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Nov 5, 2021 27 tweets 10 min read Twitter logo Read on Twitter
Climate Impact of Decreasing Atmospheric Sulphate Aerosols and the Risk of a Termination Shock

Today I presented our first findings during the Annual Aerosol Science Conference of @AerosolSociety

@DrJamesEHansen @SkyECHO_Yann #COP26

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Significant reduction in atmospheric sulphate aerosols contributes to albedo reduction, acceleration in Earth’s Heating Rate and could cause an aerosol termination shock.

Global warming to date is caused by greenhouse gases, but sulfur emissions cool ~-0.5°C, hiding part of warming.

Global shipping was responsible for a large part of anthropogenic emissions of sulfur over oceans.

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Most Earth Heat Gain from increased greenhouse gas concentrations warms oceans, which cover 71% of Earth surface and absorb ~89% of heat gain.

Sulfur emissions from shipping reduced with ~80% from 2020 from regulation of the International Maritime Organization (IMO2020).

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Emission regulation of IMO decreased sulfur emissions over seas and oceans over Emissions Control Areas, with ~90% from 2015 and globally with ~80% from 2020.

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Models show large uncertainties in the effect of the ~80% reduction in global shipping. The low end would't be measurable and the high end could result in rapid regional and global warming.

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Differences in forcing estimates are caused by uncertainties in aerosol load, atmospheric lifetime, relative emission of direct SO4, DMS, emission distribution and seasonal variability.

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The past two decades saw an albedo decrease and an increase in planetary heat uptake, coinciding with a decrease in anthropogenic sulfur emissions.

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This trend could accelerate further with more sulfur emission reductions.

An aerosol termination shock whereby rapid anthropogenic aerosol emission reductions cause rapid global warming, can not be excluded.

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Reflection of Earth (Albedo) is decreasing. Sulfur emission reduction could be a leading cause.
With less solar radiation reflected back to space, warming is accelerating.
Ship sulfur emission reduction contributes to rapid albedo decrease over the N Pacific and Atlantic Oceans. Image
Compliance to low sulfur fuel regulations for shipping looks very strong, based on inspections of compliance, low sulfur fuel sales and scrubber installations.

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There already is an observed increase in the rate of Earth net heat uptake.

More solar radiation is absorbed from a decrease in cloud cover and surface albedo (mainly from melting of ice).

A warmer Earth radiates more heat, while more water vapor and other GHGs absorb IR.

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A well documented change in emissions and cloud changes happened over Europe since the 1980s

Large scale reduction in SO2 emissions coincided with a cloud cover reduction of ~5% and an increase of annual sunshine of ~75 h/yr.

Global & European temp increase accelerated.

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Rapid reduction of SOx emissions from global shipping could prove an unintentional abrupt cessation of SRM.
If the higher range ERF effects of IMO2020 are a reality, this could be quantified a termination shock, even more so when combined with other SOx reduction effects.

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There is a strong upward trend in the increase of Absorbed Solar Radiation globally and even more pronounced over the N Pacific Ocean and N Atlantic Ocean, both areas of high shipping density, where sulfur emissions were reduced the last decade and more from 2020.

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The North Pacific is a region of 37.1 million km² and if the trend of increase heat uptake continues, this could have significant consequences for the regional and global energy balance and climate.

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The North Pacific Ocean absorbs about 80'000 GW more solar heat since 2020 than before 2010, which is before any significant sulfur regulations for shipping came into effect.

On the other side of the Arctic Ocean is the North Atlantic Ocean. This region of 22.2 km² now absorbs about 50'000 GW of solar heat more than in the period before ship regulations.

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Total absorbed solar heat increase in these two regions is ~130'000 GW. Compare this to the average total human energy use of about 19'000 GW.

This is a lot of additional heat available to warm seawater, melt ice, heat the atmosphere, increase rainfall, storm intensity etc.

With the limited time since the IMO 2020 regulation has come into effect, the long term effect of this significant reduction in sulfur emissions is still uncertain.
Natural variability (ENSO, volcanoes, forest fires, dust storms) can temporarily change the radiation balance.
Human aerosol emissions and reduction thereof will keep impacting the climate.

Further global reduction in sulfur emissions is expected from health and environmental policies, cleaner fuel use and installation of desulfurization systems, mainly at coal fired power plants.

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*22.2 million km² that is of course..
This an updated and improved version of the graph. Image
These desulfurization systems are enormous.
These images show the decommissioning of a flue gas washer at an old coal fired powerplant in The Netherlands.

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Europe saw the largest quantity in sulfur emissions in the world, about 60 million tonnes SO₂ per year around 1980.

Therefore the largest effect of reduction in emissions is expected and seen over Europe:

On shipping emissions, see also this thread:

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More from @LeonSimons8

Sep 19
The August global Sea Surface Temperature really was something else..

See monthly anomalies since 1940
1/ Image
For those who keep saying that the ocean surface temperatures in shipping areas only started to increase faster this year,

see summer and monthly anomalies for the Northern Hemisphere mid latitudes:

This was expected through understanding of the cooling effect of sulphate, and from the observed increase in Absorbed Solar Radiation in the region:


Read 7 tweets
Sep 3
The most important graph in the world has been updated to include the last 150,000 years!

📄 Benthic δ¹⁸O records Earth’s energy imbalance

Great work by Sarah Shackleton, Alan Seltzer, Daniel Bagenstos and Lorraine Lisiecki (2023) in @NatureGeosci

This shows the Earth's Energy Imbalance from a new perspective.

We have changed the rate at which heat accumulates on our planet beyond anything ever before.

We are finding out what this means together.

And we better pay attention.

Rapid changes come with great risks!

2/2 Image
The paper has a very insightful "agnostic" approach to Earth's Energy Imbalance of the past, by looking at differences in oxygen isotopes from a sea level (water turning to ice and vice versa) and global ocean temperature perspective.

It doesn't seem to matter very much what the heat was directed towards, if you mainly care about the absolute Earth Energy Imbalance numbers.

More in this infographic and description:

Agnostic reconstruction of Earth’s energy imbalance (EEI) from δ18Obenth. Here we outline the steps taken to calculate EEI from δ18Obenth (left to right), which are described in detail in the methods. Briefly, δ18Obenth21 (left) is converted into sea level (second panel, top in yellow) and ocean temperature (second panel, bottom in green) using the assumption that the δ18Obenth signal is entirely attributed to one or the other. We then calculate the energy change associated with ice sheet buildup/melting from the sea level reconstruction (third panel, yellow) and with ocean warming/cooling from the ocean temperature reconstruction (third panel, green). EEI is then calculated by taking the time derivative of the energy changes and averaging over Earth’s surface area (panel 4). The gray lines in panels 3 and 4 show the calculated the global energy change (ΔEglobal) and EEI if we assume a constant 60/40 split of δ18Obenth between ice volume and ocean temperature changes.

Read 7 tweets
Aug 13
😳What the f*ck😳

Sometimes I can't help myself and swear.

Two months ago, I thought I'd do something ridiculous and plot the Super El Niño trend of 2015 forward for Sea Surface Temperatures, see dashed lines in red (2023) and green (2024).

I turns out that we are largely running above that..


The effect of El Niño on the tropical Pacific Sea Surface Temperatures is clearly visible.
Also see the North Pacific and Atlantic:

The anomaly is running off the chart again.

All this extreme ocean surface heat is about to turn into a year of shocking extreme atmospheric temperatures and (even) more extreme weather.

We might be getting a first taste of the Termination Shock from terminating part of our cooling sulphur pollution, while still increasing greenhouse gases.

Also see this long message on how the sun is currently adding to the heat.

And on how greenhouse gases keep the Earth from cooling down.

With some simplified climate energy math.

@d_le_nen The uncertainty is part of the risk:
Read 6 tweets
Aug 8
We have had 36 days in a row of record global surface temperatures.

The 150 days of record ocean surface temperatures are starting to increase atmospheric heat.

Most of the effects of the developing El Niño on global temperatures are still in the pipeline.

Records are being obliterated.

https://t.co/FIYBNqrUyz https://t.co/EEHBpL4usXclimatereanalyzer.org/clim/t2_daily/

Read 7 tweets
Jul 31
We are getting a rough look at what the (ab)normal climate of the 2030s will be like.

A single month might even break through +2.0°C https://t.co/8QcM0JlTbN
See this quick and dirty extrapolation I made last month. July surpassed this.

We might not even need a Super El Niño with the effects of IMO 2020 ship desulphurisation; strong solar activity (11-year cycle) and Hunga Tonga adding to the GHG warming.

The 2015-2016 El Niño introduced global temperatures never observed before.

The 2023-2024 El Niño will do the same.


Read 4 tweets
Jul 28

The Earth's Energy Imbalance from NASA satellite data reached 1.97 W/m² (12-month mean)!!

I called this the most important graph in the world.

This helps to explain all the records currently being broken around the word!

1/ https://t.co/m39mATEupatwitter.com/i/web/status/1…
@NASA Two years ago @NASA and @NOAA published a paper (Norman Loeb et al. 2021) that the rate of global heat uptake had doubled since 2005 up to 2019:

@NASA @NOAA They estimated that the Earth's Energy Imbalance would decrease with La Niña and a negative PDO.

The opposite happened.


Read 11 tweets

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