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Chris Parker

@chrisjparker.bsky.social
3.4K followers 377 following 217 posts

Former Climate Lead @thecccuk.bsky.social - UK Climate Change Risk Assessment. "that uk hydrologist guy who knows about extremes" Hydrologist and climate scientist. Opinions my own. www.linkedin.com/in/chris-j-parker

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Chris Parker @chrisjparker.bsky.social · 18h
This is a systemic problem across physical climate impact and risk science. It's baked into the methods, and it's one of many reasons we're underestimating climate risk.
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Chris Parker @chrisjparker.bsky.social · 24/08/2026
Point 4 answers it for me "no one underwrites termination" is the whole risk I've been pointing at, confirmed. I think we're done here, appreciate the exchange.
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Chris Parker @chrisjparker.bsky.social · 24/08/2026
None of this answers who decides, who's liable, or who underwrites termination. "It's necessary" and "who's in charge" are different questions. You are answering the first one again.
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Chris Parker @chrisjparker.bsky.social · 24/08/2026
Do you also want to address the governance point? It is much more critical for SRM than for ER. Who gets to decide the SRM dial? What happens if a country doesn't like the outcome? Who's liable if it goes wrong and who underwrites the termination shock risk?
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Chris Parker @chrisjparker.bsky.social · 23/08/2026
I really don't get the logic. Setting aside the speculative nature of the technology, if we can't achieve global governance and commitments to effectively reduce greenhouse emissions why do we think we can do it for solar radiation management.
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Chris Parker @chrisjparker.bsky.social · 22/08/2026
It is very concerning. The recent extremes particularly of temperature are highlighting the limitations of climate models to project regional and local changes. This paper describes some of the issues with the CORDEx projections. www.nature.com/articles/s43...
nature.com
Exacerbated summer European warming not captured by climate models neglecting long-term aerosol changes - Communications Earth & Environment
Aerosol misrepresentations in many regional climate models largely explain why their simulations underestimate the summer warming in Western Europe in the past 40 years, according to a multi-model ana...
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Chris Parker @chrisjparker.bsky.social · 22/08/2026
From my reading of the website it is a 30 year average of the hottest 3 days not the actual hottest 3 days. Also they use Cordex models which are known to have a cool bias due to aerosol forcing.
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Chris Parker @chrisjparker.bsky.social · 06/08/2026
Typical BTI - selective quoting of IPCC and heavy reliance on their own controversial and contested work.
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Chris Parker @chrisjparker.bsky.social · 27/07/2026
Age of housing stock
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Chris Parker @chrisjparker.bsky.social · 14/07/2026
2°C global average. See CCC advice to Defra here: www.theccc.org.uk/wp-content/u...
theccc.org.uk
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Chris Parker @chrisjparker.bsky.social · 14/07/2026
Welcome news. Proud to have contributed through the CCRA4 climate framing and CCC advice on adaptation objectives. Now for delivery.
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Reposted by Chris Parker
Vikki Thompson @vikkithompson.bsky.social · 14/07/2026
🔥🥵🔥This summer the UK is experiencing unprecedented wildfires - many near urban areas. Following the heatwave of 2022 we showed climate change is leading to increasing fire weather in the UK. doi.org/10.1002/cli2... @hcbloomfield19.bsky.social @nathanaelmelia.bsky.social @climatedann.bsky.social
doi.org
Detecting Rising Wildfire Risks for South East England
In July 2022 southeast England experienced a record breaking heatwave and unprecedented wildfires in urban areas. We investigate fire weather trends since 1960 in southeast England using a large ense...
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Chris Parker @chrisjparker.bsky.social · 11/07/2026
Has Hansen updated his predictions for 2026/2027 for a potential record breaking El Nino? If I recall, his December prediction was for 12 month mean of 1.7°C for a moderate El Nino. I assume, given the potential for a record shattering breaking El Nino, that prediction will be closer to 1.8-1.9°C?
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Chris Parker @chrisjparker.bsky.social · 11/07/2026
If you check the next post in the thread....
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Chris Parker @chrisjparker.bsky.social · 11/07/2026
Something I could check.
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Chris Parker @chrisjparker.bsky.social · 11/07/2026
Do you use a spatial average for each city area or are you extracting a point? The numbers for London look low. Possibly due to ERA5 grid sizes and underestimation of extremes.
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
I got a bit sidetracked bsky.app/profile/chri...
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
Heatwave frequency, spatial extent and intensity are all increasing. That is what the figure captures and that is what is driving the increase risk from the hazard component.
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
I think you have to be slightly careful in how you interpret the change in distribution as this is also capturing the spatial extent. If you were to look at an individual grid cell the distribution shift wouldn't be as pronounced.
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
Here you go bsky.app/profile/chri...
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
Here is a bonus figure showing density plots for every 5km grid cell and every summer day for each decade since 1960 plus UKCP18 projections. The climate that exists today will no longer exist 10 years from now - that is how fast things are changing.
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
CCRA4 A Well Adapted UK Report showed adapting now is cost-effective and help protect the most vulnerable in society. The evidence and the tools point the same way: act now. 5/ www.theccc.org.uk/publication/...
theccc.org.uk
A Well-Adapted UK - Climate Change Committee
Footnotes have been removed from the HTML version of this report. For the footnoted version of this report,…
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
None of these are guaranteed summers but they are plausible ones. 1.5°C and 2°C of warming are already baked in, so scenarios like this are worth taking seriously now, not filed under "future problem." 4/
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
The infamous 1976 summer vs UKCP18 projections at 4°C of warming. 3/
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
2025, the hottest summer on record vs UKCP18 projections at 2°C of warming. 2/
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
🧵 With another UK heatwave in progress it's hard to show what future heatwaves will look like using maximum temperatures alone - so here's daily maximum temperatures across a whole UK summer, side by side: 2022, the summer with the first 40°C day vs UKCP18 projections at 1.5°C of warming. 1/
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
Had a quick scan - the out of sample validation doesn't seem great. And this seems like an overly complex way of doing basic DEM analysis.
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Chris Parker @chrisjparker.bsky.social · 10/07/2026
I recently created some density plots of daily maximum summer temperatures using 5km HadUK-grid cells per decade and one model run of UKCP18 Local projections. The change is quite stark for the 20s but it's nothing compared to what could be coming even under 1.5°C and 2°C warming.
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Chris Parker @chrisjparker.bsky.social · 09/07/2026
Shepherd et al 2018 paper on storylines provides a framework. More broadly it is about not treating climate projections as a probabilistic distributions and communicating limitations especially when models could be underestimating changes. link.springer.com/article/10.1...
link.springer.com
Storylines: an alternative approach to representing uncertainty in physical aspects of climate change - Climatic Change
As climate change research becomes increasingly applied, the need for actionable information is growing rapidly. A key aspect of this requirement is the representation of uncertainties. The convention...
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Chris Parker @chrisjparker.bsky.social · 07/07/2026
I was being pedantic in my original reply. I just think we should be clear about what data actually represents especially when there are known biases in said data.
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Chris Parker @chrisjparker.bsky.social · 07/07/2026
The aggregation point is fair but ERA5 is definitely a model and therefore not observations.
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Chris Parker @chrisjparker.bsky.social · 07/07/2026
Just to be pedantic - ERA5 is not observations. It is also likely to be underpredicting extreme temperatures. However, the UKCP18 convective permitting model (CPM) does a reasonable job. See Figure 1 from this paper: iopscience.iop.org/article/10.1...
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Chris Parker @chrisjparker.bsky.social · 07/07/2026
Heat waves today are already stretching us past our limits — and most people have no idea how much worse the next couple of decades will get. We're not prepared for what's coming. We urgently need better ways to communicate the scale of this risk.
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Chris Parker @chrisjparker.bsky.social · 06/07/2026
A 1.83C average for the rest of the year seems very unlikely. The North Atlantic is significantly cooler than 2024. That could change rapidly but if it doesn't I don't expect 2026 to be in the running.
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Reposted by Chris Parker
Met Office - weather and climate @metoffice.gov.uk · 26/06/2026
Today has been another record breaking day, with a new provisional June temperature record of 37.3°C recorded at Santon Downham this afternoon
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Chris Parker @chrisjparker.bsky.social · 26/06/2026
I can have a go at doing this with data I currently have.
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Chris Parker @chrisjparker.bsky.social · 26/06/2026
I am not sure it is possible to comment on westward shift based on individual event. I have just made similar figures for the Devolved Nations and extreme temperatures of 35-40+ are plausible in all regions at 2C of global warming.
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Chris Parker @chrisjparker.bsky.social · 26/06/2026
This shows a future heatwave day from the UKCP18 Local projections — essentially a heatwave day in the future compared to the 19 July 40°C day. The spatial pattern differs slightly for each heatwave, as you'd expect. These were selected based on peak max temperatures.
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Chris Parker @chrisjparker.bsky.social · 26/06/2026
Yes, saw those - excellent way to visualise it, similar to what we used in the Well Adapted UK report. But it still doesn't capture how frequently these events will occur, or how long they'll last. Some years in the climate projections are essentially one continuous heatwave.
Extreme heat is projected to become more widespread and severe across the UK as global temperatures rise, especially in southern and central England. Under 4°C global warming level by 2100, much larger areas reach temperatures above 40°C.
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Chris Parker @chrisjparker.bsky.social · 26/06/2026
The changes expected over the next decade or two will be increasingly stark — this event will look mild by comparison. We need to find a way to convey that with real urgency.
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Chris Parker @chrisjparker.bsky.social · 26/06/2026
We need to move beyond just heatwave magnitude. It's the combination of frequency, extent and magnitude driving increasing risk UK-wide — and daily max/min snapshots don't capture this fully. Reflecting on this post-CCRA, and I think it's a critically important point.
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Chris Parker @chrisjparker.bsky.social · 25/06/2026
Nicely sidesteps discussion of the many other heat related impacts that are currently occurring - road and rail disruption, interrupted water supplies, energy supply and demand challenges, flooding caused by thunderstorms. Not to mention the profound damages this is doing to nature.
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Chris Parker @chrisjparker.bsky.social · 25/06/2026
With UK heat extremes only getting worse, I'd bet most people get air conditioning long before they get a heat pump. There's a real opportunity to tackle heating and cooling together — but it needs the right incentives, skills, and workforce to deliver it.
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Reposted by Chris Parker
Peter Stott @stottpeter.bsky.social · 22/06/2026
We told you these heatwaves were coming but ghg emssions not yet going down (Stott et al, Nature , 2004 showing 2003 heat as regular occurrence). We're now saying West Antarctic ice sheet in imminent peril and huge irreversible sea level rise would result: would be good idea to listen this time.
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Chris Parker @chrisjparker.bsky.social · 22/06/2026
Spending my final week at the Climate Change Committee... during what might be a record-breaking UK heatwave. Almost like the climate read my leaving date and decided to make a point. 🥵🌡️
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Chris Parker @chrisjparker.bsky.social · 22/06/2026
This week marks my last at the Climate Change Committee, closing out 3.5 brilliant years. Proud to have led the climate science behind CCRA4 and the Well-Adapted UK report — work that will help shape how the UK adapts to a changing climate for years to come. Grateful for a brilliant team. 🌍
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Chris Parker @chrisjparker.bsky.social · 22/06/2026
Also, these ensemble sets are limited in size — just 16 models: 12 UKMO-HadGEM perturbed-physic ensemble and 4 CMIP6 models. That's not nearly enough to adequately assess the range of uncertainty. With a larger initial condition ensemble, I'd expect events of much greater magnitude to be possible.
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Chris Parker @chrisjparker.bsky.social · 22/06/2026
Worth noting this used the Met Office Convection-Permitting Model, which captures heat extremes much better. But I'm concerned the large-scale dynamics of the driving GCMs don't capture the frequency of these heat events - @hayleyjfowler.bsky.social has raised this for years.
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Chris Parker @chrisjparker.bsky.social · 22/06/2026
It uses RCP8.5, but with 20-year global warming level (GWL)–aligned timeslices. The driving GCMs warm rapidly, so the 2.5°C GWL timeslice occurs around 2030–2050, varying by individual model. Heatwaves at 4°C of warming reach maximum temperatures of ~48°C. www.metoffice.gov.uk/binaries/con...
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Chris Parker @chrisjparker.bsky.social · 22/06/2026
I don't know the details, but I expect the Met Office used the same approach as we did in A Well Adapted UK (Figure 1.6), at 2.5°C of warming. That approach uses the high-resolution (5km) UKCP18 Local data, selecting events from the time periods when each climate model reaches that level of warming.
Extreme heat is projected to become more widespread and severe across the UK as global temperatures rise, especially in southern and central England. Under 4°C global warming level by 2100, much larger areas reach temperatures above 40°C.
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