Climate Science in the House of Lords

THB prompts a debate over what the IPCC really says about extreme weather

Sep 04, 2023

I’m in London this week, participating in an event sponsored by Lloyd’s of London on recent catastrophes, media reporting and what research and IPCC actually say about weather extremes — more on that later this week. Coincidentally, a member of the House of Lords, Rt Hon the Lord Lilley (Peter Lilley), shared with me a recent public exchange with another member, the Rt Hon Lord Benyon (Richard Benyon), who presently serves as the UK government’s Minister for Biosecurity, Marine and Rural Affairs. Both are members of the Conservative Party.

The exchange provides a fascinating window into how the assessment reports of the Intergovernmental Panel on Climate Change (IPCC) are received and understood by policy makers. Both Lord Lilley and Lord Benyon have science training, the former in physics at Cambridge and the latter in agriculture at Bradford College. Their exchange is substantive, respectful and illustrates many of the challenges present where science (and science assessment) meets policy and politics.

Their exchange began in late July in the House of Lords:

Lord Lilley: Does my noble friend agree that, in contemplating how we prepare for the future, we should take into account the science, as prepared by the Intergovernmental Panel on Climate Change, which is summarised in table 12.12 of Working Group I. It says that, though of course the temperature is expected to rise [even] if we follow the most extreme scenarios, as the noble Baroness, Lady Jones, has forecast, there is not expected to be, nor is there any sign so far of, any increase in droughts, floods, landslides or fires.
Baroness Jones of Moulsecoomb: It is happening!
Lord Lilley: Deny the science if you will.
Lord Benyon: My experience in talking to members of the Intergovernmental Panel on Climate Change, the Royal Society and some of the best experts in the world on this is that there is a very real danger. While I respect my noble friend in so many ways, I feel I will listen in this case to members of the Royal Society and the Intergovernmental Panel on Climate Change, because they are the guardians of knowledge on this.

In this brief exchange, Lord Lilley and Lord Benyon are each citing the IPCC, but it is clear they are talking past each other. Lord Lilley is citing a table from IPCC WG1 Chapter 12 that I have highlighted and discussed here at THB on several occasions. Fortunately, their conversation continues via (public) email exchange and I reproduce it in full below.

But first, have a look at the IPCC WG1 Chapter 12 Table 12.12 that is at the center of their discussion. The table summarizes where the IPCC expects a signal of climate change to emerge from the noise of natural variability (blue and orange, for increasing and decreasing respectively), for three time periods (to date, in 2050 under RCP8.5 and in 2100 under RCP8.5), and where it does not expect a signal to emerge (white cells).

What is notable about the table is the many white cells and the phenomena that they are associated with — please read this post for an explanation of why this is actually to be expected. Most are surprised when they first learn what the IPCC actually thinks about the detection and attribution of extreme weather, and some even deny the science.

Lord Benyon wrote an email to Lord Lilley shortly after their brief exchange in the House of Lords, with a much more detailed reply to his initial question. In return, just a few days ago, Lord Lilley provided his response to that reply, with his substantive comments nested within Lord Benyon’s original reply.

To facilitate reading their exchange I reproduce it in full below with the words of each clearly identified (with typos, emphases, etc. as in the original).

Lord Benyon:

Dear Peter,
Thank you for your letter and enclosure following your question to me in the Lords. I have done some work on this (with a bit of help!) and would make these points.
AR6 WG1 “Climate Change Information for Regional Impact and for Risk Assessments” p1856, is, I think, the document you deployed to back your main point.

Lord Lilley:

Correct.

Lord Benyon:

All the “blues” are showing where there's high/medium confidence that that phenomenon is increasing, and the “oranges” are high to medium confidence they're decreasing.

Lord Lilley:

Yes. The blues are predominantly directly related to rising temperature (Mean Air Temperature rising, more Extreme Heat, fewer Cold Spells, rising Mean Ocean Temperature) and the direct consequence of more heat (less snow and ice). The only indirect effect of consequence is Relative Sea Level.

Lord Benyon:

This chart shows a bunch of stuff that IS happening. But these are climate impact drivers, rather than climate impacts - this is the physical science chapter of AR6 from 2021.

Lord Lilley:

I am not sure what point you are making. The WG1 definition of a Climate Impact Driver (CID) is: “A climatic impact-driver is a physical climate condition that directly affects society or ecosystems.”
The scale of the impact will depend on the circumstances of the society or eco-system it affects. But I don’t see how you can have a climate change impact without a Climate Change Driver.

Lord Benyon:

These are climate features that are increasing or decreasing risk and are a factor in causing/driving climate impacts - where and how will depend on the areas being looked at - whether they're more or less vulnerable to melting ice, for example - but melting ice as a feature of the climate system that is contributing to/driving other things and causing climate impacts.

Lord Lilley:

Melting ice will only count as a CID if it “directly affects society or eco- systems”. True, melting ice will amplify global warming since less of the sun’s radiation will be reflected. This is incorporated in climate models. Again, I don’t see the significance of your point.

Lord Benyon:

The “oranges” and “whites” indicate decreasing and increasing (neither is good, because by definition we're looking at climate impact drivers - things that are driving climate impacts).

Lord Lilley:

Actually, CIDs can have a positive impact. The extended definition of CIDs in WG1 adds: “Depending on system tolerance, CIDs and their changes can be detrimental, beneficial, neutral, or a mixture of each.”

Lord Benyon:

I would argue that “whites” are not 'not happening' - they're the features of the climate system where there the science currently has low confidence "in the direction of change".

Lord Lilley:

As the Table says: White cells “indicate where evidence is lacking or the signal is not present”. I understand that the test is whether any suggested impact is distinguishable from the natural climate variability. If any putative CID is indistinguishable from natural variation, then any additional climate impact cannot be an appreciable amount. It is like testing a drug: if the response of a sample of patients administered the drug differs from that of the sample administered a placebo by no more than is likely to occur from normal variance, we say it has no significant effect.

Lord Benyon:

We can’t use it as an example of why climate impacts aren't happening.

Lord Lilley:

We can certainly use it as evidence that any climate impact is statistically insignificant or that any observed impact of a climate event cannot be attributed to (man-made) climate change.

Lord Benyon:

If you read WG2 (impacts, adaptation and vulnerability) which shows how climate impacts ARE happening, worse than expected, and getting worse rapidly, with nearly half the global population living in areas particularly exposed to them. This chart from WG1 (the physical science) is just about the science showing the multitude of aspects of the climate system that are contributing to driving those impacts - whether they're increasing or decreasing with any degree of confidence.

Lord Lilley:

There does appear to be a conflict between WG1 and WG2.   If so, they cannot both be correct. At a minimum this would suggest that we cannot say “the science is settled”.
You say the Table and WG1 is “just about the science”.   We are constantly (and rightly) told we must “follow the science” so I am astonished at the suggestion we set it aside if someone comes up with a less rigorous but more alarmist analysis than science will bear.   Anyway, I prefer to rely on the climate science (possibly because I studied physics at Cambridge) rather than WG2 which takes into account changes other than climate – e.g. social and economic changes and population movements.   WG1 warns us: “Importantly, the assessment of risk in WG2 considers hazards as only one component of an integrated assessment that involves their complex interaction with exposure and vulnerability of the systems at risk.”   So, if people move to Florida and build lots of real estate the impact of hurricanes will increase even if the frequency and intensity of hurricanes do not change.
On the other hand it may be that the authors of WG2 do not use the same objective measure of climate impact as WG1 (i.e. a change greater than natural variance).   The Summary for Policy Makers (which may not be written by the scientists who wrote the body of the report), which you quote, does present the evidence in rather misleading, propagandist and unscientific ways.   Just two examples:
First, it states “observed increases in areas burned by wildfires have been attributed to human-induced climate change” – giving the impression that there has been an overall increase in the area burned by wildfires.   In fact, evidence from NASA’s satellites show that: “the total number of square kilometres burned each year between 2003 and 2019 has dropped by roughly 25 percent”[1]. (Incidentally NASA say: “on an average day in August, NASA’s satellites detect 10,000 actively burning fires around the world” – so the impression given by the media that forest fires are rare and novel events, explicable only be climate change, is a nonsense.)
Second: it refers to “adverse impacts from tropical cyclones, with related losses and damages, have increased due to sea level rise and the increase in heavy precipitation” giving the impression that the number or strength of tropical cyclones have increased, whereas they have not.   The “related losses and damage” have indeed, increased but only because the number of people living and building in cyclone prone areas have increased (suggesting they find it worth the risk to live and invest in these warmer climes!).

Lord Benyon:

On the substance, you make one incomplete statement and one … how shall I put this … that I would question:
"though of course the temperature is expected to rise if we follow the most extreme scenarios..."
This is an incomplete statement, as under all scenarios, not just the most extreme scenarios, global temperatures are set to rise further above current levels.

Lord Lilley:

True. I was referring to the projections in table 12.12 which are based on the absurd RCP 8.5 (as, I suspect, were those in Baroness Jones’ question) which assumes that, far from making any attempts to phase out fossil fuels, the world switches ever more intensively to coal. On a more realistic scenario, and consequently more modest rise in temperature, these CIDs are even less likely to emerge.

Lord Benyon:

"...there is not expected to be, nor is there any sign so far of, any increase in droughts, floods, landslides or fires." I would argue that this statement is wrong, on two counts.
There is expected to be an increase in extreme weather and related problems.

Lord Lilley:

Which extremes of weather? I specifically referred to droughts, floods, landslides and fires. These are White in Table 12.12 – meaning no significant impact is expected to emerge before the end of the century. (I should have mentioned the possibility of pluvial floods -unlike river floods - becoming more apparent after 2050 - but in a Parliamentary Question one cannot give every detail). I could also have added that storms and cyclones have not, and are not expected to, become more frequent or severe.

Lord Benyon:

There are clear examples of extreme weather and related problems already happening, which can be attributed to climate change.

Lord Lilley:

True. But not those I mentioned: still less the likelihood of the UK suffering “multiple harvest failures; seaside erosion and mass evacuations; communities and towns collapsing from floods, fires and general devastation” as asserted by Baroness Jones, which you tacitly accepted.

Lord Benyon:

Paragraph IPCC WG2 (2022): B.1.1 Widespread, pervasive impacts to ecosystems, people, settlements, and infrastructure have resulted from observed increases in the frequency and intensity of climate and weather extremes, including hot extremes on land and in the ocean, heavy precipitation events, drought and fire weather (high confidence). Increasingly since AR5, these observed impacts have been attributed to human-induced climate change particularly through increased frequency and severity of extreme events. These include increased heat-related human mortality (medium confidence), warm-water coral bleaching and mortality (high confidence), and increased drought-related tree mortality (high confidence). Observed increases in areas burned by wildfires have been attributed to human-induced climate change in some regions (medium to high confidence). Adverse impacts from tropical cyclones, with related losses and damages, have increased due to sea level rise and the increase in heavy precipitation (medium confidence). Impacts in natural and human systems from slow-onset processes such as ocean acidification, sea level rise or regional decreases in precipitation have also been attributed to human induced climate change (high confidence).
· IPCC WG2 Summary for Policy Makers, part B: https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_SummaryForPolicymakers.pdf
· ECIU's WG2 infographic: https://eciu.net/analysis/infographics/ipcc-explainer-impacts-adaptation-vulnerability
I wish you were right – I really do! I am not some kneejerk catastrophist and look for good news wherever and whenever I can, but I am reluctantly driven to the conclusion that we are facing some very severe global events.
Best wishes
Richard

In his response to Lord Benyon’s reply, Lord Lilley included this preamble, which included a request for my input:

It would be very interesting to know a) whether your officials were aware of this rather important Table before I raised it in Parliament, and b) if so, whether they had alerted Ministers to it. I suspect the answer to both questions is: No. However, I appreciate that it would not be appropriate for you to say so since the essence of Ministerial accountability is that we are responsible for the advice we receive or don’t receive, take or don’t take. Nonetheless, it might raise questions in your mind as to whether the Department thinks its job is to convince Ministers of a particular alarmist perspective rather than giving them the balanced information to decide for themselves?
After all, the gist of your/their reply is that the IPCC has got the science wrong!
I think the IPCC has its faults, but its technical chapters provide an invaluable aggregation of scientific research. If it did not exist we would have to invent it.
I have sent our correspondence to Professor Pielke Jnr who is one of the world’s leading experts on climate impacts. He may well say my comments are rubbish, in which case I will grovel and retract!
Yours ever
Peter

My thoughts:

First, both I and THB readers thank Lord Lilley and Benyon for sharing this rich and detailed exchange. It is heartening to see policy makers intelligently discussing climate science and grappling with what the IPCC assessment is actually telling us. Thanks to Lord Lilley for inviting my input.

Some reactions:

The exchange reveals the degree to which the IPCC has — how shall I put this — buried the lede. The information in IPCC Table 12.12 is without a doubt among the most important information across all AR6 reports, and it was ignored by the Summary for Policymakers. You do not see the Table being promoted by the IPCC social media team or anyone else. Aside from the discussions initiated at THB, never been mentioned by scientists or the media (I’m happy to be corrected on this). If a signal of climate change with respect to the future behavior of most weather extremes is not expected to emerge with high confidence until beyond 2100, that would seem pretty important, no? Especially given the rampant misinformation on this topic currently being promoted by activists and the media. This issue should prompt some soul searching within the community of scientists who see their job as calling things straight.
The Lords’ exchange illustrates some important differences between claims made by IPCC WG1 and its Working Group 2. I and others have documented a slew of errors and false claims in Working Group 2 — here, here and here, for instance. I frequently have people citing WG2 (errors) to me to claim that WG1 is mistaken, rather than vice versa. On the physical science of climate change, WG1 has the appropriate expertise, but regardless which WG is believed to have the accurate view, it is remarkable that few seem to care that the IPCC can be so inconsistent across workings groups — surely a recipe for confusion and an opportunity for picking cherries.
My view on this is that the AR6 WG2 is simply so unreliable that I do not use it, even though the assessment report has a lot of good information. When standards slip, it becomes very difficult to distinguish signal from noise, sound science from overheated advocacy. of course, WG1 has a few errors that I have documented, but overall its AR6 assessment is much more reliable in my areas of expertise.
I am encouraged by the level of understanding and degree of engagement with the science shown by both Lords — no groveling or retraction required!

The actual science of climate change, as summarized in the full assessment of IPCC Working Group 1 indicates that:

climate change is real,
has already had detectable effects on the global climate system,
those effects are expected to increase,
with increasing risks to people and ecosystems

And also:

the following words do not appear in the IPCC assessment: existential, apocalyptic, catastrophic, emergency,
that a signal of changes in hurricanes, floods, meteorological or hydrological drought and other extremes has not yet emerged from historical variability, (though a few have, see Table 12.12 above),
and such signals are not expected to emerge until 2100, even under the most extreme (and implausible) scenario available to the IPCC.

As policy makers begin to better understand what the science really says — versus what they see in the media and hear from promoters of the apocalypse — it will be important to see if more pragmatic and effective approaches emerge on climate policy and politics.

Thanks again to Lords Lilley and Benyon!

The Honest Broker

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