Monday, August 5, 2024

Sulfur Makes and Sulfur Takes


You can't make it up - the pollution that's been part of the climate change problem, is also part of the solution to the climate change problem. 

And even better, literally see use of the word "Termination Shock" in the wild:

Reduced sulfur content in shipping fuel associated with increased maritime atmospheric warming
May 2024, phys.org

The International Maritime Organization's 2020 regulation (IMO 2020) reduced the maximum sulfur content allowed in shipping fuel from 3.5% to 0.5% to help reduce air pollution, but they also cool the Earth's surface in two ways by directly reflecting sunlight back to space and by affecting cloud cover.

They calculated the effect of IMO 2020 on the atmospheric levels of sulfate aerosols over the ocean and how this affected cloud composition, and found substantial reductions in both the levels of atmospheric aerosols and the cloud droplet number density, with the greatest reductions in the North Atlantic, the Caribbean Sea, and the South China Sea - the regions with the busiest shipping lanes. 

Then they estimated the effect of IMO 2020 on Earth's energy budget since 2020, and calculated that the estimated effect is equivalent to 80% of the observed increase in the heat energy retained on Earth over that period.

The authors suggest that the substantial modeled effect of IMO 2020 on Earth's energy budget demonstrates the potential effectiveness of marine cloud brightening as a strategy to temporarily cool the climate. However, they also warn that the intended reduction in sulfur dioxide emissions due to IMO 2020 potentially causing an inadvertent increase in marine atmospheric temperature is an example of a geoengineering termination shock, which could affect regional weather patterns.

via University of Maryland Sciences and Exploration Directorate, Goddard Space Flight Center: Tianle Yuan, Abrupt reduction in shipping emission as an inadvertent geoengineering termination shock produces substantial radiative warming, Communications Earth & Environment (2024). DOI: 10.1038/s43247-024-01442-3.



Computer models show heat waves in north Pacific may be due to China reducing aerosols
May 2024, phys.org

The research team noted that the onset of the heat waves appeared to follow successful efforts by the Chinese government to reduce aerosol emissions from their country's factories. Beginning around 2010, factories and power generating plants in China began dramatically reducing emissions of aerosols such as sulfate, resulting in much cleaner air.

The models also showed why - as less heat was reflected back into space over China, warming of coastal regions in Asia began, resulting in the development of high-pressure systems. That in turn made low-pressure systems in the middle Pacific more intense. And that resulted in the Aleutian Low growing bigger and moving south which weakened the westerly winds that typically cool the sea surface. The result was hotter conditions.

via Ocean University of China: Hai Wang et al, Atmosphere teleconnections from abatement of China aerosol emissions exacerbate Northeast Pacific warm blob events, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2313797121


Marine cloud brightening models show unexpected consequences of geoengineering
Jun 2024, phys.org

Here for the lexcion:
Marine Cloud Brightening (MCB) - injecting massive amounts of sea salt into the lower atmosphere to serve as tiny mirrors, bouncing heat and light from the sun back out into space.

The work involved configuring established climate models to show what would happen if artificial stratocumulus clouds were created under two different scenarios, both over the North Pacific: one over the temperate latitudes and the other over sub-tropical waters. Under both scenarios, the artificial clouds were generated and maintained for nine months every year for 30 years.

The researchers found that the artificial clouds would reduce temperatures in the western U.S., primarily California - reducing risk of dangerously high temperatures by as much as 55%. But they also found the same clouds would reduce rainfall amounts, both in the U.S. and other parts of the world.

The research team also found that if the MCB project continued to the year 2050, its benefits would taper off and heat waves in Europe would become much more common, showing that engineering projects can lead to unforeseen consequences in other parts of the world.

via University of California San Diego and the National Center for Atmospheric Research: Jessica S. Wan et al, Diminished efficacy of regional marine cloud brightening in a warmer world, Nature Climate Change (2024). DOI: 10.1038/s41558-024-02046-7


We have been very busy:
Climate engineering off US coast could increase heatwaves in Europe
Jun 2024, The Guardian

The recent sharp rise in global temperatures has prompted some research institutions and private organisations to engage in geoengineering research that used to be virtually taboo.

In Australia, scientists have been trialling marine cloud brightening strategies for at least four years to try to cool the Great Barrier Reef and slow its bleaching.

“There is really no solar geoengineering governance right now"
--Jessica Wan, UC San Diego’s Scripps Institution of Oceanography

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