Tag Archives: atmospheric co2 concentration

Stopped clocks, bad debts and climate sceptics: or why the latest paper on climate sensitivity does not vindicate the sceptics (nor suggests complacency)

clock_broke

For those who pay attention to minutiae of the climate debate, you may have noticed the denial-blog-sphere is all-a-flutter with claims of “Sceptics proven right.”

This source of this self-congratulation among the sceptics is a recently published paper in Nature Geoscience titled Energy budget constraints on climate response by Alexander Otto et al [doi:10.1038/ngeo1836].

I was able to source a copy of the paper and took the time to appraise how it could possibly be the source of so much sceptic excitement.

Let me quote from the paper so that you may judge whether-or-not the sceptics have been vindicated:  

“The rate of global mean warming has been lower over the past decade than previously. It has been argued that this observation might require a downwards revision of estimates of equilibrium climate sensitivity, that is, the long-term (equilibrium) temperature response to a doubling of atmospheric CO2 concentrations…”

The paper notes:

“The most likely value of equilibrium climate sensitivity based on the energy budget of the most recent decade is 2.0 °C, with a 5–95% confidence interval of 1.2–3.9 °C…”

From this, sceptics have claimed the death knell of climate science. Having read it, the take home points are for me are:

  • the oceans have been sequestering a great deal of heat – much more and much more rapidly than we thought 
  • that will come to an end at some point in the future, with the heat coming back out as the climate system tries to reach a point of equilibrium (note: as the atmosphere and oceans exchange heat)
  • the rate of warming for the last decade has been at the lower end of model projections
  • thus in the short-term the climate may warm 20% more slowly than previously expected (i.e. transient climate response)
  • even though we may not see some of the extremes predicted in earlier models, a doubling of atmospheric CO2 concentration opens the door for an average temperature increase of +/- 4.0C.

Good news story and the death knell of the climate conspiracy?

Hardly.

The research is not that a radical departure from the results of climate science, but consistent with other work within the field.

It is also worth noting the paper does not take into consideration tipping points or other anticipated positive feedback mechanisms such as increased methane emissions – the release of vast quantities of this most potent greenhouse gas from beneath the Arctic tundra due to warming.

A small and maybe irrelevant point? Must likely not.

Indeed there are a quite few nasty surprises like methane out-gassing lurking out there – things known but generally avoided in many models (the planets decreasing albedo effect as the extent of the Arctic ice decreases anyone – anyone?).

It will be worth watching the research on climate sensitivity over the coming years: at least form the perspective of how policy makers, sceptics and the public react to this informaiton.

Just how fast, and how extreme, will the warming be?

A very interesting question indeed.  

Bad “climate” debts accumulating: no time for complacency

A 2.0C-4.0C increase in average temperatures will have a significant impact on large parts of the globe, if not devastating large swathes of it.

As the oceans draw down heat it will fuel their thermal expansion, a major driver of projected sea level rise. Nor will the oceans continue to do humanity a favour by acting as endless sink for the additional heat we’re adding to the climate system.

Crop production around the mid-latitudes is going to be hit hard, which incidentally is where most of humanity resides. Remember the aforementioned sea level rise? Many millions in the mid-latitudes will be forced to relocate.

But hey, wheat production will increasingly shift to Canada and the Arctic circle. You win some, lose some right?

Like avoiding a bad debt by taking out another high interest credit card to cover your repayments, this warming is going to raise its ugly head in the future. One may avoid paying your debts in the short-term, but at some point the Sheriff will come a-knocking and take the keys to your car and what personal property you have.

Likewise, the climate will come and “ask” us for the debt we “owe it”.

Things like coastal cities and productive farmlands will be the collateral confiscated to service the “warming debt” our species is accumulating.

Perhaps we’ve gained a little extra time – a tiny window of opportunity really – to bring down greenhouse gas emissions. Perhaps we have more time to plan adaptation measures.

Whatever the case, the window for action is still narrow: this research is not cause for complacency.

Sadly I fear laggard policy makers and the mischievous will see it as such, and continue to push the cause of inaction.

Deep time, deep history, climate change and living through interesting times

Let’s also place this “pause in warming” in context.

In geologic terms, the rapid increase in atmospheric CO2 and the warming trend is unprecedented in the planet’s history.

It is vital we stop thinking in terms of a climate change as the up-or-down temperature swings of a particular decade. We accuse sceptics of cherry picking; likewise we need to remove our own myopic filters.

We need to pay far closer attention to the paleoclimate record: as James Hansen has recently argued, we cannot fully appreciate the profound changes the planet is undergoing without drawing on the lessons of the geologic past.

Nor should we disregard the warming oceans, the decline of Arctic sea ice and the increasing levels of CO2 in the atmosphere – and the many other metrics – all point to the same conclusion: warming has not stopped.

Perhaps it is the own cognitive limitations and the transient nature of how we experience time that creates such a short-sighted and myopic view of climate change.

I suggest we think in terms of both deep time and deep history.

2.5 billion years from now, should our descendants or a successor species of comparable intelligence dig into the Earth’s crust they’ll find evidence of our civilisation: but not in artifacts or fossils.

Instead they will note the abrupt disappearance of species in the fossil record (evidence of a mass extinction event) and the changed chemical composition of ocean floor and terrestrial sediments.

The evidence will point to a warmer world relative to other periods within geologic history. Billions of years into the future, a faint but still distinguishable trace of humanity’s impact will be evident. 

That’s how profound and long-lasting the changes humanity has wrought are.

We’ve not seen this level of CO2 in the atmosphere in millions of years: most recently during the mid-Pliocene (5.3-2.5 million years ago).

At that point the average temperature was 3.0C-4.0C higher, while sea levels were 25 meters higher.

However, we won’t have the luxury of billions of years of perspective to ponder what happened: we’ll be living through those profound planet-shaping and epoch-defining changes.

Actually, we are living through those planet-shaping and epoch-defining changes.

Of stopped clocks and claims the planet is no longer warming

What also interests me is the sceptic response.

As anticipated, they’ve misinterpreted the paper and claimed it as vindication of their views.

My response to that is even a stopped clock gives the right time twice a day.

It’s well understood the rate of temperature change has varied over the last 150 years: to claim such a pause is evidence against warming is to merely be right by chance, and not for the reasons the sceptics likes to claim.

The sceptics are in no way vindicated: a slower rise in land temperatures does not imply climate change has stopped, or was “exaggerated”.

Indeed, lead author of the paper Alexander Otto makes that point in an interview with The Guardian:

“Otto said that this most recent pattern could not be taken as evidence that climate change has stopped. “Given the noise in the climate and temperature system, you would need to see a much longer period of any pause in order to draw the conclusion that global warming was not occurring,” he said. Such a period could be as long as 40 years of the climate record, he said…”

Sage advice the sceptics are won’t to ignore.

Which of course they do…

Perth’s resident climate sceptic and conspiracy theorist Jo Nova is the most self-congratulatory, breathlessly announcing they (sceptics) where right all along:

I think the climate sensitivity figure is still too high but it’s good to see estimates being revised in the right direction. Reality bites back. The deniers were ahead of the climate experts. We said the models were exaggerating and we were right.

Andrew Bolt in his usual fashion is not even close to being wrong claiming “alarmists” have finally admitted defeat:

Sure, warmists exaggerated the temperature rise so far, The Age finally admits. But we still have to believe they’ll be right about the apocalypse to come:

The rate of global warming caused by rising greenhouse gas levels could be slower than previously thought, but will still result in the same eventual higher temperatures as earlier forecast, new research has found.

Note also the story suggests there has been a “rate of global warming” over the past decade, without actually telling you what it is. If the reporter did, he’d have to admit there’s been no warming at all…

Bolt completely misrepresents the results of this paper; his view that there has been no warming is completely contradicted by Otto’s statements – whose work Bolt seeks to misappropriate to support his fallacious argument.

Bolt also gets it spectacularly wrong in his first sentence: no one is revising historical temperature increases down (as his wording implies), they are revising the short-term (i.e. transient) rise in the global temperature average slightly down over the coming decades.

Global warming has not stopped; it just may have hit a very small and minor speed bump. It is virtually certain to pick up speed again. 

Thus it would seem Mr. Bolt is struggling with such basic concepts as the past and future. But, hey like whatever Andrew: us warmists have always got it wrong.

I’m sure he got his “facts” from Watts up with That? or some other climate sceptic blog and they fitted nicely with his prejudices – he tags the post “Dud predictions” without fully appreciating what he is posting.  

Sorry to disappoint Andrew, but we’re still heading towards a much warmer world.

The sceptic response: the enemy of my enemy is the fact we can cherry pick

What’s remarkable here is not the paper itself, but the sceptic response. Indeed, their response is ripe with irony.

For decades sceptics have claimed the models constructed by climate scientists are unreliable and not to be trusted.

And yet, when a model or a piece of research shares the barest hint of concordance with their views they proclaim it as a victory for sceptics.

It seems the old adage “the enemy of my enemy is my friend” applies. 

To paraphrase in sceptic terms, “the enemy of my enemy is the facts I can cherry pick”.

Sceptic victory?

Hardly.

Tagged , , , ,
%d bloggers like this: