Ocean temperatures reach June record high

From The Guardian

Temperatures on the ocean surface have hit a record high, raising fears of another burst of extreme heat this summer.

On 21 June, temperatures outside the polar regions exceeded the extraordinary highs observed at the same time in 2023 and 2024, the Copernicus Climate Change Service said on Wednesday.

It warned the new peak would probably bring “consequences for weather patterns, global climate and marine ecosystems”, not least because it would coincide with the earliest phases of an El Niño event they forecast to be the strongest in decades.

When the previous ocean record for June was set in 2023, scientists described the trends as “worrying”, “terrifying” and “bonkers” because they were so far outside their expectations. That presaged an El Niño and a period of devastating global heatwaves, floods and storms.

That 2023 record has now been surpassed and much of the world is once again seeing an alarming rise in temperatures. Last month, the UK and many other countries in Europe sweltered amid new heat records while Antarctica experienced unprecedentedly balmy winter conditions.

Although the focus is usually on land temperatures, oceans give a fuller picture of how much the climate is being pushed out of balance by human-caused warming.

Surface temperatures are affected by solar radiation, water currents and the buildup of heat in the depths.

Oceans absorb more than 90% of the excess energy in the Earth system, which is primarily caused by burning fossil fuels, such as oil, coal and gas. That imbalance hit a record 23 zettajoules last year, more than double the average of the previous two decades.

As a result, the oceans are warming at an accelerating rate. In 2020, the amount of heat being added to the oceans was equivalent to about five Hiroshima bombs a second. Last year, it was closer to 11 Hiroshima explosions a second. The UN’s secretary general, António Guterres, has warned “Earth is being pushed beyond its limits”.

Scientists said it was too early to say whether the sea surface heating would prove temporary or even worsen because annual peaks are usually registered in July and August.

But Carlo Buontempo, Copernicus director at the European Centre for Medium-Range Weather Forecasts, warned it could indicate the beginning of a new phase, leading, once more, to uncharted territory: “With ocean temperatures at these levels and El Niño on the horizon, we are likely to see more temperature records fall in the coming months.”

Copernicus is part of the EU’s space programme.

We are not helpless.  

We can replace coal and gas power stations with wind, solar and batteries to at least 90% of total electricity generation.  We can replace petrol and diesel in land transport, in cars, light trucks, and buses, and we can switch diesel trains to bi-mode trains.  We can replace oil and gas heating with electric heating and/or heat pumps.  And 40% of all shipping emissions are produced just delivering fossil fuels around the world.   

Also, you can personally change things too.  Get balcony plug-in solar.  Get home plug-in batteries.  Nag your government until they make them legal.  Vote, vote, vote.  Stop eating meat, and if that's too hard, stop eating beef and mutton.  If you can afford it, when you replace your car, get an EV.  Outside the US, their up-front cost is now as low as petrol cars, and their running costs are much lower.

And you won't be spitting into the wind, because the world's biggest carbon-emitter, China, has probably peaked its emissions.  Even in Trump's US, though abolishing the incentives to switch to green alternatives has slowed bettrification down, EV sales have started to rise, and most of new generation capacity this year is renewables.  

Fossil fuel companies and the Right want us to give up.  Don't.

Record winter temperatures in Antarctica

 

On King George Island the landscape has changed from mostly white to brown, grey and green. Photograph: Luis Muñoz

From The Guardian

Temperatures in the Antarctic climbed above 15C this month, shattering the previous winter heat record for the usually frozen region and raising concerns about the speed of climate breakdown.  [Reminder: since this is the Southern Hemisphere, it is mid-winter now, the equivalent of December in the N.H.]

The new winter peak temperature was logged by the Argentinian Esperanza base on the Trinity peninsula on 6 June amid a protracted heatwave, when the maximum daily temperature exceeded zero degrees for three consecutive weeks.

Scientists said the high of 15.4C broke the previous record set at the same station in 1998 by 2C. “This is absolutely crazy,” said Raúl Cordero, an Ecuadorian climate professor at the University of Groningen. “It is also about 20C above normal for this time of the year. That is a huge anomaly.”

Unusually strong warm winds from the north blew across much of the Antarctic peninsula. One Chilean weather station, Boonen Rivera, registered temperatures of close to 13C, Cordero said.

On King George Island, 100 miles (160km) from Esperanza, researchers said the landscape had changed from mostly white to brown, grey and green after temperatures hit 4.6C on 6 June.

“Last weekend was very strange. The temperatures here went very high so everything outside melted,” said Luis Muñoz, a Chilean glaciologist. “Usually there is 20cm of snow and a lot of ice on the ground at this time.”

Muñoz said he and a colleague, Natalia Mestre, climbed to the 500-metre peak of the nearby Collins glacier last Wednesday and were surprised to find rain melting the ice. “There was a direct impact on the glacier, which should be receiving snow now. It should not be suffering ablation at this time of the year. This is obviously not good for the glacier.”

The Antarctic region is coming under increasing human pressure, directly in the form of resource exploration and tourism and indirectly through the burning of fossil fuels, which is heating the planet.

Scientists warn that some of the region’s biggest glaciers, such as Thwaites and Pine Island, are approaching or may even have passed a tipping point that could push up global sea levels by four metres. Antarctic ice melt has also been found to slow global ocean circulation.

Cordero said a single winter of heatwaves, no matter how amazing, would not by itself make a huge difference to sea levels, but it signified more alarming long-term trends. “This heatwave happened because of extremely strong westerlies,” he said. “This has been happening with increasing frequency since the 1980s, and that is known to be related to climate change.”

 We are doing too little to slash emissions.  We need to do it as soon as possible, not in 10 or 20 years' time.   In almost every country around the world, the combination of wind, solar and batteries is as cheap as or cheaper than coal and much cheaper than gas.  EVs, outside the US and Europe, are as cheap as petrol/diesel cars, and obviously much cheaper to run as well.  It's a marriage made in heaven: clean electricity to drive your vehicle fleet, and a huge mobile battery resource which helps stabilise the grid.  Let's just do it, instead of phaffing around.

Cleaner ship emissions adding to global heating?

The evidence suggests that the rate at which global temperatures are rising has increased from ~0.2 C per decade to just under 0.3 C per decade.  There's been a lot of debate about whether this is due to falling SO2 emissions or to fewer clouds.  It turns out the two may be connected.

A conflict-driven reroute of international ships exposed how dramatically cleaner fuel reduces cloud formation. The discovery strengthens climate models and highlights the complex trade-offs between cleaner air and planetary warming. Credit: Shutterstock

From SciTechDaily

Shipping Disruptions Spark an Unexpected Climate Opportunity

When militia attacks interfered with shipping routes in the Red Sea, few expected the consequences to reach the skies above the South Atlantic. For Florida State University atmospheric scientist Michael Diamond, however, the forced shift in cargo ship routes opened an unusual chance to explore a key climate question — How much do cleaner fuels change how clouds form?

In a study published in Atmospheric Chemistry and Physics, Diamond and FSU Department of Earth, Ocean, and Atmospheric Science graduate student Lilli Boss reported that recent fuel rules lowering sulfur content by about 80 percent also reduced cloud droplet formation by roughly 67 percent when compared with earlier high-sulfur fuels.

“The unexpected rerouting of global shipping gave us a unique opportunity to quantify aerosol-cloud interactions, reducing the largest source of uncertainty in global climate projections,” said Diamond. “When your ‘laboratory’ is the atmosphere, it’s not every day you can run experiments like this one. It was an invaluable opportunity to get a more accurate picture of what’s happening on Earth.”

Their findings could help sharpen climate models, offering scientists and policymakers clearer predictions and a better understanding of how environmental regulations support public health.

How Fuel Regulations Alter Cloud Behavior

In January 2020, the International Maritime Organization (IMO) required a major drop in sulfur levels in marine fuel in order to improve air quality. Ship exhaust releases aerosols, especially sulfate particles, that influence how clouds form and how bright they appear. These tiny particles encourage the formation of many small droplets, which produce brighter clouds that reflect more sunlight. This creates a cooling effect that has historically offset about one-third of the warming caused by greenhouse gases.

Despite this cooling influence, the impact of aerosols remains difficult to pin down. Greenhouse gases such as carbon dioxide, or CO₂, stay in the atmosphere for centuries, while aerosols remain for only days or weeks. Their short lifetime, combined with cloud variability, makes aerosol-cloud interactions the biggest source of uncertainty in climate projections.

Diamond’s previous research showed that after IMO 2020, clouds in major shipping corridors began forming with fewer and larger droplets. Researchers are still debating how the resulting increase in sunlight absorbed by the ocean may have contributed to the 2023 and 2024 marine heatwaves in the Atlantic Ocean. There is also ongoing disagreement about how much cloud cover decreased after the fuel regulations, with estimates ranging from about 10 percent to as high as 80 percent.

A Large-Scale Natural Test Emerges

Beginning in November 2023, attacks in the Bab al-Mandab Strait sharply reduced Red Sea traffic and shifted vessels toward the route around the Cape of Good Hope. This sudden change meant the South Atlantic region — an area highly sensitive to ship emissions because of its regular low-lying clouds — saw a dramatic surge in ship traffic.

Because this shift was caused by conflict rather than weather patterns or policy changes, scientists were able to observe cloud behavior driven solely by changes in ship emissions. Such direct cause-and-effect conditions are extremely rare outside laboratory settings, making this situation a valuable natural experiment.

Satellite measurements revealed a clear increase in nitrogen dioxide, or NO₂, across the southeastern Atlantic Ocean. NO₂ is released by ship engines and was not affected by the IMO 2020 sulfur rules, so it offered a dependable indicator of intensified ship traffic. This allowed researchers to compare cloud conditions before and after the fuel regulations under similar levels of shipping activity.

Key Results From the Analysis

Even though there were nearly twice as many ships operating in 2024, the overall reduction in cloud droplet formation was only slightly less pronounced than before IMO 2020. When Diamond and Boss compared NO₂ levels, which were unchanged by sulfur regulations, with cloud droplet numbers, which respond to sulfur emissions, they found a 67 percent decline in ships’ ability to modify cloud properties after the regulations took effect.

This provides strong additional evidence that cleaner fuels have weakened shipping’s influence on cloud formation and offers a clearer measure of how pollution and cloud behavior are linked, an important factor for improving climate simulations.

Why These Findings Matter

Understanding how clouds respond to aerosols remains one of climate science’s most challenging problems.

The new research helps reduce the uncertainty surrounding Earth’s energy balance, enabling policymakers to make more informed decisions as they weigh environmental protection and long-term climate goals. The results also highlight the complex trade-offs involved in air-quality regulations. Actions that protect human health can also influence the planet’s climate system in unexpected ways.

Although aerosols temporarily cool the atmosphere, the pollutants responsible for this effect pose significant health risks. Sulfur particles are linked to respiratory and cardiovascular disease, and the IMO regulation is estimated to have already prevented tens of thousands of premature deaths.

Reference: “Conflict-induced ship traffic disruptions constrain cloud sensitivity to stricter marine pollution regulations” by Michael S. Diamond and Lili F. Boss, 21 November 2025, Atmospheric Chemistry and Physics.
DOI: 10.5194/acp-25-16401-2025

2025 likely to be second hottest year

 From The Guardian

This year is “virtually certain” to end as the second- or third-hottest year on record, EU scientists have found, as climate breakdown continues to push the planet away from the stable conditions in which humanity evolved.

Global temperatures from January to November were on average 1.48C higher than preindustrial levels, according to the Copernicus, the EU’s earth observation programme. It found the anomalies were so far identical to those recorded in 2023, which is the second-hottest year on record after 2024.

World leaders have promised to keep the planet from heating by 1.5C (2.7F) above preindustrial levels by the end of the century. Scientists interpret the temperature target as a 30-year average, leaving a sliver of hope for meeting the goal after a period of overshoot even as individual months and years begin to cross the threshold.

“For November, global temperatures were 1.54C above preindustrial levels,” said Dr Samantha Burgess, the deputy director of Copernicus Climate Change Service. “The three-year average for 2023-2025 is on track to exceed 1.5C for the first time.”

The agency’s monthly bulletin found that last month was the third-warmest November globally, with “notably” warmer temperatures recorded across northern Canada and the Arctic Ocean. The month was marked by a series of dangerous weather events including cyclones and catastrophic floods that swept away lives and homes across south and south-east Asia.

Average temperatures have risen sharply as a result of the blanket of carbon pollution smothering the Earth, which has strengthened weather extremes from heatwaves to heavy rains, but continue to vary from year to year based on natural factors. Warming El Niño conditions boosted global temperatures during 2023 and 2024 but gave way to weakly cooling La Niña conditions in 2025.

Copernicus found 2025 was tied with 2023 as the second-hottest year on record. “These milestones are not abstract,” said Burgess. “They reflect the accelerating pace of climate change, and the only way to mitigate future rising temperatures is to rapidly reduce greenhouse gas emissions.”

Since the Paris climate agreement in 2015, planet-heating emissions have continued to climb – although the expansion of renewable energy has helped to curb the rise – along with average temperatures and the intensity of weather extremes.

The Copernicus findings echoed analysis from the World Meteorological Organization before the Cop30 summit in Brazil last month. The WMO found 2015 to 2025 would have been the 11 warmest years in an observational record that stretches back to 1850.

Source: Copernicus

Second hottest May ever

 From The Guardian

It has been an exceptionally dry spring in north-western Europe and the second warmest May ever globally, according to the Copernicus Climate Change Service (C3S).

Countries across Europe, including the UK, have been hit by drought conditions in recent months, with water shortages feared unless significant rain comes this summer, and crop failures beginning to be reported by farmers.

The new Copernicus data shows that May 2025 was the second-warmest May globally, with an average surface air temperature of 15.79C, 0.53C above the 1991-2020 average for May. The month was 1.4C above the estimated 1850-1900 average used to define the pre-industrial level. This interrupts a period of 21 months out of 22 where the global average temperature was more than 1.5C above the pre-industrial level.

Carlo Buontempo, director of C3S at the European Centre for Medium-Range Weather Forecasts (ECMWF), said: “May 2025 breaks an unprecedentedly long sequence of months over 1.5C above pre-industrial. Whilst this may offer a brief respite for the planet, we do expect the 1.5C threshold to be exceeded again in the near future due to the continued warming of the climate system.”

The 1.5 degrees is the climate target agreed by the 2015 Paris agreement. The target of 1.5C is measured over a decade or two, so a single year above that level does not mean the target has been missed, but does show the climate emergency continues to intensify. Every year in the past decade has been one of the 10 hottest, in records that go back to 1850.

Dry weather has persisted in many parts of the world. In May 2025, much of northern and central Europe as well as southern regions of Russia, Ukraine, and Türkiye were drier than average. Parts of north-western Europe experienced the lowest precipitation and soil moisture levels since at least 1979.

In May 2025, it was drier than average in much of north America, in the Horn of Africa and across central Asia, as well as in southern Australia, and much of both southern Africa and South America.

May also saw abnormally high sea surface temperatures in the north-eastern Atlantic, reaching the highest ever recorded, according to Copernicus.

The Woodhead Reservoir in Derbyshire. Photograph: Christopher Furlong/Getty Images

A sobering look at key climate indicators

 From Dr Aaron Thierry

A sobering look at some key #climate indicators from last year - CO2 Emissions in 2024 - Record High Coal - Record High Gas - Record High Oil - Record High (tied 2019)

www.carbonbrief.org/analysis-glo...

CO2 Concentrations in 2024 - Record High www.noaa.gov/news-release...

Rate of Increase in CO2 Concentrations - Record High insideclimatenews.org/news/2404202...

Surface Air Temperature - Record High First year over 1.5°C above pre-industrial climate.copernicus.eu/year-2024-se...

Ocean Heat Content - Record High phys.org/news/2025-01...

Planetary Albedo (reflectivity) - "declined over the 25 years of precise satellite data" www.columbia.edu/~jeh1/mailin...

Earth's Energy Imbalance - "More Than Doubled in Recent Decades" agupubs.onlinelibrary.wiley.com/doi/10.1029/...

Rate of Global Sea Level Rise - "doubled during the past three decades" www.nature.com/articles/s43...

"Oil and gas annual upstream capital expenditures rose by $63 billion year-on-year in 2023 and are expected to rise a further $26 billion in 2024, surpassing $600 billion for the first time in a decade." www.ief.org/focus/ief-re...

This makes depressing reading, doesn't it?  Yet we are not helpless.  If we stop eating meat, we can cut emissions by +-30%.  You could become vegetarian, replace cow's milk with plant milks, and cut your personal emissions.  That is entirely in your control.  It's your choice.  

Second, you can replace your petrol car with an EV, if you can afford it.  In some countries, the sticker price for EVs is already the same as for ICEVs (petrol/diesel cars).   In others, you'll need an above average income to do it.  

You can put solar panels on your roof.  Again, that costs, so you need to have the money.  But if you do, you can cut your emissions, and help save the world.

And you can vote, for the greenest party available, even if it's not perfect.

WE. ARE. NOT. HELPLESS.  Do something.

Ozzie summer second hottest on record

From The Guardian

Last summer was Australia’s second-hottest on a record going back to 1910, at 1.89C above the long-term average, according to data from the Bureau of Meteorology.

The second-hottest summer – coming after the second-hottest winter and the hottest spring on record – included the second-hottest January and the third-hottest December.

Only the summer of 2018/19, at 2.11C above average, was hotter.

Over the past 15 years, the data shows that only the summers of 2011 and 2001 have been cooler than the long-term average, taken from 1961 to 1990.

“Climate change is the primary ingredient for this summer’s heat,” said Dr Linden Ashcroft, a climate scientist at the University of Melbourne.

“You could not have made this hot summer cake without climate change. It will only get worse if we don’t stop burning fossil fuels.

“There is no way this could have occurred without a heating planet. Yes, this is the second hottest summer on record, but it will be one of the coolest in the 21st century.”

She said the heat had come despite La Niña-like conditions in the tropical Pacific which have in the past been associated with cooler conditions.

Data released by the BoM shows the heat was well-spread around the country, with all regions seeing average daily temperatures in the top six on record.

Last summer ranked second for the hottest daytime temperatures, and fourth-warmest for night-time heat.

On a state-by-state basis, all mainland states had average temperatures in their 10 highest on record for summer. Western Australia had its hottest summer on record, and also its hottest summer for night-time temperatures.

Summer rainfall across the country was only slightly below average, with South Australia and the NT particularly dry.

“I don’t think we should need convincing about climate change any more in Australia because we can feel it,” said Ashcroft.

“We see it in our plants, our weather observations, in our moods and in the decisions that we make. This heat affects people, but we do have the ingredients to stop it.”

The rise in temperatures is proportional to the level of emissions.  So, for example, to halve the rise in temperatures, we must halve the level of emissions.   Yet, emissions are far from falling: they're still rising.

The kettle

By Tjeerd Royaards 

Global sea ice reaches new record low

 From Prof Eliot Jacobson

Hottest January since 1940

 From Prof Eliot Jacobson

And still we do nothing to slash emissions.  And we've elected a climate-denying cretin to the White House.

Record global sea temperatures

 From Prof Eliot Jacobson

Since March 13, 2023, global sea surface temperatures have been setting daily records compared to the pre-2023 record high for each day, with the exception of 5 days in late December, 2024. Thanks to @leonsimons.bsky.social for the idea to graph this.

World temperatures still rising.

From Prof Eliot Jacobson

Daily global surface temperature updates were delayed a few days. They were finally posted this morning. And the records keep on falling. [The *temperatures* keep on rising] 

So glad El Niño is over and La Niña is helping cool things down ...

1.8 degrees above pre-industrial levels.  Yet still we do nothing.