Leon Simons
@leonsimons.com
Mission: To understand & protect the home planet.
Innovator, climate research & communication, social entrepreneur.
Board member Club of Rome NL
Innovator, climate research & communication, social entrepreneur.
Board member Club of Rome NL
"If this shift represents an excursion into a new normal, our future could be hotter faster than expected."
A year after this insightful study was published, the albedo and net flux over the Northern Hemisphere mid-latitude oceans keep decreasing:
www.science.org/stoken/autho...
A year after this insightful study was published, the albedo and net flux over the Northern Hemisphere mid-latitude oceans keep decreasing:
www.science.org/stoken/autho...
December 18, 2025 at 7:50 AM
"If this shift represents an excursion into a new normal, our future could be hotter faster than expected."
A year after this insightful study was published, the albedo and net flux over the Northern Hemisphere mid-latitude oceans keep decreasing:
www.science.org/stoken/autho...
A year after this insightful study was published, the albedo and net flux over the Northern Hemisphere mid-latitude oceans keep decreasing:
www.science.org/stoken/autho...
Also see the 3-year running mean graph:
December 17, 2025 at 10:59 AM
Also see the 3-year running mean graph:
As this is the first inadvertent aerosol experiment ever at this scale, we are still learning as more and more data comes in.
This is not just the direct effect, but also feedbacks, of course.
This is not just the direct effect, but also feedbacks, of course.
December 14, 2025 at 3:49 PM
As this is the first inadvertent aerosol experiment ever at this scale, we are still learning as more and more data comes in.
This is not just the direct effect, but also feedbacks, of course.
This is not just the direct effect, but also feedbacks, of course.
This graph by @hausfath.bsky.social falsely suggests we've now experienced most of the shipping desulphurization effects, while NASA CERES data indicates the opposite.
December 14, 2025 at 2:54 PM
This graph by @hausfath.bsky.social falsely suggests we've now experienced most of the shipping desulphurization effects, while NASA CERES data indicates the opposite.
There is much more warming in the pipeline than simple models suggest.
Especially regionally.
Observations trump simple models.
Global averaging of (outdated CMIP6) models is pretty much useless with regards to what most people care about:
understanding real world impacts.
Especially regionally.
Observations trump simple models.
Global averaging of (outdated CMIP6) models is pretty much useless with regards to what most people care about:
understanding real world impacts.
December 14, 2025 at 2:53 PM
There is much more warming in the pipeline than simple models suggest.
Especially regionally.
Observations trump simple models.
Global averaging of (outdated CMIP6) models is pretty much useless with regards to what most people care about:
understanding real world impacts.
Especially regionally.
Observations trump simple models.
Global averaging of (outdated CMIP6) models is pretty much useless with regards to what most people care about:
understanding real world impacts.
ASK US ANYTHING, before or during Climate Chat later today.
What questions do you have for us?
Please comment here or on YouTube:
www.youtube.com/live/LZTPZOA...
What questions do you have for us?
Please comment here or on YouTube:
www.youtube.com/live/LZTPZOA...
December 14, 2025 at 1:02 PM
ASK US ANYTHING, before or during Climate Chat later today.
What questions do you have for us?
Please comment here or on YouTube:
www.youtube.com/live/LZTPZOA...
What questions do you have for us?
Please comment here or on YouTube:
www.youtube.com/live/LZTPZOA...
Only in a relative sense.
December 13, 2025 at 6:18 PM
Only in a relative sense.
Heed the 'Stockdale Paradox':
"You have to, on the one hand, never confuse the need for unwavering faith that you will find a way to prevail in the end.
With on the other hand, the discipline to confront the most brutal facts we actually face.
And we're not getting out of here by Christmas."
"You have to, on the one hand, never confuse the need for unwavering faith that you will find a way to prevail in the end.
With on the other hand, the discipline to confront the most brutal facts we actually face.
And we're not getting out of here by Christmas."
December 12, 2025 at 10:30 PM
Heed the 'Stockdale Paradox':
"You have to, on the one hand, never confuse the need for unwavering faith that you will find a way to prevail in the end.
With on the other hand, the discipline to confront the most brutal facts we actually face.
And we're not getting out of here by Christmas."
"You have to, on the one hand, never confuse the need for unwavering faith that you will find a way to prevail in the end.
With on the other hand, the discipline to confront the most brutal facts we actually face.
And we're not getting out of here by Christmas."
🚨10 years after Paris:
As far as the recent past is any indication of the future, I don't expect we will see the 3-year average going down below +1.5°C much ever again...
As far as the recent past is any indication of the future, I don't expect we will see the 3-year average going down below +1.5°C much ever again...
December 11, 2025 at 10:11 PM
🚨10 years after Paris:
As far as the recent past is any indication of the future, I don't expect we will see the 3-year average going down below +1.5°C much ever again...
As far as the recent past is any indication of the future, I don't expect we will see the 3-year average going down below +1.5°C much ever again...
We need prepare for 3°C of global warming by 2050, as NASA satellite observations indicate it a possibility.
As Risk = Impact * Probability, the potential impact of billions of deaths makes the probability largely irrelevant.
3/3
As Risk = Impact * Probability, the potential impact of billions of deaths makes the probability largely irrelevant.
3/3
December 11, 2025 at 5:31 PM
We need prepare for 3°C of global warming by 2050, as NASA satellite observations indicate it a possibility.
As Risk = Impact * Probability, the potential impact of billions of deaths makes the probability largely irrelevant.
3/3
As Risk = Impact * Probability, the potential impact of billions of deaths makes the probability largely irrelevant.
3/3
Climate models underestimate the rate at which heat accumulates on our planet.
If our cookstove models underestimate heat input, the food burns.
Now it's our planet that's burning.
2/3
If our cookstove models underestimate heat input, the food burns.
Now it's our planet that's burning.
2/3
December 11, 2025 at 5:31 PM
Climate models underestimate the rate at which heat accumulates on our planet.
If our cookstove models underestimate heat input, the food burns.
Now it's our planet that's burning.
2/3
If our cookstove models underestimate heat input, the food burns.
Now it's our planet that's burning.
2/3
When we build sustainable energy technologies, we know that reality always trumps models.
This 'traditional' electric stove from Ethiopia has a power density of about 17,000 W/m².
Compared to this Earth's Energy Imbalance of 1.4 W/m² doesn't seem much.
But Earth's surface is 510 trillion m².
This 'traditional' electric stove from Ethiopia has a power density of about 17,000 W/m².
Compared to this Earth's Energy Imbalance of 1.4 W/m² doesn't seem much.
But Earth's surface is 510 trillion m².
December 11, 2025 at 5:14 PM
When we build sustainable energy technologies, we know that reality always trumps models.
This 'traditional' electric stove from Ethiopia has a power density of about 17,000 W/m².
Compared to this Earth's Energy Imbalance of 1.4 W/m² doesn't seem much.
But Earth's surface is 510 trillion m².
This 'traditional' electric stove from Ethiopia has a power density of about 17,000 W/m².
Compared to this Earth's Energy Imbalance of 1.4 W/m² doesn't seem much.
But Earth's surface is 510 trillion m².
"But I'd have you know that thes waters of mine
Were once a branch of the River Rhine
When hundreds of miles to the East I went
And England was joined to the Continent"
Rudyard Kipling
We can still find ~12,000 year old wood, washed ashore on our *new* Dutch beaches.
Were once a branch of the River Rhine
When hundreds of miles to the East I went
And England was joined to the Continent"
Rudyard Kipling
We can still find ~12,000 year old wood, washed ashore on our *new* Dutch beaches.
December 11, 2025 at 5:10 PM
"But I'd have you know that thes waters of mine
Were once a branch of the River Rhine
When hundreds of miles to the East I went
And England was joined to the Continent"
Rudyard Kipling
We can still find ~12,000 year old wood, washed ashore on our *new* Dutch beaches.
Were once a branch of the River Rhine
When hundreds of miles to the East I went
And England was joined to the Continent"
Rudyard Kipling
We can still find ~12,000 year old wood, washed ashore on our *new* Dutch beaches.
10 years after the Paris Agreement, we have reached a '3-year average global temperature anomaly of +1.5°C in 2 or more datasets'!
And we can't blame El Niño for this, as ENSO was on average negative during this period.
The Paris Agreement was doomed from the start..
And we can't blame El Niño for this, as ENSO was on average negative during this period.
The Paris Agreement was doomed from the start..
December 9, 2025 at 5:46 PM
10 years after the Paris Agreement, we have reached a '3-year average global temperature anomaly of +1.5°C in 2 or more datasets'!
And we can't blame El Niño for this, as ENSO was on average negative during this period.
The Paris Agreement was doomed from the start..
And we can't blame El Niño for this, as ENSO was on average negative during this period.
The Paris Agreement was doomed from the start..
Wet bulb temperatures are a beach.
December 8, 2025 at 5:57 PM
Wet bulb temperatures are a beach.
It's even more apparent when looking at the longer time frame.
Again, not the different y-axes.
(Most recent months for 2025 are not available yet from @climate.noaa.gov ERSST V5 here).
Again, not the different y-axes.
(Most recent months for 2025 are not available yet from @climate.noaa.gov ERSST V5 here).
December 8, 2025 at 5:02 PM
It's even more apparent when looking at the longer time frame.
Again, not the different y-axes.
(Most recent months for 2025 are not available yet from @climate.noaa.gov ERSST V5 here).
Again, not the different y-axes.
(Most recent months for 2025 are not available yet from @climate.noaa.gov ERSST V5 here).
That's correct.
It's even more apparent when looking at the longer time frame.
(most recent months for 2025 are not available yet from @climate.noaa.gov ERSST V5).
It's even more apparent when looking at the longer time frame.
(most recent months for 2025 are not available yet from @climate.noaa.gov ERSST V5).
December 8, 2025 at 5:00 PM
That's correct.
It's even more apparent when looking at the longer time frame.
(most recent months for 2025 are not available yet from @climate.noaa.gov ERSST V5).
It's even more apparent when looking at the longer time frame.
(most recent months for 2025 are not available yet from @climate.noaa.gov ERSST V5).
Extropical Sea Surface Temperatures where record high for both hemispheres (note the different y-axes):
December 8, 2025 at 4:42 PM
Extropical Sea Surface Temperatures where record high for both hemispheres (note the different y-axes):
This December to November year was the second warmest on record.
1/
1/
December 8, 2025 at 4:42 PM
This December to November year was the second warmest on record.
1/
1/
This is bad for my mental health!
The sick joke called the Trump administration took the @EPA Climate Indicators website offline on October 10, 'World Mental Health Day'...
I backed up the 800,000 year greenhouse gas graphs and data in the link below, please share!
The sick joke called the Trump administration took the @EPA Climate Indicators website offline on October 10, 'World Mental Health Day'...
I backed up the 800,000 year greenhouse gas graphs and data in the link below, please share!
December 8, 2025 at 2:30 PM
This is bad for my mental health!
The sick joke called the Trump administration took the @EPA Climate Indicators website offline on October 10, 'World Mental Health Day'...
I backed up the 800,000 year greenhouse gas graphs and data in the link below, please share!
The sick joke called the Trump administration took the @EPA Climate Indicators website offline on October 10, 'World Mental Health Day'...
I backed up the 800,000 year greenhouse gas graphs and data in the link below, please share!
'As scientists, we are increasingly being asked to tell the public the truth about the crises we face in simple and direct terms.
The truth is that we are shocked by the ferocity of the extreme weather events in 2023.
We are afraid of the uncharted territory that we have now entered.'
1/2
The truth is that we are shocked by the ferocity of the extreme weather events in 2023.
We are afraid of the uncharted territory that we have now entered.'
1/2
December 8, 2025 at 1:38 PM
'As scientists, we are increasingly being asked to tell the public the truth about the crises we face in simple and direct terms.
The truth is that we are shocked by the ferocity of the extreme weather events in 2023.
We are afraid of the uncharted territory that we have now entered.'
1/2
The truth is that we are shocked by the ferocity of the extreme weather events in 2023.
We are afraid of the uncharted territory that we have now entered.'
1/2
This is such a great visualization of the carbon cycle and of how humanity has completely altered it within a geological instant, by @rarohde.bsky.social:
December 7, 2025 at 11:17 PM
This is such a great visualization of the carbon cycle and of how humanity has completely altered it within a geological instant, by @rarohde.bsky.social: