The bad news about the Black Death


Illustration of the Black Death from the Togge...
Illustration of the Black Death from the Toggenburg Bible (1411) (Photo credit: Wikipedia)

Well, the good news first: all current known strains of the Bubonic Plague causing bacterium are genetically similar to traces of the Yersinia pestis bacterium found the skeletons of Londoners who died in the 1340s – when the plague killed a third or so of the population of Europe.

That means (we hope!) there is no realistic prospect of a mass plague breakout based on existing bacterial strains – though it should also be noted that the evidence in favour of the effectiveness of current plague vaccines is limited.

But now the bad news: in the sixth century the Justinian Plague contributed to the collapse of the Western Roman Empire by killing off about one-third of the population. From the perspective of historical distance this might be seen as a good thing – the collapse of the cruel imperium – just as the historical legacy of the 1340s Black Death – the breakdown of serfdom and an acceleration of the humanist revolution might seem boons today. But we can be sure that nobody thought so at the time! And in today’s complex and interconnected societies even much smaller death rates would surely tip us over the edge. And the Y. pestis that caused the Justinian Plague has now been shown to have a different genetic makeup from the Black Death’s.

Writing in The Lancet Infectious Diseases (DOI:10.1016/S1473-3099(13)70323-2) Hendrik Poinar and others write:

We conclude that the Y pestis lineages that caused the Plague of Justinian and the Black Death 800 years later were independent emergences from rodents into human beings. These results show that rodent species worldwide represent important reservoirs for the repeated emergence of diverse lineages of Y pestis into human populations.

This is, indeed, bad news – as it means that we could be faced with a new plague breakout and have to start the war with the bacterium from scratch (think of Contagion).

The Plague of Justinian was not just one outbreak either – it kept coming back (much in the way that the plague of Black Death did not end in the 1340s – as The Diary Of Samuel Pepys demonstrates.

And if you want an extra worry about climate change here are the final two paragraphs of the paper (the ‘second’ plague is the Black Death, the ‘third’ is 19th and 20th century plague outbreaks):

Why the Y pestis lineage associated with the Plague of Justinian eventually died out is unclear. That it probably caused human epidemics for several centuries suggests
that it was well adapted to human transmission. As a
consequence, several viable explanations for its extinction
might be a scarcity of susceptible hosts (people, or rodents,
or both), insuffi cient numbers of susceptible hosts in a
background of widespread population immunity, or
mutations that arose and spread in the human genome
that conferred resistance to this particular plague strain.
The success of the lineage (or lineages) associated with the
two most recent pandemics is probably attributable partly
to human mobilisation, since increasing trade between
countries and continents is known to have moved people
and rodents with Y pestis infection around the world.
The Plague of Justinian and, indeed, the emergence of
all three plague pandemics, might be tightly linked to
climatic instability; all were preceded by periods of
exceptional rainfall and ended during periods of
climatic stability (around 700–1000 AD in the case of the
Plague of Justinian). Irrespective of the eff ect of climate,
the epidemiological pattern that we propose suggests
that several Y pestis lineages, which are currently
ecologically established in rodent foci worldwide, remain
capable of emerging and igniting epidemics of plague in
human beings, as they have repeatedly in the past.

(Here’s a summary in the New Scientist if you cannot access the Lancet.)

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Climate change is back


Climate is not weather… but it is a sign of how poorly framed the debate on climate change in Britain (and in the US) is, that it ebbs and flows with the weather.

So now climate change is gaining in respectability in Britain after the appalling weather of the last few months and politicians who oppose the scientific consensus are on the back foot (notably UKIP who, despite being presented with what would otherwise be a golden opportunity to kick the Conservatives, are all but silent).

As someone concerned to ensure that we act to minimise the damage from climate change of course I welcome this shift. But the point that weather and climate are not the same should not be forgotten.

Because otherwise when spring comes, as it will. The sceptics will quickly proclaim that the problem is over.

Polar vortices and climate change


Satellite Image Shows Entry of the Polar Vorte...
Satellite Image Shows Entry of the Polar Vortex into the Northern U.S. (Photo credit: NASA Goddard Photo and Video)

The recent cold snap in the United States was, apparently, seen by many as undermining the claims of a majority of climate scientists that human activity was gradually – but potentially catastrophically – warming the climate.

But, according to this article from the Associated Press, the most remarkable things about the cold was that it was not all that cold (merely the 55th coldest day since 1900) and that cold days appear, now, to be relatively rare (though, of course, a random element of statistical fluctuation may also have contributed to the length of the period – 17 years – since the last very cold period.)

One other thought – the cold in the US seems to have been matched by a very mild (in temperature, if not much else) winter in Western Eurasia. I still have nasturtiums – usually killed off by frosts long before now – growing in the garden. I would not go so far as to say they were thriving (the last flowers were seen in December) but they are still going…

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Weather and climate (again)


Once again Britain and Ireland are taking a battering from the Atlantic and so it seems a good time to remind ourselves that some of those who dispute the scientific consensus on climate change were, this autumn, citing the low level of hurricanes on the US East Coast as supporting evidence.

Now, they had played the game of mixing weather up with climate, not something to be encouraged. But I do think we are now entitled to remind them that what goes around, comes around – as the boot is now on the other foot, on this side of the Atlantic at least, with the UK’s Environment Secretary, Owen Pattersonnoted for his eccentric views on climate change – looking rather exposed at the moment.

What not to say about the bad weather


Reduction of flood and associated extreme weat...
Reduction of flood and associated extreme weather costs is the primary benefit of climate change mitigation. (Photo credit: Wikipedia)

The last six weeks has seen the UK hit by a number of storms and surely climate change is to blame? Well, no, you cannot say that.

Not because climate change is not to blame. But because we just cannot definitively pin down a weather event to a change in climate. (Of course, this does not bother many on the other side of the argument, but those who defend science should judge themselves by higher standards.)

But we can, if the resources are available, calculate the statistical probability that specific weather events are linked to climate effects.

This is the abstract of a 2011 paper published in Nature:

Anthropogenic greenhouse gas contribution to flood risk in England and Wales in autumn 2000

Nature 470, 382–385 (17 February 2011)
doi:10.1038/nature09762
Received: 30 March 2010
Accepted: 10 December 2010
Published online: 16 February 2011

Interest in attributing the risk of damaging weather-related events to anthropogenic climate change is increasing1. Yet climate models used to study the attribution problem typically do not resolve the weather systems associated with damaging events2 such as the UK floods of October and November 2000. Occurring during the wettest autumn in England and Wales since records began in 17663, 4, these floods damaged nearly 10,000 properties across that region, disrupted services severely, and caused insured losses estimated at £1.3 billion (refs 5, 6). Although the flooding was deemed a ‘wake-up call’ to the impacts of climate change at the time7, such claims are typically supported only by general thermodynamic arguments that suggest increased extreme precipitation under global warming, but fail8, 9 to account fully for the complex hydrometeorology4, 10 associated with flooding. Here we present a multi-step, physically based ‘probabilistic event attribution’ framework showing that it is very likely that global anthropogenic greenhouse gas emissions substantially increased the risk of flood occurrence in England and Wales in autumn 2000. Using publicly volunteered distributed computing11, 12, we generate several thousand seasonal-forecast-resolution climate model simulations of autumn 2000 weather, both under realistic conditions, and under conditions as they might have been had these greenhouse gas emissions and the resulting large-scale warming never occurred. Results are fed into a precipitation-runoff model that is used to simulate severe daily river runoff events in England and Wales (proxy indicators of flood events). The precise magnitude of the anthropogenic contribution remains uncertain, but in nine out of ten cases our model results indicate that twentieth-century anthropogenic greenhouse gas emissions increased the risk of floods occurring in England and Wales in autumn 2000 by more than 20%, and in two out of three cases by more than 90%.

At the time of those floods I was a special adviser to Paul Murphy, the Secretary of State for Wales, and accompanied him when he visited stricken areas of North Wales. It would be an exaggeration to say we saw Biblical levels of distress and destruction, but  they were unlike anything I had seen at first hand.

As the abstract makes clear the paper certainly does not say “floods were caused by climate change” – indeed it goes so far as to say that “observed UK fluvial-flood and high-flow trends for recent decades suggest no clear evidence for any change above that of natural variability17, 18, mirroring the mixed picture in observed precipitation changes19, 20.”

And, moreover, the authors state that the risk of some flooding events may actually be reduced by the factors they say increased the flooding risk from heavy rainfall: climate change is complex, something else those who oppose the science that underlies it are often unwilling to concede as they focus on populist arguments about this week’s weather or short-term trends.

The computing for the project was organised through http://climateprediction.net .

You can read more about all of this in a news item on Nature’s website.

Another example of “Delingpole-ism”


Picture of Daniel Hannan at a conference in th...
Picture of Daniel Hannan at a conference in the Grosvenor House hotel in London (Photo credit: Wikipedia)

Yesterday I highlighted the attack made on the BBC’s science reporting by James Delingpole, a novelist, English Lit graduate and – as I argued – under-qualified crank.

Delingpole claimed that the BBC should be “impartial” on science – by which he meant it should give an equal weighting to the views of the tiny minority of scientists who dispute the fundamentals of the consensus on climate change. This is a ridiculous position to take when reporting science qua science – as it would, as I suggested as an example, require us to have given equal billing to the theory of “Supersymmetry” even as the evidence to support the “Standard Model” piled up.

To argue in this way is to treat science as though it were just politics by another means. It is not.

I would not normally write about economics here but the case I am about to highlight is such an egregious example of “Delingpole-ism” that it deserves the maximum publicity.

In one corner stands Daniel Hannan MEP, who claims that the UK is “the fourth largest exporter”. Except it is not.

Pointing out Mr Hannon’s error – the UK is the sixth largest exporter or (arguably, given the fuzziness of the data) equal fifth – does not lead to a correction but instead to a torrent of ad hominem abuse towards the respected economist, Jonathan Portes, who challenged Hannan’s factual inexactitude, and a rather childish rant about how nasty the BBC are to poor people like Hannan.

As Portes states, Hannan (and I think Delingpole), are members of a form of “celebrity culture” that gives them the confidence to make ridiculous, fact-free or fact-ignoring, statements about subjects in which they have no legitimate locus and then to claim they are victims of a powerful liberal/Marxist/establishment conspiracy when someone points out they are talking out of their hat.

Mail on Sunday 92% wrong on climate change


GlobwarmNH
GlobwarmNH (Photo credit: Wikipedia)

Sadly, I increasingly fear, in future decades our children and their children are likely to look back on this second decade of the twenty-first century as a wasted opportunity to put the findings of science into action.

The scientific consensus on climate change is clear and stable. The only “argument” is about just how rapidly the threat is growing. Yet that argument – in fact often just a refinement of figures based on better measurements and more refined models – is being used to claim that the science is not agreed and that, somehow, it is legitimate to claim that climate change denial is good science.

The latest example has been the misreporting and misrepresentation of the leaking findings of a draft report from the Intergovernmental Panel on Climate Change (IPCC).

First of all – leaked findings of draft reports are not generally to be regarded as scientific reports – science does not work that way. Papers are reviewed and finalised for good reasons.

Secondly, misreporting renders even your attempts to manipulate such leaked draft reports as little better than chip paper.

And that is just what the Mail on Sunday – one of the leading engines of the science-denial brigade in the UK – have been caught doing.

As this excellent blog shows – the Mail on Sunday claimed that scientists were about to reduce their estimate of the long-term warming by 50% when, in fact, the reduction was about 8% (or one one-hundredth of a kelvin).

Such journalism – personally I think this sort of reportage belongs in a comic, not a serious national newspaper – poisons public debate all too often. And, without wanting to comment on the individual views of the journalist concerned here – one David Rose – it is plain there is a determined attempt by some to have ideology trump science. That cannot be allowed to stand.