Last week's announcement by Tim Flannery that by 2005 we may have already hit the greenhouse-gas red zone of 455 parts per million (ppm), if correct, puts the world, and, in particular, our efforts to combat climate change, under a glaring new spotlight.

What's so special about 455ppm? It is the concentration of greenhouse gases in the atmosphere that many scientists agree would bring a higher than 50% likelihood of an increase in global average temperatures of more than 2 degrees centigrade above pre-industrial levels. 455ppm is the red zone in greenhouse gas levels because 2 degrees of temperature rise is regarded as the red zone for actual climate change effects on our planet. This is a level that could cause the world to endure potentially catastrophic runaway climate change feedback loops (an exponential increase in ice-melt, drying and dying forests, permafrost melt, and more, that would, in turn, dramatically increase the level of greenhouse gases in the atmosphere... and so on...).

Should we be surprised at this revelation? Concerned, yes, surprised, no not really.

Titanic Blunders by Throbgoblins

Back in June James Hansen, the level-headed and normally quiet-spoken Head for NASA’s Goddard Space Flight Centre, criticised his scientific peers by stating the Intergovernmental Panel on Climate Change (IPCC) had seriously underestimated where we stood in the grand global warming scheme of things, criticising their 'linear' reporting of arctic ice-melt - which ignored an inevitable icemelt tipping point, where decreased ice-cover translates to less reflected light and more warmth absorbed by growing ocean cover, amongst other things. Back in April we noted the political (and hence industrial) pressures on the IPCC scientists to be 'politically correct'. And, back in May, Guardian investigative reporter George Monbiot came out with an almost identical figure to Tim Flannery:

You begin to understand the scale of the challenge when you discover that the current level of greenhouse gases in the atmosphere (using the IPCC’s formula) is 459ppm. We have already exceeded the safe level. - Giving Up on Two Degrees

George Monbiot had, at the time, dared to state his belief that by 2050 we need to have cut our emissions by 90% - considerably more than the 50% figure being considered by various political bodies, like the European Union, and in stark contrast to the United Nation's Kyoto framework with its current formal goal of a 5% emissions reduction below 1990 levels by 2012 (goals for beyond 2012 have yet to be determined...).

On top of this, now a team of scientists in Canada, a team whose computer models are the basis for some of the IPCC reports, state that their most recent studies call for a 100% reduction in greenhouse gases below 2006 levels (the previous reductions quoted were for below 1990 levels). Just in case this didn't sink in, they're saying that to avert dangerous runaway climate change effects we need to reduce our emissions to zero by 2050.

Weaver's team used a computer model to determine how much emissions must be limited in order to avoid exceeding a 2°C increase. The model is an established tool for analysing future climate change and was used in studies cited in the IPCC's reports on climate change.

They modelled the reduction of industrial emissions below 2006 levels by between 20% and 100% by 2050. Only when emissions were entirely eliminated did the temperature increase remain below 2°C.

A 100% reduction of emissions saw temperature change stabilise at 1.5°C above the pre-industrial figure. With a 90% reduction by 2050, Weaver's model predicted that temperature change will eventually exceed 2°C compared to pre-industrial temperatures but then plateau. - New Scientist

So, where do we stand today? Are we heading to hell in a hand basket?

In some ways, it could be perceived as self-defeating to even publish the details above. The risk that some may cement themselves into an "eat, drink, and be merry, because tomorrow we die" mentality is very real. But, of course, real answers and solutions will never arise through concealing information.

If it's any consolation, Gavin Schmidt from Real Climate - an independent climate science website that's respected for giving impartial responses to both global warming 'alarmists' and 'skeptics' - disagrees with Tim Flannery's statements, believing he is misreading draft data, and that pulling up short of 450ppm is still possible:

The important number is CO2_e (Total) which is around 375 ppmv. Stabilisation scenarios of 450 ppmv or 550 ppmv are therefore still within reach. - Real Climate

This has caused a bit of a stir in in climate-cyberspace, and we have yet to sight a reaction or clarification from Tim. Gavin, wisely, still recognises the need to qualify his stand however:

Claims that we have passed the first target are simply incorrect, however, that is not to say they are easily achievable. - Real Climate

The IPCC's 'AR4 Synthesis Report' will be out soon enough (November 7th), so we may get an official response to Tim Flannery's statements in due course. It should be noted, though, that this latest IPCC report is simply a policy-relevant summary of the previous three reports released for 2007 - all of which were, themselves, regarded as conservative and even 'behind the times', due to the time involved in the intense peer-review process that filters incoming data flows. In other words, it will still be missing the most recent findings from this year - a year where arctic ice shrinkage has broken all records, and governments are tensing up for competition over a frontier that was inaccessible previously.

This impending IPCC report is specifically aimed at giving governments the 'best scientific guess' upon which to base policy decisions - it will be a critical ingredient for December's United Nations Framework Convention on Climate Change (UNFCCC) in Bali, Indonesia (Dec 3-14), where a post-2012 Kyoto framework should begin to get hammered out.

One aspect that isn't mentioned in the articles above is the role of global dimming in all this. Global warming wields a double-edged sword - our greenhouse gas emissions are warming the world, but our other airborne pollutants - aerosols like ash, soot, sulfur, etc. - are working in the other direction, keeping the strongest effects of global warming off our backs, as it were. Global dimming is an acknowledged phenomenon - including by Real Climate scientists (although they are quick to admit that the effects are difficult to quantify). As we've written before, global dimming may well be Veiling Our True Predicament, yet it is unclear to what degree the impacts of simultaneously reducing greenhouse gas emissions as well as the associated aerosols have been incorporated into the latest climate models. If we ever find the political will to reduce our greenhouse gas emissions and the personal determination to reduce our lifestyles of excess, the skies will begin to clear of visable pollutants as well. And so, just like the days after 9/11, when U.S. temperatures reportedly rose as a result of the nation-wide grounding of aircraft, we can expect a difficult-to-predict convergence of cooling and warming effects.

In other words, if we still have the brief ten-year window James Hansen threatened us with only a few months ago - we need to make the best use of it.

Despite technical contentions (with climate science and the infinite possible interactions of natural systems within our biosphere, such contentions will always exist), the general view is that global warming is advancing faster than most scientists anticipated. This is not a time for despair, however - but a time for thoughtful concerted action. The world is changing, we need to seek to both reduce that change, and yet simultaneously prepare for it. As any sensible doctor will advise a patient suffering from lifestyle related health issues - while it's best to cease your destructive habits at an early age, it's never too late to do what you can to fend off the worst damage. There is no time like the present.

There is a very real human tendency, I feel, to get bogged down in minutiae. The reality is we know what's causing global warming, and we know that the sooner we act the better it will be for us all.

I'll leave you with a quote I appreciated from Dr. Glen Barry's response to Tim Flannery's announcement:

Humanity is in for a nasty ride as the ecological fabric of being is deeply frayed. Yet the Earth and her humanity possess amazing regenerative and adaptive capabilities. We must trust in our ability to define and implement sufficient policies to pull back from the brink of destruction; starting with rigorous policies to reduce human population, end use of coal and other fossil fuels, preserve and restore ancient terrestrial ecosystems, and return to the land for a life of rich voluntary simplicity. - Climate Ark