Despite the fears and, (let’s be honest, in some circles there are hopes) that extreme weather events worldwide in recent years have been due to man-made climate change, the UN/IPPCC’s latest report says, um, well …
… the human and financial toll of extreme weather events has risen. But the academic consensus [on the alleged link between extreme weather events and man’s activities] is far less certain.
There is “low confidence” [summarises BBC science reporter Richard Black] that tropical cyclones have become more frequent, “limited-to-medium evidence available” to assess whether climatic factors have changed the frequency of floods, and “low confidence” on a global scale even on whether the frequency has risen or fallen.
In terms of attribution of trends to rising greenhouse gas concentrations, the uncertainties continue.
While it is “likely” that anthropogenic influences are behind the changes in cold days and warm days, there is only “medium confidence” that they are behind changes in extreme rainfall events, and “low confidence” in attributing any changes in tropical cyclone activity to greenhouse gas emissions or anything else humanity has done…
So the hypothesis that man’s activities have caused recent extreme weather events has (take your pick) “low confidence,” “medium confidence,” or has only “limited-to-medium evidence available.” And this is the draft of UN/IPCC’s next report talking, which is, says the BBC,
explicit in laying out that the rise in impacts we’ve seen from extreme weather events cannot be laid at the door of greenhouse gas emissions: “Increasing exposure of people and economic assets is the major cause of the long-term changes in economic disaster losses (high confidence).
Or to summarise, as the UN/IPCC does:
“Long-term trends in normalized economic disaster losses cannot be reliably attributed to natural or anthropogenic climate change.”
You can’t really get more explicit than that.
And for warmists seeking evidence on which to base their cries for urgent government action to ban private activities, it just gets worse:
And for the future, the draft gives even less succour to those seeking here a new mandate for urgent action on greenhouse gas emissions, declaring: “Uncertainty in the sign of projected changes in climate extremes over the coming two to three decades is relatively large because climate change signals are expected to be relatively small compared to natural climate variability.”
Which is to say that we do know the climate is always and has always been changing. But we don’t know, and likely can’t know, if it we made it happen.
[HT Andrew Bolt]