In the game of alarmist whack-a-mole the latest and greatest sudden certainty is that, as Reuters “Sustainable Switch” emailed, “Earth’s life-support systems at tipping point”. See, “the world had now crossed six of nine ‘planetary boundaries’” which you might not have noticed but apparently we’re now two-thirds of the way to being dead. Or something. The metaphors keep changing so it’s hard to know what exactly to expect.

Admittedly the story is good clickbait. AFP, which once had the gall to fact-check us on a simple statement of fact, roared:

“Human activity and appetites have weakened Earth's resilience, pushing it far beyond the ‘safe operating space’ that keeps the world liveable for most species, including our own, a landmark study said Wednesday.”

Which a sane person would take to mean most species were now dying off in a world no longer “livable”, indeed “far beyond” such a thing. Unless words have no meaning.

Reuters “Sustainable Switch” mostly just killed humans off, insisting that we got:

“Stark news to end on this week as an international team of 29 experts found that the Earth is now ‘well outside of the safe operating space for humanity’ due to human activity.”

Which no doubt is why the population keeps growing and people keep living longer, healthier lives. Though in saying that we are relying on specific measurable evidence rather than feverish metaphors, in keeping with Lord Palmerstone’s dictum, “Half the wrong conclusions at which mankind arrive are reached by the abuse of metaphors”. And by the collision of incompatible and meaningless metaphors, like picturing human “appetites” weakening Earth’s “resilience” while also “pushing” it outside a “safe space.”

But we should, as they say, follow the science. Did this team of experts secure widespread agreement among colleagues as to the existence and location of these “boundaries” beyond which we, or everything, would die, before moving to the onerous task of determining if we really were “outside” them and on what specific grounds?

Did at least they secure widespread agreement as to their existence and transgression simultaneously? Or is it just twenty-nine predictably excitable people being predictably excitable to the predictable applause of excitable journalists?

To use a highway engineering metaphor, when construction firms place barriers next to steep slopes there is a lot of careful, general analysis of the conditions under which a motor vehicle will tip and plunge, and of the sorts of barriers that can stop a car or bus given its mass, velocity, angle of impact and so on. And if these people tell you well, on this curve here you’d need a type 47E fence 40 metres long with 15-centimetre posts sunk three feet into 50-kilo concrete blocs to stop a sedan going 85 km/h, they know whereof they speak.

When alarmists speak of planetary boundaries it conjures up images of similar grounded knowledge. But wrongly. Like the metaphor of a “tipping point”, it’s the result of lazy thinking rather than deliberate deceit.

Indeed, Reuters concedes that:

“The authors said crossing the boundaries did not represent a tipping point where human civilization would just crash but could bring irreversible shifts in the Earth’s support systems.”

Which means what exactly? For instance one of the “boundaries” evidently involves “the use and availability of fresh water”. And we’re all for water. But on a planet with a vast water cycle and a land surface ranging from permanent arid deserts to soaking wet rainforests, how can the supply of fresh water everywhere be reduced to one thing and furthermore be judged to be irreversibly “shifting”?

Another “boundary” is supposedly “climate change”. But as we never tire of noting, climate changes all the time. It seems that 2.58 million years ago the Earth made a semi-irreversible shift into an Ice Age, in the sense that no subsequent warming has come anywhere close to melting the polar ice. But is it really irreversible, or might the planet return to its normal condition some 10°C warmer than it is now? They don’t know.

What they do know, and if not we will tell them, is that there does seem to be a lot of dynamic resilience in the Earth’s climate. When it cools, it rarely goes so far as to become a snowball, thank goodness, and when it warms, it normally seems to stop around 22°C.

On the subject of evidence, it’s also worth blowing a raspberry at the claim that:

“In a ‘health check’ for the entire planet published in the Science Advances journal, an international team of 29 experts found that the Earth is now ‘well outside of the safe operating space for humanity’ due to human activity.”

For despite the tone of sombre respectability, the fact is that the world’s human population is higher than it has ever been, considerably higher in fact, due in part to the surge in well-being in Africa, which had under 400 million people in 1973, less than 10% of the world’s total, but is now at over 1.3 billion and 20%. And for those alarmists who flunked geography, we’d like to point out that Africa is the big one pointing north-south underneath Europe whose widest part is just north of … what’s this? The equator? Band of hotness round Earth’s middle, baked, scorched, boiled and rhetorically incinerated by climate heating?

Surely to assert that the planet is well outside the “safe operating space for humanity” you should have some evidence that people are in trouble rather than enjoying unprecedented life expectancy and personal income even though there are more of us than ever. Or some caution with respect to the metaphors that shape your thinking.

The entire paper seems to be something of a grab bag of trendy issues:

“The scientists sounded the alarm about increasing deforestation, the excessive consumption of plants for fuel, and the proliferation of manmade products like plastic, genetically modified organisms and synthetic chemicals.”

Many of these things might be bad, or at least to be approached with caution. But “the excessive consumption of plants for fuel” is not going to end life on Earth. And deforestation is bad but trees do grow back. In fact in North America there are a lot more forests than there were a century ago when so much land was farmed to produce fodder for the horses that the ingenious internal combustion engine then displaced.

If you can bear it, here’s the paper abstract:

“This planetary boundaries framework update finds that six of the nine boundaries are transgressed, suggesting that Earth is now well outside of the safe operating space for humanity. Ocean acidification is close to being breached, while aerosol loading regionally exceeds the boundary. Stratospheric ozone levels have slightly recovered. The transgression level has increased for all boundaries earlier identified as overstepped. As primary production drives Earth system biosphere functions, human appropriation of net primary production is proposed as a control variable for functional biosphere integrity. This boundary is also transgressed. Earth system modeling of different levels of the transgression of the climate and land system change boundaries illustrates that these anthropogenic impacts on Earth system must be considered in a systemic context.”

Forgive us our transgressions … if you can figure out what any of it actually means. Right down to “control variable for functional biosphere integrity”. Where was that when the end-of-Cretaceous asteroid hit, or the Younger Dryas, or indeed the Pleistocene started and the ice came? Where would it be if atmospheric CO2 fell to 150 ppm, for natural reasons or due to some hideously ill-advised geoengineering scheme to save us from phantom “climate breakdown”, and all C3 photosynthesis plants died? And what’s a “systemic context” and what other contexts might “Earth system modeling” have considered?

Reuters peddles much equally lazy gooblahoy, such as “The atmospheric concentration of carbon dioxide, the main greenhouse gas, has risen to around 417 parts per million, significantly higher than the safe level of 350 ppm” as if this “safe level” were like the medically well-established “safe level” for breathing the stuff. And then:

“The current rate of species extinction is also estimated to be at least tens of times faster than the average rate over the past 10 million years, meaning the planet has already crossed the safe boundary for genetic diversity.”

Pray tell, what authority established that ten times the average extinction rate over the past 10 million years was the “safe boundary for genetic diversity”? Nobody.

Never mind. The piece winds up quoting the totally impartial scientist who says, namely “Johan Rockström, the study’s co-author and director of the Potsdam Institute for Climate Impact Research” that “It is a complete failure ...and it’s a large risk... We’re still following a pathway that takes us unequivocally to disaster.”

A pathway across nine boundaries to a tipping point. Got it.