Extreme Temperature Diary- Friday December 19th, 2025/Main Topic: Worst Case Climate Scenario for the United Kingdom – Guy On Climate
Dear Diary. Yesterday we delved into a forecast for how much the planet will be above average during 2026, which lands into my bucket of how fast the Earth is warming. Today we will look at an item residing in the other of my debatable buckets of how bad things will get under warming scenarios.
The Guardian is published out of Great Britain, so it’s no wonder that a lot of their climate reports are UK oriented. The one published yesterday paints a dystopian picture of Britain if global averages get as high as +4.0°C by the end of the 21st century. Residents of the UK and the rest of global citizens should be scared into action on climate after reading this:
So it's goodbye UK coastal #nuclear
‘Massive disruption’: UK’s worst-case #climate crisis scenarios revealed by scientists
Scientists say government must prepare for unlikely but ‘plausible’ 4C rise in temperature and a 2-metre rise in sea levels.
www.theguardian.com/environment/...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-18T16:35:46.111Z
‘Massive disruption’: UK’s worst-case climate crisis scenarios revealed by scientists | Climate crisis | The Guardian
Climate crisis
‘Massive disruption’: UK’s worst-case climate crisis scenarios revealed by scientistsScientists say government must prepare for unlikely but ‘plausible’ 4C rise in temperature and a 2-metre rise in sea levels
Flooding in Wraysbury, England, last year. Photograph: Daniel Leal/AFP/Getty Images
Damian Carrington Environment editor
Thu 18 Dec 2025
The worst-case impacts of the climate crisis for the UK have been laid bare by scientists, ranging from a scorching 4C rise in temperatures to a 2-metre rise in sea level. Another scenario sees a plunge of 6C in temperature after the collapse of key Atlantic Ocean currents, massively disrupting farming and energy needs.
The impacts, some of which are linked to climate tipping points, are seen as low probability but plausible. The researchers said the scenarios filled a gap in forecasting that had left the UK unprepared for extreme outcomes.
A second set of worst-case scenarios sets out the potential extent of extreme weather between now and the end of the century. These indicate that temperatures could soar in some months by up to 6C above average, while rainfall could be triple normal levels.
“The climate extremes we have mapped aren’t predictions, but they are plausible,” said Nigel Arnell, a University of Reading professor who led the study. “The UK has been planning without the tools to test against worst-case scenarios. We’ve now given decision-makers what they need to prepare for climate outcomes they hope never happen, but can’t afford to ignore.”
The probability of the extreme scenarios happening could not be calculated because of uncertainty about what action will be taken to tackle global heating and how the climate system will respond. Arnell said this made the analysis similar to national security risk assessments or the Bank of England’s stress tests for the financial system.
“You couldn’t have known what the probability of Russia invading Ukraine was, but you could have said this is what the consequences might be,” he added.
The worst-case scenarios could be used to inform the building of long-term infrastructure, such as new towns, nuclear power stations and urban drainage systems, Arnell said, adding that awareness of climate risks could speed the drive to cut fossil fuel emissions.
Published in the journal Earth’s Future, the analysis developed the worst-case scenarios using a combination of observed and historical experience, computer simulations and theory.
Global temperatures rising well above 4C by 2100 could happen if climate action collapses or if there are strong feedback loops such as the Amazon rainforest dying and releasing its enormous store of carbon. This would result in extreme and prolonged heatwaves and droughts hitting the UK in summer. Thousands of early deaths have already occurred in England in heatwaves with just a 1.3C increase in global temperatures.
Temperatures could also be driven up by about 0.75C if pollution from industry is sharply cut, the scientists said. This is because aerosol particles from burning coal and heavy fuels block sunlight from reaching the ground.
A major ocean current, the Atlantic meridional overturning circulation (Amoc) is weakening and losing stability because of global heating. It is one of the tipping points that most concerns scientists. A collapse beginning in 2030 would lead to 6C cooling in the UK.
“Agriculture would struggle enormously and water resources would be completely altered,” said Arnell. “Our heat and energy system would be completely caught out by changing winter energy demand. It wouldn’t happen overnight, but it would be massively disruptive.”
A collapse of even one part of Amoc, the sub-polar gyre, would reduce UK temperatures by 2.5C, the scientists said.
Global sea levels are already higher because of global heating but a rise of 2.0-2.2 metres around the UK by 2100 could occur if glaciers in Greenland and Antarctica collapse rapidly, flooding coastal cities and towns. Unlike the other scenarios, this possibility was already known to planners.
The worst-case scenarios do not take into account potential global problems including the devastation of food supplies and conflict.
The research was commissioned by the Met Office as part of the government’s climate resilience programme. A House of Lords report warned in 2021 that not enough attention was being given to low-likelihood but high-impact risks.
The Climate Change Committee, the government’s independent advisory body, has said the UK needs to “adapt to 2C and assess the risks for 4C”. Adaptation plans published in 2023 were criticised as being “very weak”.
A government spokesperson said: “Climate change is at the heart of this government’s agenda, both adapting for the future and becoming a clean energy superpower. It is vital that the UK is ready for the impacts and we are helping local communities become more resilient, including by building nine new reservoirs, as well as a record £10.5bn in government funding for new flood defences to protect nearly 900,000 properties by 2036.”
The government has requested an evidence review of climate risks from the CCC, which will be published in the spring. It has also asked for guidance on climate scenarios to be used in planning.
Here are some “ETs” recorded from around the planet the last couple of days, their consequences, and some extreme temperature outlooks, as well as any extreme precipitation reports:
Among the Christmas Day record highs to be set if current NWS local forecasts for 12/25 pan out:
—Albuquerque NM: 66F (current record 63 in 1955)
—Wichita KS: 69F (current record 68 in 2019)
—Oklahoma City OK: 76F (current record 73 in 2016)
—Wichita Falls TX: 82F (current record 78 in 2016)
— Bob Henson (@bhensonweather.bsky.social) 2025-12-19T06:48:13.920Z
Smart: RI has a statewide document prioritizing 10,000 crucial assets—infrastructure, healthcare facilities, emergency service—for adaptation funding. Bond proceeds will finance a state revolving loan fund for multi-million-dollar resilience projects; grants will fund smaller design efforts.
— Dr. Jeff Masters (@drjeffmasters.bsky.social) 2025-12-18T00:51:38.732Z
A September brookings.edu report, “Who Bears the Burden of Climate Inaction?”, found climate -driven changes in home insurance premiums, home energy costs, and smoke effects on mortality are $400-$900 per household per year, with much higher costs—upward of $1,300 a year—in the hardest-hit places.
— Dr. Jeff Masters (@drjeffmasters.bsky.social) 2025-12-18T00:39:15.513Z
Met Office: Global warming set to surpass 1.4C for fourth year running in 2026
www.businessgreen.com/news/4523467...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T13:51:23.442Z
The Trump administration says it will dismantle the National Center for Atmospheric Research, a cornerstone for American climate and weather science. I went on NPR today to explain what this could mean for climate research.
Listen here:
— Katharine Hayhoe (@katharinehayhoe.com) 2025-12-19T00:41:21.828Z
"A Democratic senator involved in the negotiations...said that Trump’s attempt to break up a premier weather and climate center based in Boulder, Colo., was like a “stick of dynamite” that exploded any chance of a bipartisan breakthrough on spending."
thehill.com/homenews/sen...
— Bob Henson (@bhensonweather.bsky.social) 2025-12-19T04:40:17.323Z
It’s scientifically and ethically wrong to say, “It’s too late to stop climate change.”
At Project Drawdown, we will never give up.
— Dr. Jonathan Foley (@globalecoguy.bsky.social) 2025-12-18T23:01:11.733Z
This is fascinating - and sad.
Only 37% of us think it's too late to act? That is a lie from the pit of the tar sands, my fellow Canadians!
As Christiana Figueres says, "We are only as doomed as we believe ourselves to be."
This is how we can change our future: bsky.app/profile/kath...
— Katharine Hayhoe (@katharinehayhoe.com) 2025-12-19T00:49:50.228Z
It’s California’s turn to share in the wealth of rain. But it will be too much, too fast for some as the Atmospheric River takes aim on the state. Flood Watches up for North/Central CA. Over the next week up to 15” of rain will fall. 1/
— Jeff Berardelli (@weatherprof.bsky.social) 2025-12-19T17:19:51.784Z
Rare “Particularly Dangerous Situation” alert issued by NWS Boulder, CO for Friday in the Foothills for gusts up to 100 mph!! It’s due to a strong “downslope” wind. Air accelerates downhill and also drys out, making for damaging gusts and potentially rapid fire spread.
— Jeff Berardelli (@weatherprof.bsky.social) 2025-12-19T04:41:47.187Z
This is the first "Particularly Dangerous Situation" Fire Weather Warning ever issued anywhere in the state of Colorado.
#COwx
— Chris Bianchi (@bianchiweather.bsky.social) 2025-12-19T00:34:08.095Z
Psst: Notice where this wind/weather data is coming from. It's coming from NCAR.
One tiny blip of the kajillion things NCAR does to improve/advance weather forecasting.
#COwx
— Chris Bianchi (@bianchiweather.bsky.social) 2025-12-17T18:52:20.458Z
100K+ customers in CO Front Range lost power Thurs from high winds + proactive shutdowns. More wind T/C. “Friday’s high winds may overlap with some communities impacted by today’s weather event, which means certain areas may be without power for more than three days.”
boulderodm.gov/update-from-...
— Bob Henson (@bhensonweather.bsky.social) 2025-12-18T14:41:03.246Z
This tree just came down on Pine St just west of Folsom St in Boulder. Winds already gusting to 100+ mph at NCAR Mesa Lab.
— Bob Henson (@bhensonweather.bsky.social) 2025-12-19T19:19:37.388Z
There is no way to stop climate change research at NCAR without doing irreparable damage to weather research. "The idea that you can just pull “vital” weather research activities out of a unique, vibrant scientific environment and expect that they will just continue to roll along is ludicrous."
— Dr. Jeff Masters (@drjeffmasters.bsky.social) 2025-12-17T19:13:37.623Z
Well, you're describing the Mariana Trench of ludicrous who currently occupies 1600 Penn
— (@cherishone.bsky.social) 2025-12-17T19:38:19.280Z
'Seemingly unstoppable growth of renewable energy worldwide 2025 Breakthrough of the Year'.
www.science.org/content/arti...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-18T23:31:57.200Z
China's current rate of Wind-Water-Solar (WWS) installations puts it on a trajectory to transition to 100% WWS
pubs.rsc.org/en/content/a...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T20:22:54.799Z
NESO : Britain could halve its energy spending by 2050 as decarbonisation cuts costs and shields the economy from fossil fuel shocks.
www.energylivenews.com/2025/12/11/t...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T11:47:47.580Z
UK power generated by #solar this year surpassed previous records.
www.edie.net/2025-officia...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T11:53:36.144Z
How to steer EVs towards the road of ‘mass adoption’ www.carbonbrief.org/guest-post-h...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T11:56:38.186Z
UK’s largest proposed datacentre is understating the scale of its planned water use.
www.theguardian.com/environment/...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T11:55:13.077Z
Fools never differ ...
bbc.com/news/article...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T13:50:27.048Z
'Nuclear power’s role in Japan is fading. The myths of reactor safety and energy needs can’t change that reality. '
thebulletin.org/2025/12/nucl...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T11:50:52.557Z
Optimal power system fully based on renewable energy for Iran by 2050 – Achieving zero greenhouse gas emissions and overcoming the water crisis
www.sciencedirect.com/science/arti...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T12:33:21.634Z
\Don’t stop be-leafin’: how urban greening can help save threatened species
www.theguardian.com/australia-ne...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T17:56:29.746Z
Sellafield, the most #nuclear polluted plant in UK is also on the Cumbrian Coast ...
Nuclear industry - one accident/incidentr away from turning into a vast stranded asset.
www.theguardian.com/world/2025/d...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T18:01:56.261Z
Cancer risk may increase with proximity to #nuclear power plants, with risk declining by distance, according to a new study led by Harvard T.H. Chan School of Public Health.
hsph.harvard.edu/news/cancer-...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T11:42:31.393Z
The risk of thyroid cancer in relation to residential proximity to #nuclear power plants: a systematic review and meta-analysis.
link.springer.com/article/10.1...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T12:38:34.353Z
Cheers !
www.newscientist.com/article/2501...
— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2025-12-19T13:56:32.708Z
