We have learnt to expect surprises at UN climate change summits.
At Durban, a year ago, there was the unexpected, but welcome, agreement to begin negotiations on a new legally binding instrument, involving all major emitters of greenhouse gases, to be finalised by 2015 and to take effect in 2020.
At Copenhagen and Cancun, in 2009 and 2010 respectively, negotiators, to the surprise of many, abandoned "Plan A" for an international emission-control agreement in favour of "Plan B" (as proposed by the Danish prime minister) including 2020 "pledges" and an information-exchange agreement among countries about emissions.
The unanticipated may also be in store this year: Qatar, as host, may be seeking a big initiative to underline its credentials globally.
The summit, which began yesterday, represents an unparalleled opportunity to engage the GCC states. With their fossil-fuel wealth and growing technological and research strengths, GCC countries could transform the global climate-change strategy. Yet, as a group, they have been largely ignored.
So what might the GCC's "game-changing" contribution look like?
GCC countries could lead development and funding of carbon capture and storage (CCS), the technology to sequester greenhouse gases from burning fossil fuels, preventing emission into the atmosphere.
There is no credible scenario, without CCS, under which emissions can be sufficiently reduced to limit the global average temperature rise to 3°C by 2100, well above the agreed UN goal of 2°C.
Storage of carbon dioxide in rock from which oil and water have been extracted is well established. Plans are being discussed in many countries, but only a few, including China and Norway, have experience of industrial-scale pilot projects for extracting carbon dioxide from power-plant exhaust gases.
Estimates say the overall costs of CCS are comparable to the extra costs of renewable energy. And CCS has the advantage of not depending on weather, and is particularly applicable in countries that rely on coal, such as China and India.
In the long term, CCS will be viable only if sufficient costs are imposed on installations that emit carbon.
Estimates suggest that, once CCS technology is mature, a carbon price of between $44 and $103 (Dh162 and Dh 378) per tonne would make CCS viable. The current price in the European Union (the world's top carbon market) is much lower.
However, a tightening of the cap on emissions from 2013 means that the EU carbon price is on a trajectory towards the critical price band. Moreover, recent steps to create carbon markets in Australia, China, Mexico, South Korea and California indicate a global trend.
Achieving CCS in the short-to-medium-term requires big capital investments. With uncertainty about regulation and the future price of carbon, plus widespread fiscal constraints, those investments have not yet been forthcoming.
This could soon change. First, the regulatory outlook is more certain now. The Kyoto Protocol has been extended and stricter carbon constraints on all major countries are probable after 2020, reducing the regulatory risk of investment in CCS.
Second, GCC states have a growing incentive to commercialise CCS, possibly by using their massive sovereign wealth funds. Because CCS eliminates greenhouse gas emissions, it can make fossil fuel markets environmentally sustainable. Once commercialised, CCS technology will be exportable, creating new jobs.
Third, China is planning a timetable for emissions reductions under a post-2020 climate-change deal. It is in fossil-fuel-dependent China's interest to commercialise CCS and other advanced technologies. As rapid economic growth leads to construction of many new power stations, mostly coal-fired, large demand for CCS should lower costs.
As well as China and the GCC states, the EU, as the world's largest carbon market, would also support progress on CCS. Driving down CSS costs would help countries such as Poland and the Czech Republic, that rely on coal and so now act as a brake on Europe's ambition to limit climate change.
The opportunity is crystal clear. If Qatar is looking for something big to showcase its credentials on the world stage, this may be it.
Lord Hunt is visiting professor at Delft University, and former director-general of the UK Met office