The issue of CCS has been on the table since the COP-10 meeting in 2005 but decisions were always postponed.
This time, instead of the question being framed in a 'yes' or 'no' format, two options that both enable funding for the experimental technology have been approved by the Kyoto Protocol's scientific advisory board, the Subsidiary Body for Scientific and Technological Advice (SBSTA).
Under the first option, CCS would be funded if concerns about carbon leakage from underground geological formations, environmental risk, legal liabilities and monitoring are "addressed". This would take place in discussions at the next SBSTA meeting with input from parties, observers and technical experts.
Under the second option, CCS would be deemed ineligible for funding until and unless such issues are "resolved in a satisfactory manner" by Kyoto Protocol signatories. In practice, observers expect robust pressure would ensure that such resolutions were achieved, albeit with potentially greater safeguards and conditions attached.
Final approval of the CCS proposals today (10 December) will depend on the shape of a broader deal that is currently being thrashed out at the summit.
CCS is 'one bit of the mosaic'
Artur Runge-Metzger, the EU’s chief climate negotiator, told EurActiv from Cancún that CCS was being hotly debated. "We are at the stage of looking at the entire package and this is one bit of the mosaic," he said.
"The EU legislation is there to allow for CCS. We think it is an important element and in Europe we are going into the stage of testing large scale whether this is the technology that can deliver."
Negotiators have already moved the issue up the agenda. An original draft recommendation from SBSTA, obtained by EurActiv, had contained an option declaring CCS technology ineligible for credits in the world's carbon market.
But EurActiv understands that following pressure from OPEC states, particularly Saudi Arabia, the AOSIS group of South American countries which had led opposition to CCS backed down, as a negotiating tactic to protect their "red lines".
The economic viability of CCS has been repeatedly questioned, unless great subsidies are pumped in.
One recent report commissioned by EU Energy Commissioner Günther Oettinger, "EU Energy Trends to 2030", suggested that the carbon price in Europe between now and 2030 was likely to remain too low for the current CCS subsidies offered by European governments to make the technology viable.
And a 2009 study by Landesbank Baden-Württemberg similarly concluded that CCS was "not practicable on commercial and economic grounds".
But the technology's potential to reduce emissions is not in doubt.
The Intergovernmental Panel on Climate Change's report into CCS found that it could reduce carbon dioxide emissions from power plants by up to 80-90%. By 2050, some 20-40% of all global fossil fuel emissions could technically be suitable for capture, it said.
But CCS remains stubbornly unpopular with environmentalists who warn that this time frame would be too late to stop runaway global warming, and renewable energy is anyway a much wiser investment.
They charge that energy firms like BP and Shell International support CCS because one of its byproducts – liquefied carbon – could theoretically be pumped into depleted oil fields to allow the easy extraction of remaining reserves.
In July 2008, Shell International's then-climate adviser, David Hone, was one of the first business voices to propose bringing CCS into the CDM. On 8 December, he was appointed the new Chair of the Board of the International Emissions Trading Association, which works in partnership with the World Bank to develop a global greenhouse gas market.
Opposition to CCS still rife
Opposition to CCS from countries such as Brazil led to an option rendering it ineligible for CDM funding being inserted into a draft Kyoto Protocol text for 2012.
However, Bas Eickhout, a Dutch Green MEP currently in Cancún, doubted that it would have much effect. "Given the way that these discussions have been done, it's clear that people will go along with [CCS] as a compromise in order to keep Saudi Arabia from blocking any other texts," he said.
He predicted that delegates would finally support the SBSTA option two.