Leon Simons 🌍

Host of Climate Chat | Plain climate science & DATAVIZ | Mission: To Understand and Protect the Home Planet

[Leon Simons 🌍 @LeonSimons8]

This might be the year everything changes, as those who don't count joules and radiative fluxes are too starting to feel the heat from reducing air-pollution.

Many great scientists have tried to inform on this in the past decades (e.g. James Hansen, James Lovelock, Paul Crutzen and Veerabhadran Ramanathan).

Policy makers and media have paid very little attention so far.

This was the reason for me to start using my largely dormant Twitter account 3.5 years ago. To create awareness about rapid warming from rapidly reducing air pollution.

There's mainly been a small crowd of 'climate doomers' and slightly anoyed climate scientists to interact with.

In the past months this changed, as the additional accumulating heat is starting to surface.

My amount of followers has tripled, the graphs we make receive millions of views and media around the world are paying attention.

This is bigger than any one of us. We need specialized scientists to assess what this means for changes to monsoon systems, others that look at how ocean and atmospheric currents (might) change and how that could impact melting ice and sea level rise.

We need politicians, legal experts and social scientists to learn what is at stake and debate the effects of unintentional and intentional emissions on climate, not just health and the environment.

There are no easy choices in this.

How much warming will the world except? And how fast can the rate of warming be until we are unable to adapt?

When will we learn how high our dikes really need to be?

How extreme will droughts get?

How many people will lose their homes and need to move to greener pastures? Be it a locally overflowing refugee camp or to another country?

Will we have the stability of global governance to face these accumulating challenges?

Uncertainties are very large, which might be the main problem.
We don't know how bad it will get, and anyone who tells you one way or another is lying.

The precautionary principle tells us we have the duty to act.
For ourselves, for our children and for strangers we will never meet.

We are the most adaptable species known to ever have existed.

I believe that with a more thorough understanding of our planet, humanity could become a beneficial force to life on Earth.

If we soon aquire collective will to do so.

[Prof. Eliot Jacobson @EliotJacobson]

It cannot be re-stated enough that @LeonSimons8 has been the primary scientific voice pushing the narrative about the impacts of reduced sulfate aerosols on ocean temperatures. I'm grateful to see his tireless efforts finally being discussed by scientists and global media.

[Leon Simons 🌍 @LeonSimons8]

@UNEP For those who wonder, again no mention of aerosols (except for twice in the glossary..) in the new 112 page full report.

[Leon Simons 🌍 @LeonSimons8]

And another beautiful @UN @UNEP Climate report completely failing to cover aerosols...

Speaking of broken records.

'Limiting overshoot

Navigating exceedance of 1.5°C
and pathways towards return'

Reducing air pollution increases warming, especially regionally!

[Leon Simons 🌍 @LeonSimons8]

Fixed it, @UNEP

We cannot return to lower temperatures with only emission reductions and carbon capture and storage

Anyone who claims that is grossly negligent.

Misrepresention of inconveniet truths in order to give people false hope is very dangerous.

[UN Environment Programme @UNEP]

The chance to keep global warming below 1.5°C with no overshoot is gone.

But urgent action can still limit the overshoot and bring warming back to 1.5°C by 2100.

Current policies, however, put the 🌎 on course for up to 2.8°C this century.

New #EmissionsGap Report: https://t.co/rGd9ce8tTv

[Leon Simons 🌍 @LeonSimons8]

@UNEP Fixed it

[Leon Simons 🌍 @LeonSimons8]

Fixed it, @UNEP

We cannot return to lower temperatures with only emission reductions and carbon capture and storage

Anyone who claims that is grossly negligent.

Misrepresention of inconveniet truths in order to give people false hope is very dangerous.

[Leon Simons 🌍 @LeonSimons8]

It's a fair question to ask, if people get more hot-headed as Europe rapidly heats up.

Research shows a correlation between temperature and murder/attempted murders, for example:

[Dr. Robert Rohde @RARohde]

The riots in France have multiple complex economic and social causes, but I have to wonder whether the scorching hot summer contributed some to the discontent.

In a country where most homes and businesses lack air conditioning, this last summer would have been insufferable.

[Ben Noll @BenNollWeather]

Subsurface temperatures in the equatorial Pacific have soared 12°C (21.6°F) above average, the highest of this El Niño, with actual temperatures reaching 33.4°C (92.1°F).

The y-axis maximum was raised again to accommodate this extreme warmth.

We are witnessing climate history.

[Leon Simons 🌍 @LeonSimons8]

What's especially "problematic" is the continued conflation of the "warming pauze" narrative pushed by climate change deniers and the factual (more than?) doubling of global warming, which is based on real climate science (and acknowledged by NASA, NOAA, WMO etc).

[Zeke Hausfather @hausfath]

While there is increasingly strong evidence that global warming is accelerating, we need to be careful about how we detect it. Unfortunately a newly published paper on the topic makes a number of mistakes in it approach, as I discuss over at The Climate Brink: https://t.co/q18pXOcKt8

[Leon Simons 🌍 @LeonSimons8]

Source of the SST graph:
https://t.co/aefkQZnDCY

[Leon Simons 🌍 @LeonSimons8]

"The “statistial significance” of this model is overwhelming, i.e. we can resoundingly reject the hypothesis that global average SST has warmed at the same rate for the last several decades.
It’s a lot faster now (about 0.3°C/dec) than it was before 2012 (less than 0.1°C/dec)."

[Leon Simons 🌍 @LeonSimons8]

Many would call this a trippling of Sea Surface Temperature increase.

Which isn't very surprising, as Earth's Energy Imbalance has tripled and 90% of global heat accumulation is directed to warming the oceans.

[Leon Simons 🌍 @LeonSimons8]

The extreme surface heat in the Western Mediterranean results in extreme weather in the region.

[Dr JJ González Alemán @glezjuanje]

Dos eventos de precipitación de más de 700 mm en dos años!

Cualquiera en los años 80-90 te diría que algo así es virtualmente imposible. Pero hoy ya no estamos en ese clima, estamos en una nueva realidad climática que te puede producir estos eventos con facilidad, qué barbaridad...

No queda otra que adaptarse. Adaptación y preparación.

Y no solo esto es espectacular, lo que ha ido ocurriendo estas últimas semanas no son para nada propias de un otoño típico del Mediterráneo.

[New Scientist @newscientist]

El Niño has already raised sea levels in part of the eastern Pacific by 40 centimetres and as it continues to strengthen there could be coastal flooding from Alaska to Chile.

[Leon Simons 🌍 @LeonSimons8]

Startin soon!

[Leon Simons 🌍 @LeonSimons8]

Join us tomorrow and ask your questions below.

Climate Chat: Climate Updates & Ask Us Anything with hosts Dan Miller & Leon simons

Link below

[Leon Simons 🌍 @LeonSimons8]

@ElectroBOOMGuy This also works, is much cheaper and arguably more fun.

[Leon Simons 🌍 @LeonSimons8]

Nice trick.
We gave our kids something similar for their birthday.

[Leon Simons 🌍 @LeonSimons8]

See the link for time in your region and hit the bell button to get a notification when we go live:
https://t.co/bgY1zory2A

[Leon Simons 🌍 @LeonSimons8]

Join us tomorrow and ask your questions below.

Climate Chat: Climate Updates & Ask Us Anything with hosts Dan Miller & Leon simons

Link below

[Leon Simons 🌍 @LeonSimons8]

Nice trick.
We gave our kids something similar for their birthday.

[Tesla @Tesla]

Real life, baby

[Leon Simons 🌍 @LeonSimons8]

Vindication of Hansen et al.:
"The rate of global warming appears to have accelerated, rising from ∼0.05°C/decade between 1880 and 1970 to ∼0.19°C/decade between 1970 and 2010, and finally to ∼0.36°C/decade between 2010 and 2024
[...]
The acceleration may be partly related to reductions in aerosol pollutants that previously masked a portion of greenhouse gas warming (@DrJamesEHansen et al. 2025)."

Rectifications by media and certain vociferous scientific voices are in order.

[Jeff Berardelli @WeatherProf]

New paper by the World’s most prominent climate scientists shows rapid acceleration of human-caused warming, with a warming rate now that tracks to near 2.4°C by 2050, far faster than was expected, if it continues.
From paper: “We are witnessing the rapid destabilization of the Earth’s climate system. This is no longer a warning for the future; it is a diagnosis of the present. Earth’s life-support systems are being pushed beyond stable limits, with changes unfolding faster than our ability to respond. Human activities are driving profound shifts in the atmosphere, oceans, and biosphere.”
Paper Link in replies… H/T @LeonSimons8 …

[Leon Simons 🌍 @LeonSimons8]

@QSkies40093 No. Aerosol forcing won't increase again, but rather continue to decrease from reducing air pollution. And feedbacks are still coming into effect.

[Leon Simons 🌍 @LeonSimons8]

Vindication of Hansen et al.:
"The rate of global warming appears to have accelerated, rising from ∼0.05°C/decade between 1880 and 1970 to ∼0.19°C/decade between 1970 and 2010, and finally to ∼0.36°C/decade between 2010 and 2024
[...]
The acceleration may be partly related to reductions in aerosol pollutants that previously masked a portion of greenhouse gas warming (@DrJamesEHansen et al. 2025)."

Rectifications by media and certain vociferous scientific voices are in order.

[Leon Simons 🌍 @LeonSimons8]

Link:
https://t.co/Usj8MSxVG6