The Carbon brief

The website The Carbon Brief claims that it:

reports on the latest developments and media coverage of climate science and energy policy, with a particular focus on the UK. We produce news coverage, analysis and fact checks, and publish a daily and weekly email briefing. 

Its latest article, Your questions on climate sensitivity answered, strangely tells us that the value of the Climate Sensitivity, the expected rise in mean temperature of the earth’s surface given a doubling of CO2 concentration from the level immediately prior to the industrial revolution (and assuming other things are equal), doesn’t actually matter—despite saying that Climate Sensitivity is “at the heart of climate science”.

I wrote about Climate Sensitivity here, noting the astonishingly wide—uselessly wide—range of estimates. Recent studies have produced estimates at, or beneath, the lower range as stipulated by the International Panel on Climate Change (IPCC). This is unsurprising, since there has been no global warming since the mid- to late-1990s, but clearly something The Carbon Brief would rather ignore.

I made the following comment beneath the article, which attracted many ‘likes’ before it was deleted:

Why did you neglect to mention that the IPCC reduced its lower bound on climate sensitivity in its last report, and no longer feels able to offer a central estimate?

Despite the billions spent on research, climate scientists are no closer to "pinning down" this quantity "at the heart of climate science" after 25 years. Some might rate that a conspicuous failure.

I think the first sentence is a pretty reasonable question for a site that would inform members of the public with an air of authority. The second sentence is a factual observation, which many members of the public might find surprising, and some concerning; even, a “conspicuous failure”. Scientific study is meant to deliver increasing precision in our understanding of nature, of course.

According to The Carbon Brief’s comments policy, "vigorous debate is fine”. Really? I wonder why they would delete my post? Could it point to inconvenient truths?

Open letter to the Prince of Wales

Your Royal Highness,

The news media have drawn attention to a speech you gave recently in which you described climate change “deniers” as “headless chickens”. There is a lot one could say about these descriptions. Not wishing to be openly censorious and certainly without stooping to crude insult, let me merely remark that they are inapt. Instead, let me focus on your frankly admitted bafflement, that has led you to this strange description. You said:

It is baffling, I must say, that in our modern world we have such blind trust in science and technology that we all accept what science tells us about everything – until, that is, it comes to climate science.

Scientists make observations, from which they deduce laws — never more than a temporary best description of phenomena, to be refined or overthrown by subsequent observations — which can be used to make predictions about subsequent events: with greater or lesser success, according to the maturity of the field.

The key parameter in the field of investigation of the “greenhouse effect” (poor metaphor, but we’re stuck with it), which may lead to global warming due to human emissions of carbon dioxide (CO2) in particular, is the “climate sensitivity”. This is the amount by which the earth’s surface can be expected to warm, on average, given a doubling of atmospheric CO2 from pre-industrial levels. The latest report (AR5, in 2013) of the International Panel on Climate Change (IPCC) estimates that its value lies somewhere between 1.5ºC and 4.5ºC. The previous report (AR4, in 2007) estimated that the value lies between 2.0ºC and 4.5ºC. The lowering of the lower bound estimate is not surprising, given that the earth’s surface did not warm in the six-year interval between the reports (indeed, not for 12-17 years now, depending on which of the four main global temperature series you follow). What is noteworthy, is that this demonstrates that climate science is a field which is moving backwards. If you would have placed “blind trust” in climate scientists in 2007 that the climate sensitivity could not be less than 2ºC, your faith would have been misplaced. The current range of estimates is exactly the same as that given in the IPCC’s first report in 1990. Except then, the IPCC felt able to give a central estimate (of 2.5ºC) because the results of different investigators clustered around that value. Now, the IPCC does not feel able to offer a central estimate, because results are scattered. (In fact, most recent studies are towards the low end.) So climate science has made less than no progress, in 23 years of lavish funding, in narrowing down this key value, required for prognostication, where estimates vary by a factor of 3.

Now let us turn to other branches of science and technology, which you say are treated differently; in which people repose “blind trust”. Let’s take another value, the speed of light in a vacuum. Scientists say it’s 299,792,458 metres per second. Not 299,792,457 metres per second, nor 299,792,459 metres per second. And not “somewhere in the range 200-600 million metres per second, we’re not really sure”. That’s just as well, because if I get injured back-country skiing this week (I know that was also a pastime of yours), I’d like to be able to use a GPS device to report my position with a precision of a few metres, rather than “somewhere in the vicinity of planet earth”. Since I’ve relied on GPS many times, in non-life-or-death situations, I feel able to trust it, and by implication measurements of the speed of light, when the chips are down.

Just one more example. The acceleration due to gravity reported by scientists, at sea level on the equator, is 9.78 metres per second per second. Not 9.77 metres per second per second, nor 9.79. And not somewhere between 5 and 15. Precise calculations taking into account latitude and altitude can provide accurate figures for other places. Just as well, as the 747 currently conveying me across the Atlantic would either plunge to earth or go into orbit if there were uncertainty of a factor of 3. I’ve done this lots of time before though (and I know you travel by air even more than me, notwithstanding the CO2 emissions), so I have trust in the Boeing engineers and the scientists who provided them with estimates of the acceleration due to gravity.
Back to climate science. Would I trust scientists  — whose poor knowledge, of what they claim is the key variable in their field, is actually moving backwards — to inform politicians who would load the British economy with billions of pounds of costs and place millions of your future subjects in fuel poverty, even as British winters are not warming? No sir, I would not.
Respectfully yours,
Headless Chicken.