An alarming report
Update: turns out that Flannery got it all wrong. From Real Climate:
There was a minor kerfuffle in recent days over claims by Tim Flannery (author of "The Weather Makers") that new information from the upcoming IPCC synthesis report will show that we have reached 455 ppmv CO2_equivalent 10 years ahead of schedule, with predictable implications. This is confused and incorrect, but the definitions of CO2_e, why one would use it and what the relevant level is, are all highly uncertain in many peoples' minds. So here is a quick rundown.
It's worth reading through their explanation.
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Atmospheric concentrations of carbon dioxide may already be above levels not expected for another decade or so, according to Tim Flannery:
Tim Flannery told Australian Broadcasting Corp. that an upcoming report by the U.N. Intergovernmental Panel on Climate Change will contain new data showing that the level of climate-changing gases in the atmosphere has already reached critical levels.Flannery is not a member of the IPCC, but said he based his comments on a thorough review of the technical data included in the panel's three working group reports published earlier this year.
Carola Traverso Saibante, spokeswoman for IPCC headquarters is in Geneva, said she was unable to disclose what would be in the final report synthesizing the data before it is released in November.
"What the report establishes is that the amount of greenhouse gas in the atmosphere is already above the threshold that can potentially cause dangerous climate change," Flannery told the broadcaster late Monday. "We are already at great risk of dangerous climate change, that's what these figures say. It's not next year or next decade, it's now."
Flannery, whose recent book "The Weather Makers: How Man Is Changing the Climate and What It Means for Life on Earth," made best-seller lists worldwide, said the data showed that the amount of carbon dioxide and other greenhouse gas emissions had reached about 455 parts per million by mid-2005, well ahead of scientists' previous calculations.
"We thought we'd be at that threshold within about a decade, that we had that much time," Flannery said. "I mean, that's beyond the limits of projection, beyond the worst-case scenario as we thought of it in 2001," when the last major IPCC report was issued.
It's worth getting into the numbers a bit. Projecting carbon dioxide concentrations (and other greenhouse gases-- but carbon dioxide is the most significant) into the future is an inexact science, but:
The IPCC has developed a range of scenarios, IS92af, of future greenhouse gas and aerosol precursor emissions based on assumptions concerning population and economic growth, landuse, technological changes, energy availability and fuel mix during the period 1990 to 21004. By the year 2100, carbon dioxide emissions under these scenarios are projected to be in the range of about 6 GtC5 per year, roughly equal to current emissions, to as much as 36 GtC per year, with the lower end of the IPCC range assuming low population and economic growth to 2100.
Six different scenarios, labelled A1B, A1T, A1FI, A2, B1 and B2 (the names reflect the scientific teams that made the projections) were considered, and each of projected annual CO2 emission scenarios were translated into total atmospheric carbon concentration as per this graph:
It's difficult to see on the graph what happens in the first decades of the 21st century, but if you take a look at the breakdown by decade, you'll see that even the worst case scenarios don't break the 450 parts per million level until sometime between 2020 and 2030.
| 2000 | 2010 | 2020 | 2030 | 2040 | |
| A1B | 369 | 391 | 420 | 454 | 491 |
| A1T | 369 | 394 | 422 | 455 | 491 |
| A1FI | 369 | 394 | 427 | 471 | 527 |
| A2 | 369 | 395 | 427 | 466 | 511 |
| B1 | 369 | 394 | 422 | 452 | 483 |
(various IPCC scenarios, showing expected CO2 concentrations in parts per million)
If we have already broken the 450 ppm level, 13 to 23 years before anticipated-- as Flannery says we have-- then the IPCC projections are far too conservative.
You might take a look at the top chart here and think this doesn't matter much, because atmospheric concentrations will increase far beyond 450 ppm in all the scenarios. But because CO2 sticks around in the atmosphere for a couple of hundred years, higher concentrations early on result in still higher concentrations (and therefore increased global warming) later on. Even the best case scenario (B1)shows that we need to reduce our annual emissions very, very quickly in order to achieve a levelling off at somewhere around 500 ppm. Compare this chart with the one above:
We'll have to wait for the publication of the IPCC report to see what level of annual CO2 emissions we've attained, but they're evidently at far higher levels much sooner than the lower range projections on this chart. That is, we're already well on our way into the high-range projections, which lead us to runaway global warming.
In short, the climate crisis is far more urgent than was relayed in the previous IPCC reports.
There's much more to say about this, of course, but I wanted to get at least this much out now.
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