Almost every day some report or event is claimed as evidence of global warming. Al Gore's recent movie An Inconvenient Truth went so far as to claim that we have a "climate crisis" right now.
Do we?
It can be hard finding the real facts on climate change among all the hype.
The United Nations Intergovernmental Panel on Climate Change has a mandate to deliver a comprehensive assessment of human-induced climate change every few years, and the Fourth Assessment Report, AR4, is due for release sometime this year.
You have possibly been led to believe, given all the media headlines, that this big report was released in Paris last Friday. It wasn't.
Friday's document was just a 21-page summary of the first part of AR4, and doesn't even have a bibliography.
That's right, just a summary of a quarter of the big report.
Climate Change 2007: The Physical Science Basis -- Summary for Policy Makers is nevertheless an important document, because it details the position of many global warming experts. So what does it say?
For those who enjoy the thrill of the more extreme doomsayer predictions, the 21-page summary will be a disappointment.
For example, while Al Gore claimed that sea levels are about to rise by more than 6m, the IPCC summary indicates that sea levels have risen by just 17cm and may rise by no more than another 18cm, certainly no more than 59cm by 2099.
The IPCC scientists predict temperatures will increase by 0.2°C per decade for the next two decades, and that by the end of the century temperatures may have increased by as much as 4°C or as little as 1.8°C.
The 21-page summary indicates the world has warmed by 0.74°C over the past 100 years. To put this in perspective, temperatures in Brisbane regularly fluctuate by as much as 10°C in one day.
The IPCC summary explains that at the Arctic temperatures have increased at almost twice the global average, while at the Antarctic there has been no warming. That's right. No global warming at the South Pole.
The IPCC summary indicates there is no clear trend in numbers of cyclones, but their intensity has increased in the North Atlantic since 1970 and on balance there are likely to be more-intense cyclones in the future.
The IPCC summary does not explain why regions such as southeast Queensland have missed out, but perhaps this and many other issues will be detailed in the actual report when it is published in May.
It is unusual for the summary of a scientific report to be released before the actual report. Then again it is unusual for a report to be written by 600 scientists and reviewed by more than 113 governments; the process so far for just part one of AR4.
Before May, all the contributing scientists are expected to refine the individual chapters in the report to make sure they all accord with the agreed summary.
Much has been written by philosophers about how scientists can get stuck within particular paradigms, unable to break free from the groupthink. Indeed, while it is useful to have a consensus from the United Nations on global warming, there must also be a place for dissent and debate.
But the IPCC summary glosses over various anomalies. For example, while the global trend has been one of warming, a plot of mean temperatures since 1998 shows that there has been no warming since then, now eight years later.
The IPCC summary does not acknowledge the current downward trend, which may or may not prove to be just a blip in the scheme of things.
All in all, the IPCC summary paints a picture of a warming world, but I couldn't find a climate crisis.
I am looking forward to reading the report in May, and let's hope it rains on Brisbane in the meantime.
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