It’s the kind of near-miss collision which in the past may have led some reporters – too many – down a mistaken path of sensationalizing climate change with inadequate understanding of what lay behind their coverage.

In this case, it started out in the land down under, with well-regarded climate change scientist and author Tim Flannery (a 2007 “Australian of the Year”) reporting that a dangerous greenhouse gas emissions threshold had been exceeded well ahead of forecasts … and with irreversible impacts.

A Reuters Sydney, Australia, piece reported that “one of Australia’s leading scientists” had said an upcoming Intergovernmental Panel on Climate Change (IPCC) report will show atmospheric GHG in mid-2005 at about 455 parts per million of carbon dioxide equivalent. “We thought we’d be at that threshold within about a decade,î Reutersís Michael Perry quoted Flannery, author of the book The Weather Makers as telling Australian television. Flannery, of Macquarie University, was discussing the much awaited IPCC “Synthesis Report,” due to be released in November.

“What the report establishes is that the amount of greenhouse gas in the atmosphere is already above the threshold that could potentially cause dangerous climate change,” Reuters quoted Flannery as saying. At least some U.S. media, including The Washington Post, carried the Reuters piece.

An Associated Press piece published in the International Herald Tribune October 9 fanned the Flannery flames, reporting that “the level of climate-changing gases in the atmosphere has already reached critical levels.” The A.P. story attributed the accelerated emission levels to “strong worldwide economic growth,” in particular in China and India.

Alarm bells soon went off, with some journalism listserves quickly picking up the buzz. In addition, some American climate change activists and environmentalists initially were unsure whether to fan the flames or douse them. Some teamed up with respected scientists to quickly call the warning a false alarm, and a misleading one at that.

Flannery’s basic mistake here? He used total positive forcing – that is, just the Kyoto Protocol gases – rather than total net forcing, including negative forcings like aerosols.

Among those quickly dousing the would-be blockbuster story, along with several scientists acting individually, was

NASA scientist Gavin Schmidt on realclimate characterized what he called “a minor kerfuffle” over Flannery’s claims as resulting from a “confused and incorrect” approach to carbon dioxide equivalents.

The important number is carbon dioxide equivalent (Total), which is around 375 parts per million by volume, Schmidt wrote. “Stabilization scenarios of 450 ppmv or 550 ppmv are therefore still within reach. Claims that we have passed the first target are simply incorrect.”

“It is even more of a stretch to state that we have all of a sudden gone past the ‘dangerous’ level,” Schmidt wrote. “It is still not clear what that level is, but if you take a conventional 450 ppmv CO2 equivalent value (which will lead to a net equilibrium warming of ~ two degrees Centigrade above pre-industrial levels), we are still a number of years from that, and we have (probably) not yet committed ourselves to reaching it.”

“This is another example where people are quoting from draft reports that they have neither properly read nor understood, and for which better informed opinion is not immediately available. I wish journalists and editors would resist the temptation to jump on likes like this (though I know it’s hard). The situation is confusing enough without adding to it unintentionally.”