS in the portfolio of options could facilitate achieving stabilization goals.

The capture of CO2 can be applied to large point sources where it is then compressed and transported for storage in geological formations, in the ocean, in mineral carbonates, or for use in industrial processes. Large point sources of CO2 include large fossil fuel or biomass energy facilities, major CO2-emitting industries, natural gas production, synthetic fuel plants and fossil fuel-based hydrogen production plants.

Potential technical storage methods are: geological storage (in geological formations, such as oil and gas fields, unminable coal beds and deep saline formations), ocean storage (direct release into the ocean water column or onto the deep seafloor) and industrial fixation of CO2 into inorganic carbonates. The industrial use of CO2 is not expected to contribute much to the overall reduction of CO2.

This Summary Report for Policymakers was approved in detail at the Eighth Session of IPCC Working Group III in Montreal in September 2005, represents the current formally agreed statement of the IPCC concerning current understanding of carbon dioxide capture and storage. It is well written, clear and contains an excellent array of graphics and tables to assist in providing a clear perspective on the technologies that are likely to become commonplace over the next quarter century to deal with CO2 capture and storage.

The Summary for Policy Makers is available here.

The full report is available here.

Source: Inter-governmental Panel on Climate Change.