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

1/9🧵 Image
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.

3/9 Image
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).

4/9 Image
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.

5/9 Image
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.

6/9 Image
Differences in forcing estimates are caused by uncertainties in aerosol load, atmospheric lifetime, relative emission of direct SO4, DMS, emission distribution and seasonal variability.

7/9 Image
The past two decades saw an albedo decrease and an increase in planetary heat uptake, coinciding with a decrease in anthropogenic sulfur emissions.

8/9 Image
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.

9/9 Image
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.

11/x Image
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.

12/x Image
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.

13/x ImageImage
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.

14x Image
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.

15/x ImageImageImage
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.

16/x ImageImage
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.

18/ Image
*22.2 million km² that is of course..

• • •

Missing some Tweet in this thread? You can try to force a refresh

Keep Current with Leon Simons

Leon Simons Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!


Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!


0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy


3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us on Twitter!