Mark Lynas, author of the 2007 book Six Degrees, argues that to get world governments to take the climate issue seriously, a disaster might be needed sometime in 2010 or 2011.
At a session in Stockholm, Lynas and other climate experts tried to envisage some scenarios: "Agree and ignore," where governments admit there is a problem but do nothing, and "Kyoto Plus," which would be committing to new, stronger targets but not really getting emissions to stop rising before 2030.
And then there's "step change."
Here we envisaged massive climate disasters around the world in 2010 and 2011 causing a sudden increase in the sense of urgency surrounding global warming. Energised, world leaders ditch Kyoto, abandoning efforts to regulate emissions at a national level. Instead, they focus on the companies that produce fossil fuels in the first place - from oil and gas wells and coal mines - with the UN setting a global "upstream" production cap and auctioning tradable permits to carbon producers. Instead of all the complexity of regulating squabbling nations and billions of people, the price mechanism does the work: companies simply pass on their increased costs to consumers, and demand for carbon-intensive products begins to fall. The auctioning of permits raises trillions of dollars to be spent smoothing the transition to a low-carbon economy and offsetting the impact of price rises on the poor. A clear long-term framework puts a price on carbon, giving business a strong incentive to shift investment into renewable energy and low-carbon manufacturing. Most importantly, a strong carbon cap means that global emissions peak as early as 2017.
This "upstream cap" approach is not a new idea, and our approach draws in particular on a forthcoming book by the environmental writer Oliver Tickell. However, conventional wisdom from governments and environmental groups alike insists that "Kyoto is the only game in town", and that proposing any alternative is dangerous heresy.
But let's look at the modelled temperature increases associated with each scenario. "Agree and ignore" sees temperatures rise by 4.85C by 2100 (with a 90% probability); for "Kyoto plus", it's 3.31C; and "step change" 2.89C. This is the depressing bit: no politically plausible scenario we could envisage will now keep the world below the danger threshold of two degrees, the official target of both the EU and UK. This means that all scenarios see the total disappearance of Arctic sea ice; spreading deserts and water stress in the sub-tropics; extreme weather and floods; and melting glaciers in the Andes and Himalayas. Hence the need to focus far more on adaptation: these are impacts that humanity is going to have to deal with whatever now happens at the policy level.
But the other great lesson is that sticking with current policy is actually a very risky option, rather than a safe bet.