August 2023

1.   Ecological tipping points could occur much sooner than expected

Simon Willcock et al., “Earlier collapse of Anthropocene ecosystems driven by multiple faster and noisier drivers,” Nature Sustainability (22 June 2023).  bit.ly/46zM3zx

Abstract:  A major concern for the world’s ecosystems is the possibility of collapse, where landscapes and the societies they support change abruptly. Accelerating stress levels, increasing frequencies of extreme events and strengthening intersystem connections suggest that conventional modelling approaches based on incremental changes in a single stress may provide poor estimates of the impact of climate and human activities on ecosystems. We conduct experiments on four models that simulate abrupt changes in the Chilika lagoon fishery, the Easter Island community, forest dieback and lake water quality—representing ecosystems with a range of anthropogenic interactions. Collapses occur sooner under increasing levels of primary stress but additional stresses and/or the inclusion of noise in all four models bring the collapses substantially closer to today by ~38–81%. We discuss the implications for further research and the need for humanity to be vigilant for signs that ecosystems are degrading even more rapidly than previously thought.

See also, Jonathan Watts, “Ecological tipping points could occur much sooner than expected, study finds:  Amazon rainforest and other ecosystems could collapse ‘very soon’, researchers warn,” The Guardian (22 June 2023). bit.ly/46kQ4ri

2.   Current means of cutting shipping emissions in half

Jasper Faber, Daan van Seters, Peter Scholten, Shipping GHG
emissions 2030: Analysis of the maximum technical abatement potential, CE Delft (June 2023).  bit.ly/3NpQFPK

See also, Fiona Harvey, “Shipping emissions could be halved without damaging trade, research finds,” The Guardian (26 June 2023).  bit.ly/3CNLG6I
“… research published on Monday by the consultancy CE Delft found that shipping could be cut by between a third and a half this decade by using already available techniques and embarking on innovative technology such as hydrogen.

There are ways of using oil-powered ships more efficiently, including better maintenance of engines, cutting speeds slightly or optimising speeds to the sea conditions. Ships can be fitted with modern forms of sails or “wind-assist” technologies that take some of the strain from engines when the wind is strong.

If these were used, and another 5-10% of shipping were to begin to use experimental fuels such as hydrogen, biofuels or forms of electrification with solar batteries, then emissions from fuel use could be cut by between 36% and 47% within the next decade, compared with 2008 levels.”

3.  Low emission zones improving health

Rosemary C. Chamberlain et al. “Health effects of low emission and congestion charging zones: a systematic review,” Lancet (July 2023).  bit.ly/3XBUg1U

See also,  Gary Fuller, “Low emission zones are improving health, studies show,” The Guardian (30 June 2023).   bit.ly/44nb1zY

“LEZs are not the same everywhere, making them hard to compare. Some apply to lorries and buses only, while others also include taxis, cars and motorcycles. The health researchers in each country also used different approaches and different data sources. The studies compared data before and after the LEZ start date and some also made comparisons with areas with no LEZ. Data came from health survey results, GP and hospital records, and death registrations.

Despite these differences in approach, five of the eight LEZ studies showed a clear reduction in heart and circulatory problems when an LEZ was implemented. These included fewer admissions to hospital, fewer deaths from heart attacks and strokes, and fewer people with blood pressure problems. These results came from zones in Germany, Japan and the UK. One of the German studies analysed hospital data from 69 cities with LEZs. It found a 2%-3% reduction in heart problems and 7%-12% reduction in stroke. The improvements were greatest for older people and resulted in estimated health cost savings of €4.4bn (£3.8bn).

Not all studies found the same results. Five studies, again covering zones in Germany, Japan and the UK, looked at breathing and lung problems. Two found improvements and the remainder showed no definite result. None showed a clear deterioration.”

4.  For every degree Fahrenheit the world warms, extreme rainfall at higher elevation increases by 8.3%

Mohmmmed Ombadi et al., “A warming-induced reduction in snow fraction amplifies rainfall extremes,” Nature (28 June 2023).  go.nature.com/3r8Xr50

Abstract:  The intensity of extreme precipitation events is projected to increase in a warmer climate1,2,3,4,5, posing a great challenge to water sustainability in natural and built environments. Of particular importance are rainfall (liquid precipitation) extremes owing to their instantaneous triggering of runoff and association with floods6, landslides7,8,9 and soil erosion10,11. However, so far, the body of literature on intensification of precipitation extremes has not examined the extremes of precipitation phase separately, namely liquid versus solid precipitation. Here we show that the increase in rainfall extremes in high-elevation regions of the Northern Hemisphere is amplified, averaging 15 per cent per degree Celsius of warming—double the rate expected from increases in atmospheric water vapour. We utilize both a climate reanalysis dataset and future model projections to show that the amplified increase is due to a warming-induced shift from snow to rain. Furthermore, we demonstrate that intermodel uncertainty in projections of rainfall extremes can be appreciably explained by changes in snow–rain partitioning (coefficient of determination 0.47). Our findings pinpoint high-altitude regions as ‘hotspots’ that are vulnerable to future risk of extreme-rainfall-related hazards, thereby requiring robust climate adaptation plans to alleviate potential risk. Moreover, our results offer a pathway towards reducing model uncertainty in projections of rainfall extremes.

See also, AP, “Global heating making extreme rain and catastrophic flooding more likely,” The Guardian (28 June 2023).  bit.ly/448B5zg:  Study finds extreme rainfall at higher elevations increases by 8.3% for every degree Fahrenheit world warms

5.  US plans for tracking emissions from agriculture

U. S. Dept of Agriculture press release on “New Investments to Improve Measurement, Monitoring, Reporting and Verification of Greenhouse Gas Emissions”   bit.ly/3Ogx0Ce
The U.S. Department of Agriculture (USDA) will invest $300 million to improve measurement, monitoring, reporting and verification of greenhouse gas emissions and carbon sequestration in climate-smart agriculture and forestry.  The new investments is made possible by the Inflation Reduction Act, which provided nearly $20 billion in overall investments to advance climate-smart agriculture and forestry practices with the goal of achieving a 50-52 percent reduction in greenhouse gas emissions by 2030, compared to 2005 levels…

This new funding and strategy will turbocharge development of the data, science, and technology innovation to address the crisis at hand and unlock the full economic opportunity for our country by improving national greenhouse gas estimates in the agriculture and forestry sectors and making these climate solutions more investment-ready for the private sector…

To carry out these tasks, USDA has identified seven key focus areas that reflect the framework outlined by the federal strategy and are based on substantial input from stakeholders:

Establish and advance a Soil Carbon Monitoring and Research Network with a perennial biomass component;
Establish and advance a Greenhouse Gas Research Network;
Expand data management, infrastructure and capacity;
Improve models and tools for assessing greenhouse gas outcomes at operational, state, regional, and national scales;
Improve NRCS conservation practice standards and implementation data to reflect greenhouse gas mitigation opportunities;
Improve temporal and spatial coverage of national conservation activity data; and
Strengthen the Greenhouse Gas Inventory and Assessment Program of USDA

See also, Linda Qiu, “U.S. to Track Emissions From Agriculture,” The New York Times (13 July 2023).

6.   Underground climate change below big cities

Alessandro F. Rotta Loria, “The silent impact of underground climate change on civil infrastructure,” Communications Engineering (11 July 2023). bit.ly/3qdXIDt

Abstract:  Urban areas increasingly suffer from subsurface heat islands: an underground climate change responsible for environmental, public health, and transportation issues. Soils, rocks, and construction materials deform under the influence of temperature variations and excessive deformations can affect the performance of civil infrastructure. Here I explore if ground deformations caused by subsurface heat islands might affect civil infrastructure. The Chicago Loop district is used as a case study. A 3-D computer model informed by data collected via a network of temperature sensors is used to characterize the ground temperature variations, deformations, and displacements caused by underground climate change. These deformations and displacements are significant and, on a case-by-case basis, may be incompatible with the operational requirements of civil structures. Therefore, the impact of underground climate change on civil infrastructure should be considered in future urban planning strategies to avoid possible structural damage and malfunction. Overall, this work suggests that underground climate change can represent a silent hazard for civil infrastructure in the Chicago Loop and other urban areas worldwide, but also an opportunity to reutilize or minimize waste heat in the ground.

See also, Raymond Zhong and Jamie Kelter Davis, “Study Details the Climate Change Down Below,“ The New York Times (12 July 2023).

7.  Sharp weakening or even shutdown of AMOC sooner than expected?

Peter Ditlevsen and Susanne Ditlevsen, “Warning of a forthcoming collapse of the Atlantic meridional overturning circulation,” Nature Communications (25 July 2023). go.nature.com/44IrfEv
Abstract:  The Atlantic meridional overturning circulation (AMOC) is a major tipping element in the climate system and a future collapse would have severe impacts on the climate in the North Atlantic region. In recent years weakening in circulation has been reported, but assessments by the Intergovernmental Panel on Climate Change (IPCC), based on the Climate Model Intercomparison Project (CMIP) model simulations suggest that a full collapse is unlikely within the 21st century. Tipping to an undesired state in the climate is, however, a growing concern with increasing greenhouse gas concentrations. Predictions based on observations rely on detecting early-warning signals, primarily an increase in variance (loss of resilience) and increased autocorrelation (critical slowing down), which have recently been reported for the AMOC. Here we provide statistical significance and data-driven estimators for the time of tipping. We estimate a collapse of the AMOC to occur around mid-century under the current scenario of future emissions.

See also, Raymond Zhong, “Atlantic Nears ‘Tipping Point,’ Scientists Say,”  The New York Times (26 July 2023).

8.  Greenland’s ice sheet is less stable than we thought

Andrew J. Christ, et al., “Deglaciation of northwestern Greenland during Marine Isotope Stage 11,” Science (20 July 2023). bit.ly/3ObFs5N

Editor’s summary
Measurements made on subglacial sediment from the Camp Century ice core in northwestern Greenland show that the location was ice free during the interglacial that occurred around 400,000 years ago. Christ et al. used luminescence dating and cosmogenic nuclide data to show that the sediment was deposited under ice-free conditions after having been exposed at the surface to sunlight fewer than 16,000 years earlier. The absence of ice at that location means that the Greenland Ice Sheet must have contributed more than 1.4 meters of sea-level equivalent to the high sea-level stand, when the average global air temperature was similar to what we will soon experience because of human-caused climate warming. —H. Jesse Smith

9.  Early arctic spring has been replaced by seasonal extremes

Niels Martin Schmidt, et al., “Little directional change in the timing of Arctic spring phenology over the past 25 years,” Current Biology (26 Juily 2023). bit.ly/3QhCgbn

See also,. Ludia Larsen, “On the Coast of Greenland, Early Arctic Spring Has Been Replaced by Seasonal Extremes, New Research Shows.  In assembling data over 25 years, scientists found plants and animals reaching the limits of their ability to respond to climate variability,” Inside Climate News (26 July 2023).  bit.ly/3Qb9Rns

In a paper published in 2007, based on data from the 1990s, scientists analyzed a decade of phenological measurements and found that arctic springs were beginning earlier on the coast of northeast Greenland. The rising temperatures and earlier snowmelt drove back the time that plants and animals started to emerge and arrive after winter.

New research published recently looks at the full 25 years of phenological data, covering a period from 1996 to 2020. The results indicate that this previously reported pattern is all but nonexistent. The study determined, instead, that earlier arctic springs are being replaced by extreme yearly variability in the timing of physical and biological measurements.

Evidence suggests that many organisms in this arctic environment are reaching the limit of their ability to respond to climate variability. The different species often rely on each other for survival so changes in the timing of different seasonal events could steer organisms off track, leading to an ecological network out of sync with itself, the research suggests.

10.  Extreme heat in July 2023 made much more likely by climate change

“Extreme heat in North America, Europe and China in July 2023 made much more likely by climate change,” World Weather Attribution (25 July 2023).  bit.ly/44LYEOx

Scientists from the World Weather Attribution initiative collaborated to assess to what extent human-induced climate change altered the likelihood and intensity of the extreme July heat in these three regions.

Using published peer-reviewed methods, we analysed how human-induced climate change altered the likelihood and intensity of 1) 18-day average maximum temperatures over the most affected regions in western US, Texas and northern Mexico; 2) 7-day average maximum temperatures over land in the rectangular box(5W-25E, 36-45N) covering the most affected region; 3) 14-day average maximum temperatures over the lowlands of China, again covering the most affected region.   [See graphs in original]

Several Main Findings:

In line with what has been expected from past climate projections and IPCC reports these events are not rare anymore today. North America, Europe and China have experienced heatwaves increasingly frequently over the last years as a result of warming caused by human activities, hence the current heat waves are not rare in today’s climate with an event like the currently expected approximately once every 15 years in the US/Mexico region, once every 10 years in Southern Europe, and once in 5 years for China.

Without human induced climate change these heat events would however have been extremely rare. In China it would have been about a 1 in 250 year event while maximum heat like in July 2023 would have been virtually impossible to occur in the US/Mexico region and Southern Europe if humans had not warmed the planet by burning fossil fuels.

In all the regions a heatwave of the same likelihood as the one observed today would have been significantly cooler in a world without climate change. Similar to previous studies we found that the heatwaves defined above are 2.5°C warmer in Southern Europe, 2°C warmer in North America and about 1°C in China in today’s climate than they would have been if it was not for human-induced climate change.




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