Category Archives: climate

climate, Geography, Geology, History of Science

A Groovy Kind of Rock

June 3, 2011 Tim Jones 4 Comments

Glacier scarred morain rock near Llanberis (Photo:Tim Jones) — Boulder

A Short Vacation

On a winding stretch of the A5 road from North Wales to London – around Betys-y-coed and Llangollen – mountain scenery combined with the challenge of balancing speed, driver satisfaction, and passenger nausea makes the journey almost enjoyable. On the other hand, the interminably boring alternations of dual-carriageway and roundabouts that follow – between Oswestry and Shrewsbury – are a recipe for brain death.

Except, that is, one day last week, returning prematurely from a weather-killed ‘Welsh Break’, my mind buzzed over two critical questions the whole trip: What would our broken tent cost to fix? And why did the grooves on that boulder point to the North East?

Well spotted that woman at the back; this is a post where I obsess about a rock.

Snowdon (Photo:Tim Jones) — Boulder and Snowdon

Location relative to Wales — Location in Wales

locationmap — Location relative to Llanberis

The boulder in question sits about a half mile down the old Rhyd Ddu road outside Llanberis in Snowdonia. Its top surface is covered with North East-facing parallel grooves.

And that’s puzzling, because it looks like a moraine boulder dropped by a glacier, in an area where – having walked these valleys for years – I always assumed the ice had flowed towards the North West, away from Snowdon. Seeing as though the scrape marks left by glaciers – which is almost certainly what these are – align with the direction of glacial flow, something is amiss.

At this point, lest I raise galactic doubt and uncertainty beyond already dangerous levels, as Douglas Adams might say, rest assured this is all sorted – after a fashion but in a reasonably scientific way – by the end of the post. I also got a new tent pole: £15 – thanks for asking.

South Sea Wales

The relevant history starts around 400 million years ago with successive phases of volcanism, weathering, and glaciation (plus some folding and other geological processes). When the oceanic plate of Iapetus undercut the adjacent tectonic plate of Avalonian – all in the Southern Hemisphere back then – the resulting subduction generated enough heat for volcanoes to punch through Avalonia and form the upland region we now call Snowdonia¹.

476px-Baltica-Laurentia_Caradoc_EN — Source: Wikicommons

normal_ian-symbol-plate-tectonics-subduction-zone-and-mid-ocean-ridge476 — Subduction Zone (Source:IAN Symbol Libraries)

The ensuing millenia saw wind, rain, and rivers transform the resulting mountain range from Himalayan grandeur to the more modest heights we see today; yet some of the most dramatic re-modelling was reserved for only the last 20,000 years or so. And it was caused by ice.

20,000 years ago we were at the peak of a major ice-age that buried the whole region under 1.4 km of ice, with just the tops of the highest mountains poking out. Moving under gravity, glaciers of rock-bearing ice flowed down the river valleys, gouging out the Llanberis, Nant Ffrancon, and other steep-walled passes, cutting through hard volcanic rock in a series of breaches, and scooping out rounded recesses, or cwms (known as corries in Scotland).

Llanberis Pass on the right, Cwm Brwynog to the left

View down Llanberis Pass from Llanberis (Photo: Tim Jones) — View down Llanberis Pass from Llanberis

Chunks of rock, liberated by repeated melting and expansion of ice, or plucked out by other rocks, joined the glacier and travelled as an abrasive slurry beneath the ice – scoring anything in their path, before being released as ‘moraine’ when the glacier descended to a warmer altitude or the general climate warmed up sufficiently for the ice to melt.

Boulders falling on the surface of the glacier were likewise dumped, sometimes in incongruous isolation, their angular forms undamaged – like this one just off the Snowdon Ranger Path:

Moraine boulder east of Snowdon near Snowdon Ranger Path / Llyn Ffynnon-y-gwas

A Popular Destination

Glacier-scarred morain rock near Llanberis, North Wales. Photo:Tim Jones — Did Darwin or Huxley pause at this one?

No shortage of historical figures are associated with glaciation and its geographical consequences, including: Louis Agassiz, Charles Lyell, Charles Darwin, Alfred Russel-Wallace, John Tyndall and Thomas Henry Huxley. Agassiz observed glaciers in Switzerland, and in 1840 was the first to suggest similar processes had operated in the upland areas of Britain (an assertion on which he was closely supported by William Buckland and Charles Lyell.)

Charles Darwin knew the region well²:

“I cannot imagine a more instructive and interesting lesson for any one who wishes (as I did) to learn the effects produced by the passage of glaciers, than to ascend a mountain like one of those south of the upper lake of Llanberis, constituted of the same kind of rock and similarly stratified, from top to bottom. The lower portions consist entirely of convex domes or bosses of naked rock generally smoothed, but with their steep faces often deeply scored in nearly horizontal lines, and with their summits occasionally crowned by perched boulders of foreign rock.”

The glacial boulders of North Wales, with their strange grooving, made a particular impression on Alfred Russel Wallace, the co-discover with Charles Darwin of evolution; commenting in his paper Ice Marks in North Wales³:

“..it frequently happens that grooves or scratches are made upon the rocks by the hard materials imbedded in the bottom or sides of the glacier. Owing to the enormous weight and slow motion of glaciers, they move with great steadiness, and thus the markings on rock-surfaces are almost straight lines parallel to each other, and show the direction in which the glacier moved.”

and:

“Nothing is more striking than to trace for the first time over miles of country these mysterious lines, ruled upon the hardest rocks, and always pointing in the same direction.”

Suddenly I feel less alone in my fascination.

In his hugely popular textbook on physical geography – Physiography⁴ – Thomas Huxley describes how glaciers flow over exposed bedrock to produce characteristic Roches Moutonnees formations (sheep-backs), complete with parallel striations:

rochesmoutonnees — Roches Moutonnees, Colorado (from Huxley's Physiography, p.162, 1878)

The Mystery Solved?

But back now to the North West / North East question; a closer look at the Ordnance Survey and Google 3D map projections suggests an answer.

For directly to the South West of our boulder is a more local gouging of the hills in the form of Cwm Dwythwch and its attendant lake – Llyn Dwythwch, suggesting the area was subject to local glaciation running perpendicular to the main ice-flow from Snowdon. Indeed, the feature is discussed in a paper from the 1950s describing the glaciation as a distinct event, separated from the main ice-flows by 10,000 years in the last period of UK glaciation – the ‘Loch Lomond Advance’. The cwm certainly aligns with our boulder (pink X marks the spot):

Things are even clearer in glorious Google 3D, North at top:

or looking toward Snowdon:

In Late Glacial Cwm Glaciers in Wales⁵, Brian Seddon references Cwm Dwythwch and 32 other cwms or cirques in the region arguing they developed from snow and ice preferentially deposited on the sun-sheltered North and North Eastern faces of hillsides, assisted by snow-drifting induced by South Westerly prevailing winds (like we have today). Seddon recorded the moraine fields of 33 such cirques, plotting their altitude(circles) and aspect(radii) to illustrate the dominance of North/North East facing cwms. He placed the lowest extent of moraines in the Snowdon Group, containing Cwm Dwythwch, at 275 metres, which is above, but not far off, our boulder’s height at 240 metres. Maybe he didn’t count every individual boulder at the boundary? That Snowdonia was formed by a mix of ice-cap and localised glaciation is now widely accepted^6,7.

All of which, in conclusion, suggests our boulder most likely started life as a volcanic outcrop at the top of Cwm Dwthwch, was carried to its present position by a glacier in a secondary period of low temperatures and glaciation around 10,000 years ago, and picked up abrasions as it was overrun or carried in the North Easterly underflow.

All that with three qualifiers: (a) it’s not 100% certain the boulder is not actually an outcrop of bedrock (need to take a closer look next visit!); in which case it’s fair to assume it was simply overrun by the glacier; and (b) it’s possible the boulder was carried down from Snowdon in the first glacial episode and subsequently overrun by the secondary glacier (again, more research); or even (c) the boulder was scarred in the first episode and somehow got spun around 90 degrees just to fool us.

Clearly no rest for the rigorous – or obsessive weekend geographers – it would seem.

p.s. If any seasoned geologists out there want to put me right / out of my misery, please feel free :-).

basecamp — Basecamp with pre-broken tent

References / Sources

1. Rock Trails, Snowdonia: A Hillwalker’s Guide to the Geology and Scenery. Gannon, Paul. Pesda Press, 2008

2. Notes on the Effects produced by the Ancient Glaciers of Caernarvonshire, and on the Boulders transported by Floating Ice, Charles Darwin, The Edinburgh New Philosophical Journal, 1842, p.362.

3. Ice Marks in North Wales (With a Sketch of Glacial Theories and Controversies) Alfred Russel Wallace, Quarterly Journal of Science, January 1867

4. Physiography: An Introduction to the Study of Nature. T.H.Huxley, Macmillan, 1878, p.162.

5. Late Glacial Cwm Glaciers in Wales. Brian Seddon, Journal of Glaciology, 1957. In International Glaciological Journal, Volume 3, Issue 22 pp.94-96

6. The last glaciers (Loch Lomond Advance) in Snowdonia, North Wales. Gray JM 1982. Geological. Journal 17: 111-133.

7. Allometric development of glacial cirque form: Geological, relief and regional effects on the cirques of Wales, Ian S. Evans, Geomorphology Issues 3-4, 1986

8. The Early History of Glacial Theory in British Geology. Bert Hansen, Journal of Glaciology, Vol 9, No.55, 1970.

animals, climate, conservation, environment, events

One Forest Fire Too Close to Home

October 9, 2009 Tim Jones 4 Comments

South Western California is one of the world’s most bio-diverse habitats. The San Gabriel Mountains, north of Los Angeles and south of the Mojave desert, are home to large mammals: including deer, bear, mountain lion and bobcat. Raccoon and skunk are stealthy night-time visitors to the back gardens of residents, who by day enjoy the company of humming birds, golden oriels and scrub jays. Lizards scamper on sun-baked rocks, while praying mantis sway, poised – for lunch.

If this all sounds a little wistful, it’s because I’ve enjoyed this region at its best in a form that now – literally – no longer exists. For in August and September of this year, 250 square miles of it was destroyed in one of the largest forest fires California has experienced in modern times. Here is a time-lapse video of the fire spreading behind NASA JPL, and below that a picture of the local aftermath taken by my wife, Erin.

: Scorched Earth left by the Station Fire in the San Gabriel Mountains (photo: Erin Conel Jones)

I have to confess that while many thousands of wild animals – including some endangered species – perished in the fire, my immediate thoughts were for my in-laws. Living in the foothills north of Pasadena, they sat out their fire under a mandatory evacuation order, pondering the fate of house and home in front of a hotel TV in downtown LA.

Thankfully, save for a messy rainfall of ash in the yard, this personal story ended happily (although we remain girded for de-vegetated mudslides induced by the winter rains). The same cannot be said for the local fauna and flora – or for that matter the carbon footprint of California.

Animals caught in forest fires may run away, bury themselves, or burn and die. The so-called Station Fire (it started near a ranger station) was unusually intense and fast-moving, making it confusing and difficult to out-run; the charred carcasses of normally brisk bears, deer, and mountain lions were found amongst the smouldering tree stumps.

Those animals sufficiently fleet of foot to escape the immediate effects of a fire still face loss of habitat and possible starvation. On this occasion, the local populace was put on alert for more frequent visitations from displaced animals and asked to cut some slack for the potentially more dangerous coyote (i.e. don’t just shoot it).

Smaller land animals, such as the endangered Mountain Red-legged Frog; and fish like the Speckled Dace and Arroyo Chub may yet face their greatest challenge with the arrival of winter flood-waters, when ground unsupported by vegetation, but loaded with harmful rock fragments, will wash into fast flowing stream beds.

We might stand back at this point and declare the Station Fire to be just another part of a natural cycle that has developed over the eons. Whether a fire is started through an act of arson (as suspected in this case) or by lightning, forest fires invigorate fire-adapted ecosystems – don’t they?

The answer is yes and no – and this debate won’t end any time soon. The issues centre on the degree and speed with which man has altered the region’s natural ecosystem.

Fire-suppression policies, whereby unnaturally high fuel stocks are allowed to build up (e.g. pine needles), and forest management practices – for example how densely the forests are allowed to grow – have been blamed as contributors to the intensity and extent of the Station Fire.

But there is no denying that with man on the scene there are fewer places a large cat or bear can move to when fire strikes (a mountain lion was spotted in my in-laws’ drive – and that was before the fire).

Ironically perhaps, this region of California is home to several man-made animal sanctuaries, the inmates of which were themselves threatened by the recent fire.

The Roar Foundation at Shambala Preserve, run by actress Tippi Hedren (of Hitchcock’s ‘Birds’ fame) went on standby to evacuate its collection of large cats – including Michael Jackson’s tigers; and most of the 400 animals at the Wildlife Waystation Sanctuary – including a sizeable collection of chimpanzees – were evacuated to Los Angeles Zoo. I’m pleased to say my gibbon friends at nearby Santa Clarita were oblivious to this incident.

Now the fire is over, scientists and economists alike are poring over the barely cooled embers to assess the full impact and inform future policy. There is still much to do, but the concensus so far seems to be that the ecosystem as far as plant-life goes will recover. The fate of the various displaced animal species is much less certain or understood.

Besides the impact of forest fires on the immediate ecosystem and its inhabitants, incidents like this put us in mind of how deforestation of all types influences the balance of greenhouse gases and global warming.

This is a huge subject in its own right, and another complicating factor to be absorbed by those nations negotiating ahead of Copenhagen. This 2007 article from ScienceDaily gives some indication of the scale of the impact, pointing to research showing how a single fire season in some North American States can generate CO2 equivalent to that State’s annual emissions from entire man-made sectors such as transport or energy. And this before a consideration of the feedback effect of rising temperatures on the frequency of fires and complications associated with the impact of smoky particulates.

All in all, a fuller analysis of this aspect – on this blog at least – is going to have wait for a future post.

Also of interest:

Sparks fly over study suggesting wild fires cut CO2 (The Guardian)

climate, conservation, environment, Politics

Kids Leave Dirty Footprints

August 13, 2009 Tim Jones Leave a comment

Want to reduce your emissions? Forget about the gas guzzler, holidaying at home, or buying local produce; cut your “carbon legacy” and have fewer children, says new research.

people

In recent weeks I’ve attended two public discussions dealing with the big-picture issues of sustainability and balancing development with conservation, and neither of them did much to allay my fears or educate me about the threats associated with population growth.

I may be joining the wrong events, but it seems all too easy to miss population off the formal agenda, or leave it to a brave audience member to raise the issue at question time – when it can be scooted over or dismissed with a glib reply. A popular counter to worries over population growth in developed countries – at home as it were – is to state that growth is mainly happening in the developing world, where per capita consumption is relatively low. For me, that seems to ignore the medium term consumption aspirations of developing countries (look at how fast China has moved) and underplays the ratio of the impact of an individual’s consumption between the developed and developing worlds. But I suspect most of us don’t really know what to think, and lack meaningful data to work it out for ourselves.

Now that position has improved somewhat, with the publishing this month of a formal analysis of these very issues by researchers from Oregon State University. Murtaugh’s and Schlax’s paper: ‘Reproduction and the carbon legacy of individuals‘ is published in the journal Global Environmental Change, and also downloadable as a pdf here. In the authors own words:

“Here we estimate the extra emissions of fossil carbon dioxide that an average individual causes when he or she chooses to have children. The summed emissions of a person’s descendants, weighted by their relatedness to him, may far exceed the lifetime emissions produced by the original parent.”

It’s more usual to work out an individual lifetime’s worth of carbon footprint. But in the Oregon study, a parent is instantly given the burden of half their child’s carbon impact, and a quarter of the carbon impact from their child’s prospective child; and so forth. When the numbers are worked through, and comparisons are made between the developed and developing world, it’s apparent that not having that extra kid is a great way to save the planet. According to the authors’ data, the impact of that decision far outweighs that of other good citizen actions – like downsizing the family car. The figures I find most provocative are the comparisons of the impact of children born in different countries. Take the USA and Bangladesh for example: I’d assumed just on a gut feeling that a US child’s carbon footprint would be 20 or 30 times that of a child born in Bangladesh. The figures in the new paper, with the children’s decendents accounted for, put the ratio at 168:1 – equivalent to average carbon emissions of 56t and 9441t for the Bangladesh and US cases respectively.

The carbon reduction figures presented for the various lifestyle changes we can make, and calculated over an 80 year period, range from 17 metric tonnes CO2 saved by recycling materials, to 148 metric tonnes by increasing automobile gas mileage from 20 to 30 mpg. Those numbers can be compared with the 9441t of emissions that could be avoided by not having an extra child.

This paper is written in the spirit of presenting data as an input for informed discussion. The authors don’t take a moral position on human rights and population control – that’s for the politicians with the people to sort out. And it’s not too far a stretch to make the analogy between this situation and that which existed when the global warming debate was put on a more data-rich, objective, footing by the issuing of the Stern Report in 2006. However the detail and assumptions in this work may be criticised, as surely they will be, it’s good to see some quantification around this complex piece of the sustainability jigsaw.

Reference:

Paul A. Murtaugh a,*, Michael G. Schlax b ‘Reproduction and the carbon legacies of individuals’, Global Environmental Change 19 (2009) 14–20

(Originally posted at conservationtoday.org)

Also of Interest

Is population growth out of control (BBC September 2013)

astronomy, biology, Chemistry, climate

Interview with an Astrobiologist

June 20, 2009 Tim Jones 1 Comment

Life on Earth and the possibility of life beyond the stars fascinates Dr Lewis Dartnell.

Is there life out there....? (Photo NASA) — Is there life out there….? (Photo NASA)

I interviewed Lewis for Imperial College Radio, and this podcast is the full conversation. We cover Dartnell’s core research in Martian radiation, the recently launched Kepler telescope, possible earth asteroid strikes. Lewis describes how knowledge of conditions on other worlds might inform maintenance of the Earth.

The noisy aircon is regrettable; and as a result the sound quality is less than ideal.

climate, conservation, education, environment

Earth Hour – Consciousness Raised? (a bit?)

March 28, 2009 Tim Jones 2 Comments

Well that’s the World Wildlife Fund’s ‘Earth Hour’ over and done with for another year.

At least that’s the cynic’s (realists?) view of this annual attempt to get the world’s lights switched off for an hour, on a rolling cycle from 8.30 – 9.30 pm, across the globe. It’s just happened in the UK.

I’ve heard the arguments for and against what some see as a ‘stunt’. I support it all the same.

Whatever else the organisers intended, events like this raise consciousness in those they touch – even if that excludes the worst offenders.

Against that is the view that one-off gestures make people feel good at the time, but that real benefit is lost in ‘business as usual’ during the year. I’ve not seen any statistics, so won’t comment; maybe the WWF have done the research?

But I can’t get excited about criticism that people might actually use more power during the ‘lights out’ hour. On balance, I hope there’s a reduction, but don’t see it as a huge deal if not. I feel guiltier when I’m using power.

Events like Earth Hour raise consciousness; an essential ingredient in any discussion on global warming, religion, famine, conservation, or any number of contentious science-related issues. The Earth Hour critics are right that you can’t force people to act, but you can nudge them in the right direction. This is a preparing of the ground, warming people up gently so they don’t melt when faced with the full real cost of energy. And rather than giving the impression that turning out lights will save the planet, Earth Hour might just spur some to follow up on the detail of the broader picture.

Next year maybe we need the ‘leave the X5 in the garage for a month stunt’, or the ‘cancel one of the two long-haul hols. stunt’? A sustainable planet will require fundamental life-style changes – to paraphrase Sir David King (again, sorry) at this year’s Darwin Day lecture: things won’t really sort themselves out until girls stop fancying blokes in Ferraris…… (go figure).

I did hugely exciting stuff in my dark hour. First, I checked out the appartment building and found the lighting pattern pretty much as I remember it from any other Saturday night (no control – my not being scientific, sad, or both, enough to photograph the place over the two previous weeks). Then to the supermarket with my re-useable plastic bag (by now I’m visibly radiating good-citizenship with my raised consciousness before me), arriving home 20 minutes early and requiring the PC be prematurely re-activated as a light source.

In that 20 minutes, I did the back-of-fag-packet calculation that a billion people (the WWF target) turning off a 100W bulb = 100,000 MW or 200 power-stations at 500MW or 100 at 1000MW. My personal saving was much less than 100W, at 22W for the 2 x 11W fluorescent lamps we run in the lounge which, as a fraction of the power used by the 300W TV and 150W PC found in most homes, supports the critics numerical case. But if you think that’s what it’s about, you’re missing the point.

Anyhow, off to phone my other half who’s in the USA at the mo’ – need to get those double Earth Hour Brownie Points.

climate, environment, events, media, Politics, science communication

“Very Little Can Stop The Train” Sir David King On Media Reporting and MMR

February 11, 2009 Tim Jones 1 Comment

I’ve just returned from the annual British Humanist Association Darwin Day Lecture, this year delivered by Sir David King at a session chaired by Richard Dawkins.

Sir David King and Professor Richard Dawkins at the BHA Darwin Day Lecture 2009 (photo Tim Jones)

King is a former Chief Scientific Advisor to the UK Government, and now heads up a multi-disciplinary organisation tackling climate change – The Smith School of Enterprise and the Environment- at Oxford University.

His talk entitled ‘Can British Science Rise to the New Challenges of the Twenty First Century?’ was very similar in content to one I watched him give at a PAWS event in November, and dealt less with British Science, and more with the complexities of tackling global climate change. There were some new angles, but I’d refer you to my previous blog HERE – inspired by Sir David’s earlier talk – rather than repeat myself. I believe a podcast of tonight’s event will appear on the BHA site in due course.

So perhaps, given the greater relevance to current debate over poor media reporting of science, and particularly that related to MMR (and the Goldacre/LBC radio encounter), you’d like to hear what Sir David volunteered tonight on that subject. It came up in response to a question from the floor about the Daily Mail. Sir David’s transposed response:

“We’ve now got a measles epidemic growing in this country, and the measles epidemic is the result directly of a very poor piece of science from John Wakefield, somehow being published in the Lancet – should never have been published – the database was far too small. And then gaining momentum in the media, and it’s not only the Daily Mail, John Humphreys was one of those pushing that… that the connection between MMR and autism raised real questions, and the take-up of the MMR vaccine began to fall very dramatically. And my prediction a few years ago was that we would approach something like a hundred deaths a year from, amongst children, from measles as a measles outbreak occured, inevitably.

If you do models and you drop below 80% uptake of the vaccine, the measles must come back. Of course the Daily Mail’s campaign was one of the instruments that got people very worried about that particular issue. So I think that was an example where the science was so clear. Let me tell you. There was a Danish study of all the children born in Denmark over ten years of whom 15% had not had the MMR vaccine, and 85% had. The statistical incidence of autism in the two groups was the same. Now just to be on the…on the…..when I say the same within statistical error. The nice thing was, from the point of view of those who were sceptics, that amongst the group who didn’t have the vaccine, there was a slight larger number- larger percentage – with autism. Now any parent worrying about the situation, just needs surely to be given that set of statistics, and yet the Daily Mail wouldn’t publish it when I went to them. What am I saying, [finding his words]well, it rarely gets their story right. There is…there is a sort of disbelief, but I’m afraid when a newspaper is running a campaign, there’s very little can stop the train”

To which Richard Dawkins, with a look of amazement and with apparent reference to the Daily Mail not printing the Denmark evidence, said – “I’m shocked”

Communicate Science