…and it’s not a director’s cut of David Attenborough

According to a Nature paper that’s receiving some pickup (Reuters, CSM ) the history of life on earth may just have got roughly 15% longer. That may not sound a huge difference, but a 15% extension on life’s lease adds up to 600 million years — roughly equivalent to the time taken for animals to get from creepy little things that couldn’t even crawl to your pet cat.

There were no animals on earth, though, during the 600 million years in question. The paper by Oleg Abramov and Stephen Mojzsis [link fixed] at the University of Colorado is about the earliest life, not the latest. Previous research has suggested that the heavy rain of asteroids, comets and the like that characterised the early solar system would have made the earth too hazardous a place for life to persist until after what is known as the “Late Heavy Bombardment” some 3.9 billion years ago. Impacts by large objects, it was thought, would vapourise whole oceans and wrap the earth in an atmosphere of superheated steam which would sterilise the planet.

The model developed by Abramov and Mojzis tells a different story. Pretty much everywhere on the planet gets zapped by a big rock, often more than once – but there are never any occasions where the whole planet including all the subsurface is simultaneously uninhabitable. If life had got started during this time, they argue, it could have persisted ever since.

At present the first evidence for life comes right after the Late Heavy Bombardment, about 3.8 million billion years ago. The speed with which that life developed after the bombardment has been seen by some as evidence that life is implicit in the way the universe is set up, and will arise spontaneously PDQ wherever it gets the chance. If it took 600 million years, though, then one would have to start thinking that life is relatively unlikely, which obvioulsy has implications for astrobiology.

It may still be the case that life arose as soon as it could, right at the beginning of the earth’s history – but it is going to be harder to prove it. While bacteria may have been able to survive the horrible early history of the earth, rocks were not so lucky – there are no major bits of crust left over from back then.

In a related happy accident, this week Nature also has a fine feature on Mike Russell and his research on the metabolism-first approach to the origins of life.

Image: simulation of the state of the Earth at the end of Late Heavy Bombardment. Circles are crater locations; colors show temperature / Oleg Abramov

Cross posted from Heliophage

Interest in biochar has been building up in the UK recently. There was a cover story by Fiona Harvey in the FT a month ago with a familiar headline, Jim Lovelock and James Hansen have been extolling its virtues, it’s been on the Today Programme (text here on BBC News), there are new technologies being talked up and there’s an interesting looking workshop at the newly established UK Biochar Research Centre in Edinburgh on April 1st. And so of course there is also a backlash: last Monday George Monbiot, whose written on such subjects before, delivered a stirring oppositional salvo in the Guardian (and here’s the link to the version on his own site, same text but with references — a good habit more newspaper columnists should take up):

This miracle solution has suckered people who ought to know better, including the earth systems scientist James Lovelock(3), the eminent climate scientist Jim Hansen(4), the author Chris Goodall and the climate campaigner Tim Flannery(5). At the UN climate negotiations beginning in Bonn on Sunday, several national governments will demand that biochar is eligible for carbon credits, providing the financial stimulus required to turn this into a global industry(6). Their proposal boils down to this: we must destroy the biosphere in order to save it.

In his otherwise excellent book, Ten Technologies to Save the Planet, Chris Goodall abandons his usual scepticism and proposes that we turn 200 million hectares of “forests, savannah and croplands” into biochar plantations. Thus we would increase carbon uptake, by grubbing up “wooded areas containing slow-growing trees” (that is, natural forest) and planting “faster-growing species”(7). This is environmentalism?

…

Read the rest of the post — more Monbiot and responses to his criticism — at Heliophage —>

A sobering presentation by Marshall Burke of Stanford on future agriculture. He and colleagues looked at historical climate and yield data for various crops in various parts of the world and projected the relationship they found into various future climates as found in the IPCC. As the IPCC itself reported, much of the tropics did badly in this analysis, and the worst performer was maize in southern Africa which was down in yield by about 30% by 2030.

More granular data run out to 2050 showed similar or worse trends, and the rest of Africa did pretty badly too. So did other crops in the same countries, such as millet and sorghum, though as Andy Jarvis of Biodiversity International pointed out from the floor, this may be somewhat worst case. You don’t just go on growing the same thing as the situation gets worse and worse. As climates change so will the crops farmers grow, which should help a bit.

While the IPCC has already predicted that tropical agriculture will have its productivity hit by any climate change, it said it expected that in temperate zones modest warming might help productivity. In at least one case Burke went into — maize in the US — there are studies suggesting things start going wrong much sooner than that, with yield losses of 30% or so by 2030. Modest rises have been seen: sharp downturns are to come. Burke says that an economic model fed with these and other gloomier-than-common yield assumptions suggests that prices are set to rise more steeply than the IPCC has foreseen: a 1ºC rise in temperature looks like a 25% increase in prices, hurting some poor farmers and a lot of poor consumers.

As Burke pointed out, we care about these food security issues because we care about people. A World Bank study suggests that the food crisis of 2007-2008 pushed 100m people into poverty. Reduced yields are normally bad for poor farmers, for whom consequent price increases rarely make up for lost production. They are also bad for the urban poor, who just see the price increases. That 25% increase in prices will some poor farmers and a lot of poor consumers. And on current trends that’s just the beginning.

I had a look this morning at a breakdown of the press registration at this conference by country. Clear winners are Denmark and the UK, with 40 or so people each. Both of those are inflated figures, because some third-country and international organisations are covering the meeting out of Copenhagen and London (Japanese TV stations are listed as UK, for example, as is Al Jazeera English). But still there is a lot of genuine UK interest: national papers and the BBC. And the locals are out in force.

US representation, on the other hand, seems distinctly on the modest side. As far as I can see from the press room and by searching the papers’ web sites there’s no-one here from national papers (the Paris-based International Herald Tribune is a sort-of-exception) and not much broadcast. Time is listed as a media partner, but I haven’t seen Bryan Walsh here. The rest of the world is represented at a pretty low level, but still here — I was struck by a biggish contingent from Bangladesh.

Does it matter? Hard to say. The conference is hitting headlines, there are a lot of journalists for specialised outlets here, and the press room people say they are very happy with the level of coverage: Stefan Rahmstorf’s sea-level talk on Tuesday, which I didn’t see but which people here are talking about a lot, is getting a lot of pick up, to judge by Google News. But in the plenaries this morning John Schellnhuber and Nick Stern were reminding the thousand or so people in the room that this is one of the biggest stories in the world, and they were doing so pretty effectively. And part of the point of this meeting, as I understand it, is to take that same sort of approach and use it to set a scientific stage for the COP 15 “son of Kyoto” meeting, which will take place in the same large shed-like structure this December. By that standard, the coverage that I have seen (and I’ve been busy, to be fair, just talking to people at sessions, and may have missed lots of good stuff) seems a little thin.

It appears that the action on Wednesday afternoon was where I was not: in the session on tipping points. Chris Jones of the Met Office’s Hadley Centre presented some studies of the Amazon (abstract in pdf) that have caused a big media stir. The studies suggest that a) there is a threshold level of warming beyond which much of the Amazon forest is committed to die back (probably being replaced by savanna) and b) that for significant parts of the forest that threshold is alarmingly low. Indeed it is quite possibly either unavoidable in the near future or already dwindling in the rear-view mirror. As I understand it from people who saw the presentation, models in which all the warming already in the pipeline (ie with no further emissions) is realised leave the forests pretty much committed to some dieback, and modest further warming seals the deal. I wasn’t able to check that with Jones himself, but it seems to fit with what he and his colleagues write:

We present results to show a possible climate threshold beyond which some dieback is committed and this commitment rises dramatically for global temperature rise above 2 degrees C, a threshold often used by policy makers in their definition of dangerous climate change. Any subsequent recovery is on such a long timescale as to make the dieback effectively irreversible on any pragmatic level.

Here’s the coverage from the Times and here’s some from The Guardian. Worth noting that it’s a single study, that there are error bars to consider and that people have in the past suggested that the Amazon is often more vulnerable in the Hadley Centre model than in most others. But still very worrying; all the more so if it were to be spun as a counsel of despair on efforts to stop deforestation on the basis that there’s no point preserving a forest that’s already doomed.

I’ll see if I can find Chris Jones, or some Brazilians, or both to talk about this with on Thursday.

Cross-posted from Heliophage

For those not eager to trawl through the aforementioned geoengineering tweetstream here’s the most interesting thing I took from the geoengineering session — a point on which, interestingly, David Keith and Ken Caldeira, who are keen to see and do more research on the topic, are close to agreeing with David Santillo of Greenpeace, who isn’t.

The problem is in some ways pretty obvious: No one knows whether geoengineering can really be made to work. As Keith pointed out, even for the best characterised putative intervention — a stratospheric aerosol like those produced by volcanoes — the comparatively cursory research to date has turned up a wealth of complexities that have not yet been addressed by proponents, and more research will turn up even more of them. To Keith and Caldeira, this raises a nightmare scenario: that the world will have in the back of its mind that geoengineering is there as a fallback, will find that it needs a fallback, and will then find out that the fallback is not there in any practical sense. On this basis the sooner it is clear that there is no way out the better: time to do some serious research.

That is similar to Santillo’s position, except he doesn’t want to do the research needed to find out for sure. I took it from his talk that he wants instead to create a climate of opinion where the nagging hope that geoengineering might save us was firmly shut down more or less a priori, with commitment to emission cuts the sole and reaffirmed goal of all.

In making this argument, he came up with a nice pithy account of what he sees as the 5 drivers for geoengineering research: desperation, aspiration, fascination, delegation, remuneration. The first two he sees as essentially reasonable, the third — “it is just such fun to play with these ideas!” — troubling, the fourth — “O good, someone else can solve the climate I don’t have to” — dangerous and morally defective (my term not his), and the fifth beyond the pale. (Actually in the presentation he didn’t call the fifth driver “remuneration” he just called it “money” — but he told me later he’d thought about listing it as remuneration, and I think it’s slicker that way…)

What all these people agree on is that the lopsided way in which geoengineering is discussed, with a level of prominence in the media (and the unpublished musings of researchers, in my experience) and the imagination disproportionate to the actual level of knowledge among experts, needs to be seen as a real problem. Geoengineering is widely enough discussed that the thought it might be there as a last resort is widespread and quite possibly spreading wider, even though it still may be an illusion. Keith laid out the argument for reducing this disproportionality in a more formal way, looking at scenarios comparing the value of “Early Learning” v. late learning. I didn’t note down all the details, but Early Learning seemed, by the economic metric he was using, to be a big, big winner.

PS: Those interested in the twittering per se may possibly want to check out this further post at Heliophage

There’s a technical session on geoengineering at the meeting today, and I thought I’d try twittering from it. Since this is a personal experiment and may not pan out, I’ll be using my personal twitterfeed, https://twitter.com/eaterofsun, not the naturenews feed.

Like Olive, I’m at the Climate Change Congress in Copenhagen. My first impression is that it’s like a scaled up version of the Avoiding Dangerous Climate Change meeting that took place in Exeter in 2004: a venue for up-to-date (ie more recent than the most recent IPCC) science to be presented in a polciy relevant atmosphere. And by odd coincidence the first paper I heard presented was on a topic that in my mind is quite strongly linked to that Exeter meeting.

Jonathan Bamber of Bristol University was talking about the stability of the Greenland ice sheet at a session on tipping points. There was a widely cited Brief Communication in Nature that came out just after the Exeter meeting and was discussed there which suggested that if global temperatures rose above 3 degrees the ice sheet was effectively doomed. Bamber and his colleagues have looked at the issue again, treating the point at which the surface mass balance goes negative as the defintive oops-we-lost-Greenland point. Surface mass balance is snowfall minus the run offs. Even with a positive surface mass balance it’s possible for the ice sheet to shrink, because ice is lost through the calving of icebergs as well as runoff; once the surface mass balance goes negative, though, shrinkage is taken to be certain and to feed on itself.

Bamber says he and his colleagues looked at the future of the ice sheet in a warming world using two different types of mass balance model: a positive-degree-day model, which counts days over freezing, as was used in the earlier work, and a more complex energy balance model. Their positive-degree-day model showed the mass balance going negative with four degrees of warming locally, which because warming in the arctic is amplified beyond the global mean fits with the earlier figure of 3 degrees warming worldwide. The energy balance model, though, doesn’t see the mass balance go negative until there’s 8 degrees of warming. Bamber’s clear that there’s a lot of uncertainty in that — but it fits with the palaeoclimate finding that in the previous interglacial period, when temperatures were higher than they are now, significant chunks of the Greenland ice sheet remained un-melted.

On the face of it that’s a bit of a reprieve: it would seem to suggest that there’s more time to act before the world gets committed to a big, big sea level rise than had been thought. But there are lots of caveats. Ice dynamics or some other factor could mean that there’s a point of no return before the point at which the mass balance goes negative. And though this model may be better than the previous one (and there may well be people who would doubt that) that doesn’t make it definitive. You can look at the best science around — but there’s always going to be doubt as to whether its good enough.

If you really want to go down the “technological fix” route with respect to climate change, which proposed schemes for cooling the planet offer the most bang? A new study by Tim Lenton and Naomi Vaughan at the University of East Anglia seeks to answer that question by looking at the various options on offer in terms of pure energy — how many watts per square metre of warming can they counteract?

Caveat: this is a study of bang pure and simple, not bang-per-buck and not oh-dear-that-bang-seems-to-have-blown-my-hand-off. Arguments against the various proposals will be the subject of another forthcoming paper. That said, the main take home message from this study is that schemes which evenly weaken the sunlight over the whole planet, either with particles in the stratosphere or spacecraft in orbit, are the winners. Brightening clouds has some serious potential, too, as do truly massive forestry schemes; but ocean-fertilisation techniques, of which a variety have been discussed, are largely ineffectual (which is to say they deal with only about 10% of the forcing due to greenhouse gases already in the atmosphere, to say nothing of those as yet to be added). Burying biochar, as recently recommended by Lenton’s mentor Jim Lovelock, isn’t that much better (though it has other benefits too).

More detail in a longer post over at Climate Feedback. Or if you want to go elsewhere the story is covered by the Eastern Daily Press (local paper for the University of East Anglia) and the Natural Environment Research Council’s web site. The wires have it too (AFP|Press Association|Reuters)

Cross-posted from Heliophage

A very useful paper (abstract|pdf|discussion space) comes out today in Atmospheric Chemistry and Physics by Tim Lenton and his student Naomi Vaughan. Tim told me when I was reporting the Andy Ridgwell paper on leaf albedo (Nature story|blog entry) that he’d become pretty interested in evaluating geoengineering schemes, and was setting up a group at the University of East Anglia to assess them. This paper presumably represents the first fruits of that interest, providing a ranking of most of the geoengineering schemes proposed in the literature in terms of the amount of radiative forcing they can provide.

Radiative forcing is, more or less, the difference in terms of energy per square metre that’s associated with any given action that changes the climate; it’s a pretty routine way of expressing things in IPCC-land. The IPCC puts the radiative forcing associated with the greenhouse gas industrial and industrialising societies pumped into the atmosphere from 1800 to 2005 at about 1.6W/m², and the forcing for a doubling of CO2 at about 3.7W/m².

Lenton and Vaughan first divide geoengineering proposals into two sorts: shortwave and longwave. Shortwave schemes seek to reduce the amount of energy that gets into the earth system by reflecting away incoming sunlight. Longwave schemes seek to increase the amount of energy leaving the earth system by making the atmosphere more transparent to outgoing infrared radiation — that is, by reducing the greenhouse effect. Then they assess the two with some very simple modelling (well, for the longwave there are some wrinkles, but it’s all in principle pretty simple). They don’t claim that the figures they come up with are the best available in any particular case, just that they are all derived the same way, and so allow fairly straightforward comparisons. By standardising the techniques they also show up a few errors in previous analyses: for example, if you increase the total amount of light reflected back into space by clouds, you reduce the amount reflected by the surface, simply because less light gets there in the first place.

The first and most striking conclusion is that if you want to have a big effect, go shortwave. Sulphate aerosols in the stratosphere (which were the main topic of this piece and these Climate Feedback posts) and mirrors/refractors in space (also in that piece, and in this paper by Roger Angel) both have the potential to provide as much by way of negative forcing as a doubling of CO2 provides by way of positive forcing. Not surprising; if you’re not constrained by money or by concerns about environmental side effects, you can put mirrors in the sky and particles in the stratosphere until it’s darkness at noon.

When you leave these global technologies behind, the other shortwave interventions rank, unsurprisingly, more or less according to the area they affect. Increasing the brightness of marine stratocumulus clouds, as proposed by John Latham, would affect about 17% of the earth’s surface, and the Lenton-Vaughan analysis suggests that the whitening effect would have to be considerably more marked than previous work has assumed; but if that brightening could be achieved then a negative forcing that averages more than 3W/m² should be possible. Covering non-sandy deserts with aluminium and polyethylene (not an idea I had come across before, and a pretty silly one as far as I can see: more here if you want it) makes 2% of the surface a lot brighter, and gets you an average 1.7W/m² of negative forcing, obviously very unevenly spread. Increasing the brightness of the planet’s grassland as Robert Hamwey has discussed (pdf) gets you 0.64W/m², and the Ridgwell et al idea of planting brighter crops gets you 0.44W/m² at best, croplands being smaller than grasslands. Lightening everywhere that people actually live (another idea from the Hamwey paper) gets you 0.19W/m²; increasing the area of plankton blooms that seed the creation of clouds in parts of the southern ocean gives you just 0.016W/m² (and that may be an overestimate) and restricting yourself to just creating shinier cities gives you no more than 0.01W/m².

What of the longwave?

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