Monthly Archives: January 2010

Same old Bolt, same old story.

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wilson-boltUpdate: Andrew is at it again.  Either he doesn’t understand the science or he is wilfully distorting the information surrounding the impact of climate change on coral reefs.

See also this posting and this one on huge impacts of exceptionally warm water in Western Australia on coral reefs.

Update: this piece was first published back on Feb 10th, 2009 – I thought it would be worth bringing up to the top to highlight Bolt’s ongoing war against science.

After last nights airing of the Australian Story (click here if you missed the epsiode), the columnist Andrew Bolt has decided to play the wounded soldier, accusing ABC Australian Story of bias.  Like me, you might find this a little amusing coming from someone who spends most of his time spinning the truth on all number of issues at the expense of his unable-to-respond victims.  Apart from failing to tell you that the ABC went to great lengths to put up the full video of our exchange (which is up on their website here, and the fact that he got the last word), he continues to accuse the ABC of bias and scientists like me of being eco-alarmists.  In a very tiresome way he has trotted out the same old accusations despite the fact that he has been corrected endlessly.  So much for his adherence to the truth!

Anyway, here we go again:

Accusation 1.  “In 1999, Ove warned that the Great Barrier Reef was under pressure from global warming, and much of it had turned white. In fact, he later admitted the reef had made a “surprising” recovery.”

Firstly, Andrew has the year wrong – I think he meant 1998.  In 1998, 60% of the Great Barrier Reef bleached, and about 5-10% of the reef died. These are not my figures, but figures from the surveys done by the Great Barrier Reef Marine Park Authority. All published in peer review journals rather than newspapers.  Secondly, it is true we as a scientific community were very concerned – rightfully so given similar events happened in the Western Indian Ocean in 1998, which resulted in 46% of coral reefs being destroyed.  One third of those coral reefs destroyed remain missing in action, and have failed to recover 10 years after the event.   Third, in all of Andrew’s comments so far, it is apparent that he fails to realise that we were talking about the risk of particular events happening.  As waters heat and corals bleached, there is the increased risk of reefs like the Great Barrier Reef being severely damaged.  I believe that it would be remiss of scientists not to communicate the concern about this increased risk – I challenge anyone who thinks that this is an alarmist strategy.

As for my comment about a “surprising recovery” – like many reef scientists, I was overjoyed to see that the Great Barrier Reef had fared better than the Western Indian Ocean. The fact that the risk had increased sharply but we got away with only 5-10% of the reefs being damaged was good to see.  Despite the small percentage though, 5-10% of reefs represents about 4,000 square kilometres of coral reef being destroyed.  That is, even though it wasn’t as bad as the catastrophe in the Western Indian Ocean, it was still a highly significant event.

Accusation 2. “In 2006, he warned high temperatures meant “between 30 and 40 per cent of coral on Queensland’s great Barrier Reef could die within a month”. In fact, he later admitted this bleaching had “a minimal impact”.

I stand by the statement that coral bleaching is a serious threat to the Great Barrier Reef – to date we have gotten off lightly compared to other areas around the world. Let’s examine what actually happened in 2006.  Early in that year, we saw an unusual and rapid warming of the waters of the Great Barrier Reef and the risk of a major bleaching event escalated as temperatures climbed. Leading scientists from the Great Barrier Reef Marine Park Authority were saying exactly what I was saying. Both US experts at NOAA and NASA came out with similar statements.  While the northern Great Barrier Reef looked like it might be damaged, the risk dissipated as summer progressed.  As it turned out, however, the hot water remained in the southern Great Barrier Reef and killed 30-40% of corals in that region. Again, the outcome was not trivial but it wasn’t as bad as the sorts of catastrophes we had seen in other reef regions around the world, such as the Caribbean and Indian Ocean regions.

Accusation 3. “In 2007, he warned that temperature changes of the kind caused by global warming were again bleaching the reef. In fact, the Global Coral Reef Monitoring Network in December said there had been no big damage to the reef caused by climate change in the four years since its last report, and veteran diver Ben Cropp said that in 50 years he’d seen none at all.”

Putting Andrew unsubstantiated quotes aside, there are some huge inaccuracies and problems in this missive.  Firstly, Andrew’s claim that the Global Coral Reef Monitoring Network held this position has been disputed by one of the key scientists from the network.  Secondly, referring to the opinion of a veteran spearfisherman is fine, but runs counter to the objective analysis of the evidence on this issue. I have asked Andrew to read the paper by John Bruno and Liz Selig (both leading international coral reef scientists) who have examined 6000 separate studies done over the last 40 years, and have found evidence that coral reefs both on the Great Barrier Reef and in the Western Pacific deteriorating at the rate of 1-2% per year.  The challenge to Andrew is to show why this analysis of 6000 separate studies is wrong and why he and a few unpublished ‘experts’ are right – the paper is free online for anyone to read.

Afterall, in his own words Andrew admits:

“I am not a scientist, and cannot have an informed opinion on your research.”

Then, what are you really saying?

More on the IPCC process

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A few days ago a journalist from one of the major British newspapers contacted me for my opinion on the IPCC review process, and I thought that i’d post my response here for a bit of clarity:

1.      Do you have concerns about science, data or claims presented in the final draft of the IPCC AR4 report? If so, please detail.

I do not have any major concerns except to point out that the IPCC AR4 is probably a little behind the latest science due to its careful review process and it requires the consensus of the wide array of experts involved.   The other major reason for saying this lies in the fact that the assessment reports of the IPCC are only published every 5 years or so.  The science of climate change is continuously and rapidly changing, hence reports get out of date very quickly.

Perhaps the best example of the fact that the IPCC is conservative in its predictions with the fact that AR4 failed to predict the sudden and precipitous drop of the Arctic summer sea ice.  This was not the fault of the highly qualified scientists involved, but a consequence of the fact that predictions like this are often highly controversial and, despite being true, require greater scientific investigation before all members of the IPCC expert teams involved are willing to sign on to them.  Hence, the IPCC process is an inherently conservative one, which has enormous significance to our understanding of the risk of a rapidly changing climate.

2.      Clearly the recent revelations and apology have dented public confidence in the IPCC’s process, what can the IPCC do to restore confidence in its findings for future reports?

Whereas the recent cherry-picking by a well supported denialist movement may have dented the public’s confidence in the IPCC process, the scientific community still stands behind the IPCC process.   I think that it would be very useful for journalists such as yourself to outline the process of coming to a conclusion on both sides of the debate.  On one side, you have well supported consensus science while on the other, you have non-peer-reviewed conclusions, bias and conjecture. Personally, if the public did actually see this, I don’t think they would be so much confusion.

One of the last points that make in response to your question, is that the IPCC is continuously reviewing the way that it goes about its processes.  This is a good strategy, whether you are making aircraft, manufacturing kitchen equipment or reviewing the latest science from the IPCC.  In the next few months, there are a number of documents that will be released from the IPCC (the result of review committees since AR4) that will recommend improvements to the IPCC process as we move towards AR5.  Clearly an organisation that is serious about quality and excellence undergoes such adaptive self improving reviews and procedures on a regular basis – the result being consistent with the IPCC’s mission statement of transparency, objectivity and honesty in reporting the latest science.

3.      Do you still have confidence in the chair and vice-chairs of the IPCC or should they stand down from their positions? Please also give a short explanation for your answer?

Personally, I have the utmost confidence in Dr Rajendra Pachauri and the IPCC vice chairs.  The sustained attack by the denialist movement have done nothing to demonstrate that Dr. Pachauri or the vice chairs have not fulfilled their IPCC duties to a high level of excellence. Attempts to undermine a couple of statements within the AR4 of the IPCC do not constitute reasons for not taking the other 99.99% of the carefully reviewed and supported science extremely seriously.

Perhaps it is useful to look at the standards on the other side of the ‘debate’.  The recent book by the denialist Ian Plimer from the University of Adelaide (“Heaven and Earth) had so many errors and falsely supported references that one university professor commented that the book would fail outright if it had been submitted as a Ph.D. thesis.

4.       Should the AR4 be reviewed in detail to check for other errors, particularly given that it is a document designed to help governments and officials make policy decisions that can impact both the environment and on people’s lives?

It is important to already realise that the IPCC is already a review document – its role already is to bring together the conclusions of thousands of scientific studies.  It also has a clear and transparent process and a excellent track record of reporting the latest scientific consensus accurately (see above).  This is unparalleled by any other source of information (compare it to the convicted felon and chief scientist Jay Lehr of the Heartland Institute for example).   In my opinion, as someone who knows the IPCC process and its outputs well, I don’t think a detailed review would find more than vanishingly small number of poorly supported or erroneous statements, among thousands of scientific statements that are robustly supported.

However, given the extreme importance of climate change to government decision-making, it would be important in my opinion for any government or decision-making body using the IPCC process to apply due diligence – to explore it and be satisfied with its accuracy, objectivity and thoroughness.

More hot air from Andrew Bolt over the IPCC

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I see that Andrew Bolt is spearheading another baseless anti-IPCC rant over on his blog. Unsurprisingly, it’s another non-issue – involving the IPCC referencing reports by Greenpeace. Same old Bolt, same old story – click here to read just how wrong Andrew has been in the past. Instead of going for the science (after all, in our last debate, Andrew conceded “I am not a scientist, and cannot have an informed opinion on your research”), Bolt specifically takes a swipe at the inclusion of a report I authored back in 2000:

Considered the climate Bible by governments around the world, the UN’s Intergovernmental Panel on Climate Change (IPCC) report is meant to be a scientific analysis of the most authoritative research.

Instead, it references literature generated by Greenpeace – an organization known more for headline-grabbing publicity stunts than sober-minded analysis. (Eight IPCC-cited Greenpeace publications are listed at the bottom of this post.)

In one section of this Nobel-winning report, climate change is linked to coral reef degradation. The sole source for this claim? A Greenpeace report titled “Pacific in Peril” (see Hoegh-Guldberg below).

This is the offending report – please feel free to read through and comment below.

Hoegh-Guldberg, O., H. Hoegh-Guldberg, H. Cesar and A. Timmerman, 2000: Pacific in peril: biological, economic and social impacts of climate change on Pacific coral reefs. Greenpeace, 72 pp. (link to PDF here)

Ignoring the blatant threats to myself and other scientists on Bolt’s blog, one of the most valuable comments in the entire thread is from a commentor, Eldon Degraw:

“What the IPCC reports have been shown to have is a consensus scientists, plus the consensus of WWF and Greenpeace activists, Guardian journalists and other non-scientists, submitting work that isn’t peer reviewed at all.

So, instead of showing a consensus of scientists in the IPCC reports, we have a ‘consensus of some people involved with the matter’. ”

You mean ‘a consensus of scientists plus other people involved in the matter’. I hardly expect climate scientists to be experts on areas outside of climate science (such as economic effects of coral reef degradation on Pacific cities). In fact the Greenpeace study you’re dismissing wasn’t being cited for scientific claims, only for the claims about likely economic impacts. I don’t see a problem. And the ‘Greenpeace Activists’ who wrote it were actually biologists (Ove Hoegh-Guldberg, for instance) whose other papers in peer-reviewed journals (Science, Nature) were used as references for scientific claims regarding the causes and current state of coral reef degradation. I don’t see your problem.

I also vote for changing the statement ‘consensus of climate scientists’. I think it should be ‘consensus of climate scientists…and more’.

Cold water coral bleaching in the Florida Keys

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According to a report from the Nature Conservancy, the coral reefs are suffering this winter in the Florida Keys following a cold snap:

Sustained cold water temperatures in South Florida and the Florida Keys triggered severe coral bleaching and even coral death, alerting resource managers and prompting a coordinated assessment response from the science community. Temperatures in some nearshore areas of the Florida Keys National Marine Sanctuary dropped to 52 degrees Fahrenheit for several days — well below average for this time of year — with fatal results for some corals.

A cold-water bleaching and die-off hasn’t occurred in Florida since the late 1970s.

“The Keys have not seen a cold-water bleaching event like this since the winter of 1977-78, when acres of staghorn coral perished,” said Dr. Billy Causey, southeast regional director of NOAA’s Office of National Marine Sanctuaries. “But today we are better prepared to document and assess the impacts of stress thanks to numerous partners.” Causey has lived and worked in the Keys since 1971.

On Coral List, Lew Gramer from the NOAA Atlantic Oceanographic and Meteorological Laboratory suggests that the cold snap might have lasting impacts:

Recent reports have surfaced among scientists, resource managers, and the media of large-scale, multi-species fish kills that have been primarily limited to shallow-water environments in Florida and Biscayne Bay.

Coral mortality has been reported from south Florida when water temperatures previously declined to 14 degrees Celsius, or below. While temperatures on offshore reef environments have been > 17-18 deg C (likely due to oceanic influence from the Florida Current), shallow-water and nearshore environments have fallen well below 14 deg C (e.g., 10-11 deg C near Long Key). It is expected that there will be some cold-water bleaching and potential for mortality in shallow-water corals and other reef organisms.

Tom Opishinski from Interactive Oceanographics posted a followup:

Our station at the Smithsonian Marine Lab in Ft. Pierce recorded a low of ~9.25 deg C in the IRL on 1/11.  A bit away from the corals but the record nicely shows the cooling trend corresponding to a 10 deg C drop occurring over a 2 week period.  Data can be accessed/viewed at http://nmnhmp.riocean.com/fp_raw.php – the plot will default to show water temperature then select “2 weeks” for the time period.

“Climate scientists are losing the fight with the sceptics”

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I thought this was worth posting (via ABC News): Professor Andy Pitman (lead author on the IPCC’s 2001 and 2007 reports and co-director of the Climate Change Research Centre at the University of New South Wales) thoughts on the ongoing efforts of climate denialists to derail the IPCC:

“Climate scientists are losing the fight with the sceptics”

“The sceptics are so well funded, so well organised. “They have nothing else to do. They don’t have day jobs so they can put all their efforts into misinforming and miscommunicating climate science to the general public, whereas the climate scientists have day jobs and [managing publicity] actually isn’t one of them.

“All of the efforts you do in an IPCC report is done out of hours, voluntarily, for no funding and no pay, whereas the sceptics are being funded to put out full-scale misinformation campaigns and are doing a damn good job, I think.

“They are doing a superb job at misinforming and miscommunicating the general public, state and federal governments.”

And he says if scientists lose the climate change debate, it would be “potentially catastrophic”.

“If this was academic debate over some trivial issue [it wouldn’t matter],” he said.

“But this isn’t. This is absolutely a fundamental problem for the Earth that we desperately needed full-scale international action on a decade ago.

“We are now 10 years too late to stop some of the major impacts that we will see and have seen as a consequence of global warming. It is not a future problem, it is a problem here today, around us.”

Professor Pitman has accused sceptics of failing to base their arguments on the facts.

“Most of the climate sceptics, particularly those that are wandering around publicly at the moment, don’t base their arguments on science,” he said.

“They have probably never read the Intergovernmental Panel on Climate Change report; they aren’t writing papers in peer-reviewed literature.

“They don’t update their arguments when their arguments are shown to be false, so they’ll have no problem at all using this ammunition inappropriately and out of context to further their aims in exactly the same way as people did when they were trying to disprove the relationship between smoking and human health.

Professor Pitman has also played down the significance of the error in the IPCC’s report.

“There are two paragraphs that have been questioned in a 1600-page document,” he said.

“After two years, people have been going over that report with considerable care and have found a couple of errors of fact in a 1600-page document.

“I mean, we ought to be talking about the other 1599 pages that no one has found any problems with.”

Professor Pitman says he has no concerns about the IPCC’s reviewing process.

“We should be very clear on what the IPCC does. It writes a report that is fully open to external review. [Anybody] can each read over individual sections of the report and send in credible comments,” he said.

“So each government tries to pore over each of the statements to find fault with them and at the end of that process, future drafts are produced, again with opportunities for external examination and feedback.

“And you end up with a final report, which in this case some people have found one or two errors with after two years.

“I reckon that is a standard that most organisations would absolutely celebrate.”

Nevermind ‘glaciergate’ – here are the real holes in climate science

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The latest slandering of climate science in the press has been dubbed ‘glaciergate‘ – about the Himalayan glacial melt issue (see David Spratt’s response here). I don’t get quite why the denialist crowd seem to revel in non-issues, when there is much else to criticise about the IPCC, and much more obvious knowledge gaps in our understanding of climate as a whole.  Nature has a very detailed discussion of these ‘holes’ in climate science (regional climate forecasts, precipitation forecasts, aerosols and palaeoclimate data). It’s refreshing to see such a well written and open article discussing these gaps and ‘problem areas’ – as one scientist warned recently:

“This climate of suspicion we’re working in is insane. It’s drowning our ability to soberly communicate gaps in our science.”

The price of climate change skepticism?

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Ever laughed at the deniers who claim that climate scientists are in it for the money? Why not ask this: to what extent are the climate change deniers profiting from pedaling their anti-science spin? Just ask Lord Monckton, when his industry disinformation campaign hits the Australian shores this month:

Mr Smit said getting Lord Monckton to Australia came at a substantial cost and he was appealing to supporters for donations. “We have to fly Lord Monkton to Australia, cover all his domestic travel and accommodation and provide a stipend of $20,000 [£11,500],” he said. “Our aim is to cover these costs from donations from individuals, appropriate associations and corporations. We expect the required total to be about $100,000. We would like to keep the cost of admission to Monckton’s lectures to around $20 to maximise the number of people that will come to hear him. We have already had a number of offers of $1,000 and would prefer donations to be of that order, but of course any amount is very welcome. Should there be a surplus, this, depending on the amount, will be given to Lord Monckton and/or the Climate Sceptics Party which is assisting with this project.” (Read more from the Noosa Journal)

A stipend of $20k? For 14 days work? Profitable! Not bad for a man according to Crikey proclaims to:

… be a member of the House of Lords (well, he once tried to become one), to be a Nobel Laureate (he wrote a letter to the IPCC which won a Nobel Prize, a connection close enough for him to commission his own gold Nobel prize pin), to have single-handedly won the Falklands War (he persuaded the British Army to use germ warfare on the Argies), and to have invented a cure for Graves’ disease, multiple sclerosis, influenza, food poisoning, and HIV.

Here’s betting that Andrew Bolt will pen a column proclaiming Monckton as Australia’s saviour by the end of January! See Tim Lambert’s blog for a skillful deconstruction of Monckton’s previous climate nonsense.

Green sea slugs one up corals

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Corals are holobionts (host-symbiont partners) – the coral host living in symbiosis with algae (and an array of other micro-organisms, including bacteria, fungi, and other algae). The symbiosis from these algae provide the coral with nutrients, explaining why coral reefs thrive in nutrient poor waters. Problems then arise when temperatures get warm – the algae and coral become stressed, and the coral host kicks out the algae. If the temperatures are prolonged or severe enough, the coral host will inevitably die due to starvation and disease.

Enter the green sea slug. Instead of relying on a constant supply of intracellular algae within the host tissues, this slug can actually produce the photosynthetic pigment chlorophyll a, essentially allowing the creature to become self sufficient and solar-powered. Through horizontal gene transfer, the slug actually acquired algal ‘photosynthetic genes necessary to produce proteins, making the slug truly part animal, part plant. More below from Wired magazine:

Shaped like a leaf itself, the slug Elysia chlorotica already has a reputation for kidnapping the photosynthesizing organelles and some genes from algae. Now it turns out that the slug has acquired enough stolen goods to make an entire plant chemical-making pathway work inside an animal body, says Sidney K. Pierce of the University of South Florida in Tampa.

The slugs can manufacture the most common form of chlorophyll, the green pigment in plants that captures energy from sunlight, Pierce reported January 7 at the annual meeting of the Society for Integrative and Comparative Biology. Pierce used a radioactive tracer to show that the slugs were making the pigment, called chlorophyll a, themselves and not simply relying on chlorophyll reserves stolen from the algae the slugs dine on.

“This could be a fusion of a plant and an animal — that’s just cool,” said invertebrate zoologist John Zardus of The Citadel in Charleston, S.C.

Somali pirates and roving banditry

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Resilience Science just ran a post on a recent AP story that highlights the link between Somali pirates and recovering fish stocks in the region. Basically, increases in pirate activity has scared off the roving bandits –  fishing fleets from mainly from South Korea, Japan and EU – that have previously been exploiting the rich fishing grounds in the region.

Fishermen and sportsmen say they’ve been catching more fish than ever. Howard Lawrence-Brown, who owns Kenya Deep Sea Fishing, said fishing stocks over the last year have been up “enormously — across all species.”

“We had the best marlin season ever last year,” said Lawrence-Brown, who owns Kenya Deep Sea Fishing. “The only explanation is that somebody is not targeting them somewhere. … There’s definitely no question about it, the lack of commercial fishing has made a difference.”

I’m personally not convinced that overexploited fish stocks can recover on such short time-scales, but this is an interesting hypothesis. The story reiterates another interesting facet of the Somali pirate problem: that this phenomenon actually began as a way to protect Somali fishing grounds from foreign fleets. From another, earlier story from Time magazine

Ever since a civil war brought down Somalia’s last functional government in 1991, the country’s 3,330 km (2,000 miles) of coastline — the longest in continental Africa — has been pillaged by foreign vessels. A United Nations report in 2006 said that, in the absence of the country’s at one time serviceable coastguard, Somali waters have become the site of an international “free for all,” with fishing fleets from around the world illegally plundering Somali stocks and freezing out the country’s own rudimentarily-equipped fishermen. According to another U.N. report, an estimated $300 million worth of seafood is stolen from the country’s coastline each year. “In any context,” says Gustavo Carvalho, a London-based researcher with Global Witness, an environmental NGO, “that is a staggering sum.”

In the face of this, impoverished Somalis living by the sea have been forced over the years to defend their own fishing expeditions out of ports such as Eyl, Kismayo and Harardhere — all now considered to be pirate dens. Somali fishermen, whose industry was always small-scale, lacked the advanced boats and technologies of their interloping competitors, and also complained of being shot at by foreign fishermen with water cannons and firearms. “The first pirate gangs emerged in the ’90s to protect against foreign trawlers,” says Peter Lehr, lecturer in terrorism studies at Scotland’s University of St. Andrews and editor of Violence at Sea: Piracy in the Age of Global Terrorism. The names of existing pirate fleets, such as the National Volunteer Coastguard of Somalia or Somali Marines, are testament to the pirates’ initial motivations.

The Met on the cold weather

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The British meteorological office (The Met) has weighed in on cold weather in North America and parts of norther Europe (see their briefing here).  See their map (bel0w) indicating that most of the world is WARMER than usual and that the cold wave  is restricted to a relatively small terrestrial area.

…not cold everywhere in the world. North-east America, Canada, North Africa, the Mediterranean, and south-west Asia have all seen temperatures above normal – in many places by more than 5 °C, and in parts of northern Canada, by more than 10 °C. [see the map below]

Is it colder than average?

The mean UK temperature for December was 2.1 °C, making it the coldest for 14 years and colder than the long-term average for December of 4.2 °C. However, December was one of only two months in 2009 which had a below-average mean temperature.

What does this say about climate change?

Climate change is taking place as the earth continues to warm up.

In the UK, 2009 as a whole was the 14th-warmest on record (since 1914). This above-average temperature trend was reflected globally, with 2009 being the fifth-warmest year on the global record (since 1850).

The current cold weather in the UK is part of the normal regional variations that take place in the winter season. It doesn’t tell us anything about climate change, which has to be looked at in a global context and over longer periods of time.

The map shows that while it has been cold in Northern Europe, other parts of the world have seen above average temperatures.

Met director Richard Betts also posted an essay on the BBC on the current weather that also addresses the ongoing confusion over weather and climate (here).  Ill paste most of his essay below.

Recently, I gave a talk on climate change in my local village hall in Devon, and not surprisingly I was given a hard time.

In fact, it started two days before that. Cut off from work by the snow (which, incidentally, had been forecast with almost pinpoint accuracy), I was out with the kids and being teased by the other dads.

“Where’s all this global warming you’re always on about, ha ha!”

The usual stuff, leading to the usual somewhat nerdy discussion on the difference between weather and climate, which was then cut short when one of the children crashed their sledge and asked if we had got that on video to send to a TV show such as You’ve Been Framed.

Of course, we are seeing the same comments in some parts of the press and on Twitter, from those who jump on any bit of cold weather to say it proves that global warming is not happening and we’re all a bunch of idiots (or worse).

No matter how many times we say that “global warming” means a rise of average temperature across the world, decade by decade, and not every year being consistently warmer than the last in every place on Earth, there are still those that get this mixed up.

Yes, we have had the coldest December in the UK for 14 years and now we are having a big freeze in early January; but the UK covers less than half of one thousandth of the Earth’s surface.

Last year was actually the fifth warmest year on record as far as global temperatures were concerned.

The four warmest years were, in ascending order, 2002, 2003, 2005 and 1998. The last decade was the warmest on record, followed by the 1990s and then the 1980s, so the world is definitely warming up.

To be fair, people often make the same mistake but in the other direction, and link every heatwave, major flood, drought and famine to global warming.

Of course, we know that these things happen anyway, even without climate change – they may happen more often under a warmer climate, but it is wrong to blame climate change for every single event.

Climate scientists know this, but still there are people outside of climate science who will claim or imply such things if it helps make the news or generate support for their political or business agenda.

It’s easy to blame the media and I don’t intend to make generalisations here, but I have quite literally had journalists phone me up during an unusually warm spell of weather and ask “is this a result of global warming?”

When I say “no, not really, it is just weather”, they’ve thanked me very much and then phoned somebody else, and kept trying until they got someone to say yes it was.

Even if scientists themselves are not blaming everything on climate change, it still reflects badly on us if others do this.

We cannot simply say it is everyone else’s fault; we need to be very clear about what can be used as evidence for or against climate change.

Long-term, large-scale trends and the overall statistics of extreme weather events can and should be part of this evidence base. Individual weather events, from heatwaves to big freezes, cannot be used either to prove or disprove climate change.