As it happened: UK MPs assess IPCC climate science report

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1240 – And that concludes today’s committee meeting on the fifth IPCC report. The decision to invite in a panel of scientists followed by a panel of sceptics led to some clearly divergent views, which the MPs will now have to mull over as they work on their review of the IPCC report. The discussions ranged from the technical thrashing out of the models used by the IPCC, from peculiar accusations that climate scientists are just not as bright as their counterparts in the fields of physics and maths. The final review will seek to explore the impact of the mammoth science report on national and international policymaking.

IN DEPTH: RTCC’s coverage of the fifth IPCC report

1231 – Bob Ward of the Grantham Institute at the London School of Economics writes in the Guardian that the choice of speakers at today’s committee hearing shows an increasing trend towards climate denial in Westminster:

“The bias towards representatives from the extreme fringe of the climate change debate is a victory for climate sceptic MPs on the committee, Peter Lilley and Graham Stringer, who were apparently unperturbed by the lack of British contrarians on whom they could call.

“But this balance between expertise and extreme ideology which the committee’s selection seeks to achieve is eerily reminiscent of the ridiculous Congressional hearings where Democrats usually invite mainstream scientists, while Republicans elevate lobbyists and campaigners to the status of ‘expert witnesses’.

“It is also the latest sign that the politics of climate change looks increasingly the same on both sides of the Atlantic.”

1229 – Laframboise makes the point that there’s still two installments of the IPCC to go. “Who’s going to read that?” she asks. The reports should just deal with the most interesting points, rather than creating “massive documents that no one’s going to read anyway”. MP makes the point that this could lead to accusations of bias over the information that the IPCC chooses to include.

1221 – Lindzen makes some below the belt comments about the credentials of climate scientists, suggesting the field tends to be the domain of the less intelligent scientists.

Richard Lindzen

Richard Lindzen

1216 – Laframboise, who has remained fairly quiet until now, calls for the IPCC to be abolished. She says the peer-reviewed system doesn’t work, and it is not independent from governments. “I’m not sure it can actually be reformed,” she says. “It has a culture that has been around for 25 years, and it’s very difficult to change a culture.”

1209 – Lindzen: “There is so much penalty to saying this is not an important problem that I don’t think many people would go out on that limb.”

1204 – MP Tim Yeo is getting irate with Lindzen: “The evidence that we’ve just had the hottest ever decade doesn’t seem to be conclusive proof that global warming has come to an end,” he says, refuting Lindzen’s claims that the slowing over the upward warming trend over the past fifteen years means climate change has stopped. Over this period, the planet has continued to warm, but at a slower rate than during previous decades. Lindzen gives a somewhat convoluted explanation as to why he never claimed this. There is a minor kerfuffle in the room. Tim Yeo seems unconvinced.


1157 – Nic Lewis says that it is “logical” that natural variability could have caused warming, just as it could have caused the global warming hiatus, and criticises the IPCC for not reflecting this – he says that it suggests the opposite is true.

1151 – “The impact of man’s emissions don’t really become very significant until the last 50 or 60 years. Before then, we are dealing with natural climate variability,” says Lindzen. He points to previous periods of warming earlier this century. “I just don’t personally think there is much to be said. Even if you say man led to all of it, it still suggests low sensitivity.”

A fifteen year period in which global warming has slowed has provided food for climate change sceptics, although there are well established hypotheses over why this is so. The longer the hiatus in global warming goes on, the harder it will be to support a hypothesis of high sensitivity, he adds – meaning that he believes the climate may not be as responsive to higher carbon dioxide emissions as scientists suggest.

1144 – Laframboise compares the IPCC to a trial where the jurors are biased. She says she has written a book “exposing” the prejudices of the IPCC. The MP tells her off for plugging her book.

1136 – The views of the current panel has provoked some scathing responses from climate scientists on Twitter.

In an emailed response to RTCC, Ed Hawkins, a climate scientist at Reading University, refuted claims by Lewis that observational evidence for climate sensitivity is lower than the complex models. “He fails to mention to the Committee that all the observationally-constrained estimates for climate sensitivity also require models to derive both the forcings themselves and the response to those forcings.”

1134 – Lindzen says that the UK is unwise to take action against climate change: “There would be no disagreement here that whatever the UK is deciding to do will have no impact on your climate. I think you will all agree it will have a profound impact on your economy. You are taking actions that you know will create problems but that does not tackle a problem.”

1118 – Donna Laframboise says that the IPCC is unduly influenced by politics at the end of the process. The Summary for Policymakers is reviewed by governments – it is a UN document – but the last panel of climate scientists, including IPCC scientists, insists that the final word lies with the scientists, and everything can be traced back to the full report.

1114 – Richard Lindzen insists that climate change does not pose a problem for humankind, and that there is no consensus that sea level is rising. He says he doesn’t understand how policymakers could read the Summary for Policymakers and use it to form policy.

1108 – New group of speakers up now. We’ve got Professor Richard Lindzen from the Massachusetts Institute of Technology, Nicholas Lewis, climate researcher, and Donna Laframboise, a Canadian feminist and journalist. Each has a background in denying the scientific consensus on climate change – so quite a change from the last panel.

1104 – Things are getting existential over in Westminster. “Why are we here?” asks one panellist. “Why have we survived? Is the atmosphere not more stable than the catastrophic predictions indicate?” he asks, referencing periods of higher CO2 in the planet’s history. “We weren’t around then with the sort of society we have now,” says Brian Hoskins, saying that the current socio-economic set up would make climate change a lot more difficult to deal with than it was in the past.

It's fine if IPCC scientists want to be activists, says Peter Stott (Source: Flickr/rudolf_schuba)

It’s fine if IPCC scientists want to be activists, says Peter Stott (Source: Flickr/rudolf_schuba)

1054 – Interesting question from the panel: can scientists be activists if they’re a part of the IPCC? Peter Stott says this is not a problem. “We are first and foremost scientists – our decisions are based on the science, not politics.”

1050 – The panel brings up some of the high profile mistakes of the IPCC in the past, including its notorious and unfounded claim that the Himalayan glaciers would have entirely melted by 2035. Brian Hoskins says that the list of errors is short. If one of his students submitted a 3,000 page report which contained one wrong paragraph, he would be pretty pleased.


1047 – As the panel moves on to discuss the integrity of the IPCC, here’s a link to the Netherlands report encouraging an annual process, mentioned earlier by Myles Allen. It outlines some of the questions that have been raised about the IPCC:

“The Fifth Assessment has been a particularly turbulent period for the Intergovernmental Panel on Climate Change (IPCC). The unfortunate mistakes in the Fourth Assessment, and the delayed response to these, unveiled serious vulnerabilities in the organisation, the process of producing reports, the perceived integrity of the people involved and the communication.”


1042 – The IPCC report itself is meant to be policy neutral but policy relevant, but Myles Allen has some of his own advice, when questioned about the doubt that remains over certain elements of climate science: “We should be thinking about policies to accommodate the uncertainties, rather than waiting for the uncertainties to go away.”

1036 – There have been criticisms of the somewhat unwieldy IPCC process in the past, which involves hundreds of scientists working for free over many years. Myles Allen says that there is a danger that the process and the document outweighs the evidence itself. “It will be significantly streamlined in the future.” He supports an annual assessment supported by special reports – a proposal that has been put forward by the Netherlands. “They’re very sensible people, the Dutch,” he says.

1029 – Hoskins says that the consensus view achieved through the IPCC is “not perfect”, but it is remarkable that it is there at all. There are thousands of climate scientists, most of whom would say that their view has been taken into account. “To actually get a consensus is not a natural thing for scientists, but it’s demanded by government and the UNFCCC process, so that they can have something clear to base their work on.”

Myles Allen

Myles Allen

1026 – The panel asks whether the findings of the IPCC support continued economic action to fight climate change. This is an important question for the UK, which is legally bound to cutting its carbon emissions through the Climate Change Act. Myles Allen says: “As long as emissions continue to increase exponentially, the long term committed warming continues at the same rate,” referring to the fact that CO2 remains in the atmosphere for thousands of years. “Until we bring our emissions close to zero, we’re going to see continued warming, and that has profound implications for policy.”

1020 – Why has confidence increased that humans are causing global warming, rather than natural variability? “We have a greater wealth of evidence now than we had, and improved models,” says Peter Stott.

1013 – Does the language of uncertainty need to be clarified, asks the panel. Hoskins says that the report does quantify the language it uses. For instance, if something is “very likely” means 90-100% confidence in the statement. Clear guidance notes means that the report is well calibrated to reflect how sure scientists are across the board based upon lines of evidence. Certainty that humans have caused global warming has increased.

“It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century,” says the most recent IPCC report.

Sir Brian Hoskins

Sir Brian Hoskins

1001 – Who are we listening to? Oxford’s Professor Myles Allen and the Met Office’s Peter Stott are both climate scientists. They were both lead authors in working group one of the fifth IPCC report, published in November. Sir Brian Hoskins was knighted in 2007 for his services to the environment. He is also a member of the UK’s independent Committee on Climate Change.

1000 – Have you forgotten what was in the last UN climate science report? Leeds University’s Piers Forster, a lead author on the study, summed it up in 18 tweets.

0951 – How do scientists deal with the claims of scientists such as Judith Curry that “natural internal variability has a larger role to play in anthropogenic CO2”, asks the panel. This deals with the criticism popular of climate change sceptics that natural changes in the environment are responsible for much of the warming that scientists have recorded. Peter Stott disputes the claim, saying: “We have found that the greenhouse effect dominates in the last 60 years.” Natural variability accounts for short term changes, but “they do not provide the very long term warming that we are seeing” as a result of global warming. It is about “disentangling these two” says Hoskins.

0944 – Issues about climate sensitivity are very hard to resolve, says Myles Allen. It is the “Katie Price of climate parameters” – everyone talks about it, but no one is quite sure why. Transient climate response is the more policy-relevant part of climate science, he says.

Too much jargon? Here’s how the Met Office describes “transient climate response”:

“The transient climate response is the change in the global surface temperature, averaged over a 20-year period, centred at the time of atmospheric carbon dioxide doubling, that is, at year 70 in a 1% per year carbon dioxide increase experiment with a global coupled climate model. It is a measure of the strength and rapidity of the surface temperature response to greenhouse gas forcing.”

0940 – Are there any risks of relying on the Summary for Policymakers? This short summary of the report draws out the main points of a document that is beyond the understanding of most politicians. Peter Stott of the UK’s office says that all of the statements in the Summary are “traceable back into the report”. Allen says that it is a process at work: scientists continue to check what other scientists have done, and the high profile statements made within the Summary are highly scrutinised.

0936 – Professor Myles Allen of the University of Oxford says it is important to keep uncertainties within the IPCC in perspective.

0933 – Sir Brian Hoskins, head of the Grantham Institute for Climate Change at Imperial College London, says that not a huge amount has changed in the fifth IPCC report compared to previous reports, but what is “particularly impressive” is the new level of specificity on the melting of Greenland and Antarctic ice sheets and their contribution to sea level.

0930 – The session has started…

0929 –  The first part of the Intergovernmental Panel on Climate Change’s 5th Assessment Report was published last September, analysing the ‘physical science’ of climate change. The findings – which you can read more about in our dedicated section – underpin UN negotiations aimed at agreeing a global emissions reduction treaty in 2015. One specific finding was that the world has what is called a ‘carbon budget‘, that’s to say a limit to the levels of CO2 that can be released before dangerous levels of warming are locked into the system.

0925 – Welcome to our live blog of this morning’s ‘evidence session’ into the IPCC 5th Assessment Review, held by the British MPs that make up the Energy and Climate Change Committee. I’m Sophie Yeo and you can get in touch with me via Twitter or by the comment form at the bottom of the page. Today’s meeting is important as it’s a chance for MPs to interrogate some of the leading scientists involved in the report – and some who say they are sceptical of its findings.


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