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Leon Simons 🌍 Profile picture
Leon Simons 🌍
@LeonSimons8
Host of Climate Chat | Plain climate science & DATAVIZ | Mission: To Understand and Protect the Home Planet
21 subscribers
Apr 18 • 4 tweets • 3 min read
If only people understood how significant this >10% decrease in cloud cover and the same amount of increase in sunshine duration are.

It would be front page news over all Europe media.

It's not even included in many (most?) regional climate models... Image Figuring out what underlying assumptions in models are is much harder than you'd think.

As if it's designed that way..

The Netherlands receives ~180 kW of additional sunshine for each hectare of its surface.

That the day and night, 365-day average.
Image
Mar 16 • 5 tweets • 2 min read
NASA: Global Sea Level Rise increased more than expected in 2024.

0.59 cm might not sound like much, but 2/3rds of that was due to thermal ocean expansion.

Which takes about 50 times more heat to increase sea levels than melting land-ice does!
1/ Image Ice melt: ~1.5 ZJ = 1 cm
Ocean heat: ~73 ZJ = 1 cm

We can use this to get a rough indication of Earth's Energy Imbalance in 2024:

(0.59 cm * 2 / 3 * 73 ZJ) + (0.59 cm * (1 / 3) * 1.5 ZJ) = about 29 ZJ of heat to increase sea levels by 0.59 cm.

Which is +1.80 W/m² globaly!

2/ Image
Feb 4 • 46 tweets • 12 min read
Global Warming Has Accelerated
Are the United Nations and the Public Well-Informed?
[No!]

Notes from the presentation of this groundbreaking new paper by James Hansen (@DrJamesEHansen) et al. (2025), with leading climate scientists:

🧵
1/Image @DrJamesEHansen Global warming has accelerated, which can't be explained by natural variability Image
Jan 27 • 14 tweets • 7 min read
Fossil fuels contain sulphur, which is released when burned. Scientists have known about the cooling effect of sulphur for decades.

This partially hides greenhouse gas warming.

But the scale of cooling and the decoupling of CO₂ and SO₂ emissions has been underestimated Image As more and more clean air regulations came into effect from the 1960s onward, CO₂ and sulphur dioxide (SO₂) emissions gradually decoupled.

SO₂ emissions reached a global peak around 1980:
academic.oup.com/bioscience/art…Image
Dec 29, 2024 • 8 tweets • 3 min read
🌊🌡️📈
The North Atlantic Ocean is not cooling back down.

The baseline has shifted.

We'll discuss this and more later today on Climate Chat. Image 2024 even broke the extreme Sea Surface Temperature record of 2023: Image
Dec 16, 2024 • 4 tweets • 2 min read
The Atlantic Ocean used to transport about 500,000,000 Hiroshima bombs worth of heat northward.

This will decrease by ~30% in OUR lifetimes.

What does that mean?

I think the main problem with climate change is that our tiny brains are incapable of comprehending it. I tried to cover the basic AMOC maths here:

patreon.com/posts/10867891…
Nov 22, 2024 • 7 tweets • 4 min read
🌊🌡📈 = 🦠📉

Plankton may not survive global warming, with "devastating effects"

🚨Plankton is at the basis of the ocean food web!
🚨Plankton sequesters carbon & releases oxygen!
🚨Plankton keeps the planet cool by creating cloud condensation nuclei! Image
Image
Image
Image This is one of the most worrying studies I've seen in a long time.

And I come across a lot of worrying studies.
oceanographicmagazine.com/news/plankton-…
Nov 15, 2024 • 15 tweets • 5 min read
🌍🌡📈
How close is +1.5 °C ?!

7 years away?
2.5 years away? 👇
4 months ago??

It very much depends on how you look at the data.
🧵 1/Image The average of the past 17 months was +1.60 °C above the 1850-1900 preindustrial baseline in the @CopernicusECMWF ERA5 dataset.

October was +1.65°C and November will likely be about the same.

While El Niño ended in May. Image
Nov 11, 2024 • 5 tweets • 3 min read
BREAKING 🌊🌡️📈

"All datasets agree that ocean warming RATES show a particularly strong increase in the past
two decades."

@WMO State of the Global Climate 2023 Report.

About 90% of the energy that has accumulated in the Earth system is stored in the oceans!Image @WMO @MercatorOcean This was highlighted today by @WMO's Secretary General State of Climate 2024 update

@borenbears asked the crucial question about 1.5 °C.

All these methods shown in their Fig 2 underestimate the rate of warming:

unfccc.int/event/wmo-stat…Image
Oct 20, 2024 • 10 tweets • 4 min read
"the probability of an AMOC collapse before the year 2050 is estimated to be 59%"

Looking and Atlantic heat transport reanalysis, relative sea ice anomalies, and model studies (including the effects of aerosols), I'm afraid the collapse of the AMOC might already be ongoing.. Reanalysis:

Oct 15, 2024 • 5 tweets • 2 min read
What the f*ck!

This is the most recent 12-month average Atlantic Ocean's Sea Surface Temperature Anomaly: Image This is not just about a single month or small region of the globe.

Our whole f*cking planet is in peril and most people are completely ignorant about it.

Often wilfully.
Oct 14, 2024 • 4 tweets • 2 min read
"The sudden collapse of carbon sinks was not factored into climate models – and could rapidly accelerate global heating"Image “We shouldn’t rely on natural forests to do the job. We really, really have to tackle the big issue: fossil fuel emissions across all sectors,” says Prof @PFriedling

“We can’t just assume that we have forests and the forest will remove some CO2 ..."
theguardian.com/environment/20…
Oct 7, 2024 • 6 tweets • 2 min read
Hurricane Milton has rapidly intensified to Category 5.

From Cat 1 in only 11 hours.

Gaining power at a rate of about 500 TW (terrawatt = 500,000,000,000,000 joules per second)!

This is equal to scale of Earth's Energy Imbalance, the rate at which our planet is warming. So much power:
Oct 3, 2024 • 4 tweets • 2 min read
Many are under the impression that we have not yet reached the double CO₂-equivalent Greenhouse Gas level.

We definitely have, using the @IPCC_CH's based estimates.

Don't ask me why nobody mentions this..

Total Greenhouse gas forcing:
4 W/m² = ~560 ppm CO2-eq = 2 x CO2Image @IPCC_CH Every climate scientist worth their salt knows and understands this.

Forcings are what cause the climate to change.

It's the first thing you (should) learn about when you study climate change. Image
Sep 18, 2024 • 5 tweets • 2 min read
This changes everything📈.
The Northern Hemisphere's Energy Imbalance.

The most important @NASA data you've never heard about.

The northern half of our planet started to absorb much more heat from the sun than it radiates to space.

These are absolute values (not anomalies):Image For the first time @NASA CERES satellite data shows the Northern Hemisphere absorbing more sunlight (48-month average of 242.2 W/m²) than the Southern Hemisphere.

The amount of absorbed sunlight increased by 0.6 W/m² more over the Northern than over the Southern Hemisphere: Image
Sep 16, 2024 • 4 tweets • 2 min read
As parts of Europe are flooding, remember how aerosols decreased rainfall.

We need extensive assessments of what the rapid desulphurisation means for extreme rainfall over Europe. 𝗜𝗺𝗽𝗮𝗰𝘁𝘀, 𝗔𝗱𝗮𝗽𝘁𝗮𝘁𝗶𝗼𝗻 𝗮𝗻𝗱 𝗩𝘂𝗹𝗻𝗲𝗿𝗮𝗯𝗶𝗹𝗶𝘁𝘆
The @IPCC_CH WG2 report barely mentioned aerosols, while:

"Anthropogenic aerosols greatly modify sub-regional precipitation changes, and their spatio-temporal changes are uncertain"
Aug 31, 2024 • 8 tweets • 4 min read
Wake up!
Image The past two months were similar to 2023.

We might not see pre-2023 monthly global average temperatures for a total of >30 months!

If the rate of warming has increased even more than we think, we might never experience pre-2023 temperatures again..


Image
Aug 27, 2024 • 16 tweets • 6 min read
🤖 AI can lie to you.

Don't trust it!

I asked a simple question: How much heat (in ZJ) does it take to increase global sea levels by one meter, only melting land ice.

It says it considers the density differences between 🧊ice & 🌊water (917 vs 1000 kg/m³), but it doesn’t.
1/ Image 2/
 I see more and more people trust AI to do their calculations for them.

As I showed here, it's more often wrong than right:

patreon.com/posts/11016073…
Aug 21, 2024 • 12 tweets • 4 min read
🚢🗞️🌡️📈
As climate science and journalism are finally starting to widely cover the effects of IMO 2020, there's still very little reporting on what will happen over the Mediterranean next year.

The introduction of Emission Control Area MED-ECA.

🧵:
Image The Mediterranean covers less than 1% of global oceans, while supporting 20% of seaborne trade! Image
Aug 6, 2024 • 6 tweets • 3 min read
Here's what happened.

A single cherry-picked dataset kept being used to imply others, including @NASA and @NOAA, were lying ("the truth is bad enough") about accelerated warming.

Now that single dataset has been updated and does show an acceleration.
This confirms what @NASA and @NOAA researchers (Loeb et al. 2021) found about the doubling in the rate of global warming (Earth's Energy Imbalance, which is mainly ocean warming, as those take up 90% of the additional heat) over the past ~20 years.


Image
Aug 3, 2024 • 7 tweets • 3 min read
May 2024 was the first month since February 2016 for which @NASA CERES satellite data shows a relatively strong negative monthly Earth Energy Imbalance.

For global warming to stabilize, the long term average needs to be zero.

Values climatology corrected. Image @NASA These are the monthly values.

A lot to see here.

I'll write a detailed explainer on Patreon (link in bio) once the data for June are available. Image