Overstated claims

...by authors of 'earth system science' studies after publications.

This has been AustinGreen's beef, at least I shall say it in that way.

But once in a while it gets to me too.

There is a darn good paper in Nature about trees and drought sensitivity, and I was real happy with that. But now in CNN

Drought-stressed trees face race to adapt - CNN.com

Those authors (and a few others) go a bit further than I'd like about the future of trees.

Another one about calcifying marine organisms was recently brought up by Bob Wilson.

What I'd like to hear, when authors are extrapolating results (perhaps egged on by the interviewing journalist - who knows?) , a bit more perspective.

Like this: the Paleocene-Eocene Thermal Maximum (PETM) around 55 Mya was hot. really hot. At that time, land plants were diversifying really fast. Angiosperms 'taking over' from gymnosperms, all sorts of wacky new flowers, the whole bit. Somehow or other, a very large proportion got through that. Were there also super droughts? I do not know, but land plants sailed right through. I have no fear that must are going to sail through this as well. There probably will be some extinctions if climate change moves faster than particular species can move. Or if they go uphill and 'run out of mountain' (which is another heavily published topic).

In PETM and earlier, there is evidence of episodes where ocean chemistry had big changes, including substantial pH reductions. But here, the critters we are talking about (molluscs, coccolithophores, coralline algae and many fish) are old. Really old. Phytoplankton probably the oldest, but many of those others are early Cambrian. Representatives of those groups, again, have sailed through all that. 600 million years...

I am not denying the 5(or 6) major extinction events. But at some taxonomic level (above species), plant and animal life is really durable. Just keep that in mind next time you read a gloomy author interview in the media.

Lycopsid trees, trilobites and dinosaurs were, in their own ways, probably the most successful organisms ever on earth. All gone now, which surely shows that the mighty can fall, but darn it, life is really durable.

 

I don't agree that I stepped over a line. I try to point out some examples where scientists step over a line when describing implications of their studies far outside the 'space' that was studied.

For the 'biophysics and anatomy of drought resistance' , the Chaot et al. study as published was so darn good. I love that thing! Made the CNN interview harder for me to accept. If the paper had been mediocre I probably would not care that much.

Increasing tree mortality has been observed on all continents ('cept Antarctica of course). Van Mantgem and Allen are your go-to authors. It is by no means insignificant.

Actually, both these things are happening: Trees are growing faster (CO2 and probably nitrogen and warmth) and they are dying faster (drought, insects, disease). There is a lot to be studied about it, and we are probably still missing some important ideas.

The real line not to be crossed for trees is right around 40 cm rain per year. If your chunk of land is 'better irrigated' than that, there will be trees. Maybe not the species you want, but...

If your chunk of land is presently above 40 cm rain per year, and climate change puts it below, no more trees. There may be hope that Chaot et al.'s study could point the way to 'bioengineer' trees that can get by on a bit less. I imagine we'll need them, and I'd rather see that in an interview than "Jeez we're all gonna die'

I be overly dramatic? Likely so. But I tend to hold my sciencey friends to high standards.

 

One of my big favorites there Jimbo! In years with heavy seed production (called mast years) various indian groups in Sierra Nevada mtns fought wars to control harvest areas.

Yeah I know they are not indians. native Americans. Maybe Chinese having made The Really Long March.

A close species exists along the CH/ N Korea border now, and the nuts are every bit as tasty.

 

Good pictures. Lovelock 13 cm, Elko 24 cm annual precip. (I looked it up) What I had more in mind was Silver City, NM @41 cm. There the pinions grow a lot closer together, though still not a closed canopy.

Actually not a simple thing to define a tree-minimum rainfall. The Abizzia genus can apparently get by on 25 cm, which I find amazing. Surely it is drought-deciduous under those circumstances.

If the land is 'shaped right', soil water can concentrate in small areas and there tree roots will find enough. This is an unexpected benefit of soil erosion; creating such pockets, then a tree jumps in and then erosion is slowed.

The Hohokam in (what is now) Arizona shaped the land by hand, though their interest was corn beans squash, not trees. I was taught (in ye olden days) that drought eventually snuffed them, but the wiki page suggests that mid-14th century flooding blew out their canal works.

All very interesting and suggesting again that we need to re-examine our interpretations when new ideas come along. I shall make that my new philosophy. Along with not over-extrapolating from the (perfectly good) data that one does have, which is where I began this.

 

I add another, but with no plan to do so again every time I feel that another overstatement is just over-over-over. This one comes from a UNESCO document intended to inform school kids:

http://www.unesco.org.uk/uploads/UKNC%20IYB%20Schools%20Pack.pdf

I find very little to disagree with in it. Except for this on page 5:

"Some researchers have predicted that for every one degree centigrade temperature rise that takes place, 10% of species will become extinct globally."

There is no literature reference, but aappropriate here because this is for kids who would not benefit from that. But beginning with the (poor form) 'Some researchers' the claim (containing the word 'will') simply sounds goofy. To me it does.

I have not found any published research that supports the claim. The PETM was not like that, as far as the fossil record has revealed. The (earlier) dinosaur extinction may have been like something that, but we also have to posit a major, persistent shortage of food (plants) for their extinction. Not just a bump in T, see? Beyond that, dinosaurs' 'stepping aside' opened the door for mammals to become something more than rats in the night. Something more, like you and me. Gotta love that! Thanks, asteroid and volcanoes erupting through coal deposits and whatever did the job.

There have been many species extinctions in the last few 100s years. But as AustinG said here above, much of that can be readily ascribed to humans altering habitats. North American passenger pigeons represent another type, that can be summarized as 'we killed them all'.

I have no fundamental objection to this UNESCO document as a teaching tool, except that the inclusion above is goofy and flies in the face of reason. It opens the door wide for debunkers to simply dismiss the whole thing, which is otherwise quite reasonable.

Overstating your case is never a good idea; science is too 'self-correcting' to allow for that. The IPCC AR4 did so, famously, for a 2035 'Himalayan meltdown' and in several other minor ways. Are those things sufficient cause to throw the whole thing out? Obviously not, but overstatement does not reflect well upon scientists.

To soften the blow, I offer just one more:
“Comparing climate projections to observations up to 2011”
Rahmstorf S Foster G Cazenave A 2012
Environmental Research Letters 7: 044035
doi:10.1088/1748-9326/7/4/044035

My short summary: both air T and sea-level trends until now have exceeded what the climate models have predicted. See figures 2 and 3. Importantly, there are no wild future predictions. Simply an attempt to compare where we are now, to all that modeling stuff. Nice. No goofy extrapolations. Just a simple implicit message, that IPCC AR4 turns out to have been overly cautious.

What AR5 will bring remains to be seen.

 

Thanks for that. Maybe the darn models aren't so bad after all

But since you posted the figure, look at what the models still can't do - the unusually warm- or cool-air years, most closely related to ENSO. This still seems to me an Achilles' heel. If there is a 60-year slosh in the oceans we don't understand, then maybe 'hamstring' is a better description.

I feel like we are still kinda stuck. A wide range of observations show consistent patterns: Continental ice loss, air T, air humidity (recently added to the list at Mojo's behest) sea level, ocean heat content, species' phenology and redistributions, and a few others I doubtless missed.

Physics still works: IR-absorbing gases absorb, and the (rather few) measurements of IR getting to the ground show that less of it is. Those studies I did not burden you with previously, look for Philipona et al 2004 and 2012, and Wang and Liang 2009. Or let me know if you can't find them. Also, Clausius-Clapeyron shows that warmer air holds more water, and that bit still works as well.

All those things are stubbornly consistent. But the coupled climate models can't seem to do variations in ocean heat storage, and the 1997-1998 El Nino is just the latest zinger. So,'no warming since 1998' is not just a misstatement, it misses the real point: we can't model marine dynamics.

So, will we stay stuck at not monetizing fossil-C emissions because of that? and is it prudent to remain so?