Funny, the actual study suggests nothing of the sort. What it suggests is that climate scientists have a whole lotta ‘splainin’ to do.
The gist of the nub:
After the retreat of vast ice sheets in the Northern Hemisphere, global average temperature rose roughly 1 degree from the start of the Holocene to about 9,500 years ago, authors found. Average temperatures then plateaued for roughly 4,000 years, with the exception of two relatively short-lived spikes.
After that, things began to cool again. From about 5,500 years ago to roughly a century ago, average global surface temperature dropped 1.3 degrees.
But what concerns many scientists is what occurred next: In just the last 100 years, the average temperature has increased by 1.3 degrees. Although global temperatures of the last decade have not exceeded peak Holocene highs, they are warmer than 75% of the epoch.
Now, this is just a newspaper story, so we can’t expect much detail, but, wouldn’t it be pertinent to talk about how it came to be as warm or warmer than it is now for about 3,000 years out of the last 11.500? Because if it’s now warmer than it has been for 75% of the period, then it seems that, for 25% of the time over the past 11,500, global temperatures have been as warm or warmer than they are now. So, inquiring minds want to know: what mechanism is proposed as a cause for those past warm years, which seem to predate the current warming trend by millennia. Because those causes can’t be man-made carbon dioxide. Yet, whatever they were, we have ‘settled’ that they are not behind what’s happening now?
To be more blunt: this study shows wide enough fluctuations in global temperature during this current interglacial period to easily bracket current temperature trends – some or all of what’s going on now could be completely ‘natural’ in the sense of caused by whatever caused high temperatures in the past. So, the way science works, it is on the scientists to explain 1) what caused the warming and cooling in the past; and 2) account for how those causes are not at work in the present.* Of course, if we don’t know, then the science by definition is not settled, but most definitely unsettled. The most common truthful answer to almost all scientific questions is: we don’t know – no shame in that, that’s why we keep at it.
By the end of the century, climate warming models predict an additional increase of 2 to 11.5 degrees, due largely to carbon emissions, the study noted.
OK. That may be fascinating, but it has absolutely nothing to do with this study, which is not about models, but rather about the data that any scientifically interesting model would have to account for. But wait – the models have existed for years, sometimes decades, *before* the data they would need to account for was collected. That’s what one would, strictly speaking, call a ‘flaw’. Of the fatal variety.
“We know that there were periods in the past that were warmer than today — for example, the Cretaceous period 100 million years ago,” he said. “The real issue is the rate of change, because that’s what challenges our adaptive capacity.”
So true. When the next ice age hits, it’s going to be tough, as it seems they come and go very quickly, in less than a century, or even a decade. This quote comes from Michael Mann, who had no involvement with the study, but is the go-to guy for ‘hockey-stick’ quotes. He’s sure, the article concludes, that the deniers will dispute this. Well, as an educated layman, all I know is that a model is only as good as the assumptions built into it, and that it better account for the past before it claims to predict the future – no ‘denial’ there, just asking for science a solid high school science teacher wouldn’t flunk you on.
Compare and contrast:
This is the NYT’s coverage of the same study. This is like reporting that the Celtics beat the Heat in the second quarter – what you want to know is who won the game.
Now, headline writing is admittedly an art, but that art should be something more than uncut propaganda. For an equally valid headline would be: Study shows global temperatures often warmer than they are now over last 11,500 years. Or better and more scientific: New climate data calls models into question. and then have a real scientist explain how modeling differs and proceeds from data collection, and how building models before collecting the relevant data is not science, and that data outranks models so that models must account for them, not the other way around.
It’s almost like they’re not playing fair here.
* as Aristotle put it, what has happened is possible – so, unless we can explain otherwise, whatever has happened is in play as a possible cause of what is happening.