 regarded as a considerable step forward.
But the sum of all the commitments is simply inadequate for the point where emissions peak as a whole and then start to decline to come early enough, Professor Anderson says.
The date of the emissions peak is increasingly seen as a vital point in checking the progress of the warming.
Last year, the Met Office's Hadley Centre for climate prediction and research said that if global emissions peaked in 2015 or 2016 and then declined annually at a rate of four per cent, there would be a 50-50 chance – but no more than that – of keeping the rise in temperatures to two degrees, the goal upon which much of the world's climate policy is premised.
For every ten years that the peak was delayed, the Hadley Centre said, the world would be committed to another 0.5 of a degree of warming.
Professor Anderson points out that there is a widespread assumption that an emissions peak might come relatively early, but asserts that the political and economic will to bring this about is actually absent.
He writes: "For example, the [Lord] Stern and the [UK] Committee on Climate Change reports are premised on global emissions reaching their highest levels by 2015 and 2016 respectively, before beginning a process of year-on-year reductions."
He goes on: "However, amongst those working on climate change there is near universal acknowledgment that such early peaking years are politically unacceptable – yet the Stern and the CCC analyses remain pivotal in the formation of emission-reduction policy.
"The statements by the US, China and India, allied with commitments from other nations, suggest peaking global emissions between 2020 and 2030 is about as hard as the economic and political orthodoxy is prepared to push in terms of emission reductions.
"If peaking global emissions between 2020 and 2030 is left unquestioned, the cumulative quantity of greenhouse gases emitted will be sufficient to put temperatures on a 4 degrees C or higher trajectory."
In recent years, emissions have shot up in a way no-one expected even a decade ago, largely owing to the breakneck industrialisation of China, which doubled its CO2 output over the decade from 3bn to 6 bn tonnes, and in doing so overtook the US as the world's biggest polluter. Currently global carbon emissions are rising by nearly three per cent annually, making a four per cent annual decline a tall order indeed, and one that the present Copenhagen commitments would not remotely be able to facilitate.
There has to be a move to a radical new level of emissions cuts, Professor Anderson says, if dangerous climate change is to be avoided.
He writes: "If Copenhagen is to have any chance of kick-starting a global movement to stay below the 2 degrees C characterisation of dangerous climate change, it must inspire and instigate a rapid shift away from the current political and economic consensus."
The first challenge, he says, is to get political buy-in to what the science is saying in relation to, at least, a 50:50 chance of not exceeding 2 degrees C.
"In brief, wealthy (OECD) nations need to peak emissions by around 2012, achieve at least a 60 per cent reduction in emissions from energy by 2020, and fully decarbonise their energy systems by 2030 at the latest.
"Alongside this, the 'industrialising' nations (non-OECD) need to peak their collective emissions by around 2025 and fully decarbonise their energy systems by 2050."
He notes: "This scale of reductions is presently far removed from that which the negotiators in Copenhagen are intending to consider."
He concludes: "The second challenge for Copenhagen, therefore, is to make a clear and explicit decision to do all that is necessary to put global emissions on a 2 degrees C pathway, even if this requires a temporary cessation in economic growth amongst the wealthy OECD nations."