collapse

Abstract

The dynamics of atmospheric CO2 concentrations during and following the last deglaciation have mainly been ascribed to carbon release from and uptake in oceans, primarily in the Southern Ocean. But recent studies also point toward a terrestrial influence. We quantify dynamic changes to northern terrestrial carbon stocks from the Last Glacial Maximum (21,000 years) until present at millennial time steps using a combination of paleo-data and climate-biome modeling. During the deglaciation, northern land carbon storage declined by >300 petagrams of carbon with a minimum around 11,000 years, followed by progressively higher land carbon stocks during the Holocene. We find evidence that dynamic changes in terrestrial land carbon stocks were of a scale to exert large influence on atmospheric CO2 concentrations and that postglacial terrestrial carbon stock dynamics were dominated by losses from permafrost-affected loess and gains into peatlands.

Scientists say ‘shocking’ discovery shows rapid cuts in carbon emissions are needed to avoid catastrophic fallout

Zero chance of that happening /s

Climate models recently indicated that a collapse before 2100 was unlikely but the new analysis examined models that were run for longer, to 2300 and 2500. These show the tipping point that makes an Amoc shutdown inevitable is likely to be passed within a few decades, but that the collapse itself may not happen until 50 to 100 years later.

Abstract

The occurrence and fate of microplastics in forest ecosystems is a recognized knowledge gap. In this paper, we used an aligned extraction method to quantify microplastics (>20 µm) in organic and mineral forest soil horizons and throughfall deposition. Calculation of forest soil microplastic stocks and throughfall fluxes allowed an estimation of throughfall contribution to microplastic accumulation in forest soils back to 1950. We identified a short-term microplastic enrichment in decomposed litter horizons followed by an accumulation in lower mineral soil caused by litter turnover processes. Similar microplastic features in soil and throughfall deposition indicate that microplastics entering forest soils primarily originate from atmospheric deposition and litter fall, while other sources have a minor impact. We conclude that forests are good indicators for atmospheric microplastic pollution and that high microplastic concentrations in forest soils indicate a high diffuse input of microplastics into these ecosystems.

Continual Cascading Consequences from Chaotic Climate Catastrophes in our Climate Casino

After my last few videos on the abrupt regime change loss of Antarctic Sea Ice, many people have asked me about the consequences to humanity.

This video is my answer. I find the reality profound, and profoundly disturbing for humanity. Abrupt Climate System Mayhem in almost real time...

I chat about as many of the complexities of this regime change to our overall climate system, and then to certain regions.

I also chat about what has happened in the past when the AMOC (Atlantic Meridional Overturning Circulation) has shut down. The most recent AMOC shutdown was 8,200 years ago when an ice dam in Canada broke, releasing vast amounts of water from Lake Agassiz into the North Atlantic Ocean, shutting down the AMOC for about 160 years.

This is fitting, as the site where I filmed this video is an archaeological dig in Lake Leamy Park in Quebec along the Ottawa River. This location was submerged by Lake Agassiz, and when the lake drained this land was uncovered, having previously been scoured by the Laurentide Ice sheet covering Canada.

Arrowheads found on the site date back to 6,000 years, and the site has pretty much been occupied since then. Many artifacts dating back 1,000 to 2,000 years are commonly found by the public during their digs.

Emerging evidence also shows that the AOC (Antarctic Overturning Circulation) has fluctuated greatly during previous ice ages, but this data is more sparse than what we have for the Arctic.

I don't want to spill all the beans here in my video description, so you will just have to watch my entire video.

Buckle your seatbelts...

Links:

National Capital Commission (NCC) Public Archeological Digs: https://ncc-ccn.gc.ca/events/public-archaeological-digs

Leamy Lake Park https://ncc-ccn.gc.ca/places/leamy-lake-park

Article from last year: Archaeological digs in the Ottawa region draw a lot of attention https://www.aptnnews.ca/national-news/archaeological-digs-in-the-ottawa-region-draw-a-lot-of-attention/

CBC National Broadcaster article from last year: Climate change, eroding shorelines and the race against time to save Indigenous history: Archaeologists, Indigenous communities forced into difficult choices about which historical sites to save https://www.cbc.ca/news/canada/ottawa/climate-change-archaeology-saving-artifacts-1.7308384

NCC Report on climate change risks, including risks to archeological sites along the Ottawa River: Climate Change Vulnerability & Risk Assessment https://ncc-website-2.s3.amazonaws.com/documents/Climate-Vulnerability-Risk-Assessment.pdf

Link to video… https://youtu.be/YNFYZ9bzJfQ

Abstract

The Atlantic meridional overturning circulation (AMOC) is an important tipping element in the climate system. There is a large uncertainty whether the AMOC will start to collapse during the century under future climate change, as this requires long climate model simulations which are not always available. Here, we analyze targeted climate model simulations done with the Community Earth System Model (CESM) with the aim to develop a physics-based indicator for the onset of an AMOC tipping event. This indicator is diagnosed from the surface buoyancy fluxes over the North Atlantic Ocean and is performing successfully under quasi-equilibrium freshwater forcing, freshwater pulse forcing, climate change scenarios, and for different climate models. An analysis consisting of 25 different climate models shows that the AMOC could begin to collapse by 2063 (from 2026 to 2095, to percentiles) under an intermediate emission scenario (SSP2-4.5), or by 2055 (from 2023 to 2076, to percentiles) under a high-end emission scenario (SSP5-8.5). When the AMOC collapses, the Northwestern European climate changes drastically and this will likely induce severe societal impacts.

Plain Language Summary

There is a growing risk that the Atlantic meridional overturning circulation (AMOC) collapses to a significantly weaker state under climate change. This AMOC tipping event causes a substantial shift of the global climate. It is therefore important to assess the risk of such an event under future climate change, but this requires long climate model simulations which are not always available. We developed a robust indicator that accurately predicts the onset of an AMOC tipping event and works under different forcing configurations and for different climate model simulations. Under a high-emission scenario (SSP5-8.5), the likelihood of an AMOC tipping event occurring in the century is high and reduces for lower emission scenarios (SSP2-4.5). If the AMOC starts to collapse, it takes more than 100 years to reach a substantially weaker state. During that transition, the Northwestern European climate would change drastically and is expected to see colder winters, less rainfall, and more severe winter storms.

Key Points

Multiple AMOC collapses are simulated in the CESM under transient climate change scenarios

A physics-based indicator derived from surface buoyancy fluxes is proposed for the onset of an AMOC collapse under transient forcing

The indicator is successfully performing in CESM freshwater pulse and climate change simulations, including CMIP6 under climate change

Abstract

The Pacific decadal oscillation (PDO)—the leading pattern of climate variability driving changes over the North Pacific and surrounding continents—is now thought to be generated by processes internal to the climate system1,2. According to this paradigm, the characteristic, irregular oscillations of the PDO arise from a collection of mechanisms involving ocean and atmosphere interactions in the North and tropical Pacific3,4,5. Recent variations in the coupled ocean–atmosphere system, such as the 2015 El Niño, ought to have shifted the PDO into its positive phase6. Yet, the PDO has been locked in a consistent downward trend for more than three decades, remanding nearby regions to a steady set of climate impacts. Here we show that the main multidecadal variations in the PDO index during the twentieth century, including the ongoing, decades-long negative trend, were largely driven by human emissions of aerosols and greenhouse gases rather than internal processes. This anthropogenic influence was previously undetected because the current generation of climate models systematically underestimate the amplitude of forced climate variability. A new attribution technique that statistically corrects for this error suggests that observed PDO impacts—including the ongoing multidecadal drought in the western United States—can be largely attributed to human activity through externally forced changes in the PDO. These results indicate that we need to rethink the attribution and projection of multidecadal changes in regional climate.

Abstract

The widespread prevalence of plastics and in particular, microplastics (MPs) raises concerns about their potential toxic effects. MPs, defined as particles smaller than 5 mm, are distributed throughout ecosystem and can enter the human body through the food chain. There is a lack of knowledge regarding MP potential harmful effects on the mammal’s body, especially the brain. This study aimed to examine the impact of low-density polyethylene (LDPE) MPs (< 30 μm) on blood–brain barrier (BBB) integrity, oxidative stress, and neuronal health. Male rats were exposed to LDPE MPs via oral administration for 3 and 6 weeks. The results revealed no significant changes in brain water content across groups. However, BBB integrity was significantly compromised after both 3 and 6 weeks of exposure. Oxidative stress increased in MP-treated groups, evidenced by decreased superoxide dismutase (SOD) levels and elevated malondialdehyde (MDA). Additionally, brain-derived neurotrophic factor (BDNF) levels significantly declined in the 6-week group. Histological analysis indicated neuronal damage and death in both treatment durations. These findings demonstrate that chronic exposure to LDPE MPs impairs BBB integrity, increases oxidative stress, and induces neuronal damage in rats. The results highlight the neurotoxic potential of MPs and emphasize the need for further research to address their possible health risks.

cross-posted from: https://sh.itjust.works/post/44697420

A scientist has made the shocking claim that there's a 49% chance the world will end in just 25 years. Jared Diamond, American scientist and historian, predicted civilisation could collapse by 2050. He told Intelligencer: "I would estimate the chances are about 49% that the world as we know it will collapse by about 2050."

Diamond explained that fisheries and farms across the globe are being "managed unsustainably", causing resources to be depleted at an alarming rate. He added: "At the rate we’re going now, resources that are essential for complex societies are being managed unsustainably. Fisheries around the world, most fisheries are being managed unsustainably, and they’re getting depleted.

"Farms around the world, most farms are being managed unsustainably. Soil, topsoil around the world. Fresh water around the world is being managed unsustainably."

The Pulitzer Prize winning author warned that we must come up with more sustainable practices by 2050, "or it'll be too late".

Summary

Background

Fine particulate matter (PM2·5) from wildfire smoke could be more harmful to human health than that from other sources. Evidence of the short-term association between wildfire-related PM2·5 and mortality in Europe remains sparse, leading to uncertainties in the fire-related PM2·5 mortality burden.

Methods

In this retrospective, multicountry epidemiological study, we used the EARLY-ADAPT database to obtain daily mortality records in 654 contiguous subnational regions from 32 European countries, representing a population of 541 million individuals. We combined these data with daily estimates of fire-related and non-fire-related PM2·5 from the System for Integrated Modelling of Atmospheric Composition model during 2004–22. Regional and pooled associations between daily fire-related PM2·5 and all-cause and cause-specific mortality were quantified using quasi-Poisson regression. We compared deaths attributable to fire-related PM2·5 using relative risks (RRs) specific to fire-related PM2·5 versus total PM2·5.

Findings

Our study data included 95⸱3 million daily deaths for all-cause mortality, 19⸱5 million daily deaths for cardiovascular mortality, and 3⸱9 million daily deaths for respiratory mortality from Jan 1, 2004, until the latest available year in each country. Pooled cumulative (lags 0–7) RRs associated with a 1 μg per m3 increase in fire-related PM2·5 were 1⸱007 (95% CI 1⸱004–1⸱010) for all-cause mortality, 1⸱009 (1⸱006–1⸱013) for cardiovascular mortality, and 1⸱013 (1⸱008–1⸱019) for respiratory mortality. RRs were larger for fire-related PM2·5 than for non-fire-related PM2·5. Using RRs for total (fire-related and non-fire-related) PM2·5 underestimated the fire-related PM2·5 attributable mortality by 93%.

Interpretation

Associations with all-cause and cause-specific mortality were larger for fire-related compared with non-fire-related PM2·5. Assuming wildfire PM2·5 has the same effect as total PM2·5 substantially underestimates the mortality burden of wildfire smoke.

Abstract

Human-caused climate change worsens with every increment of additional warming, although some impacts can develop abruptly. The potential for abrupt changes is far less understood in the Antarctic compared with the Arctic, but evidence is emerging for rapid, interacting and sometimes self-perpetuating changes in the Antarctic environment. A regime shift has reduced Antarctic sea-ice extent far below its natural variability of past centuries, and in some respects is more abrupt, non-linear and potentially irreversible than Arctic sea-ice loss. A marked slowdown in Antarctic Overturning Circulation is expected to intensify this century and may be faster than the anticipated Atlantic Meridional Overturning Circulation slowdown. The tipping point for unstoppable ice loss from the West Antarctic Ice Sheet could be exceeded even under best-case CO2 emission reduction pathways, potentially initiating global tipping cascades. Regime shifts are occurring in Antarctic and Southern Ocean biological systems through habitat transformation or exceedance of physiological thresholds, and compounding breeding failures are increasing extinction risk. Amplifying feedbacks are common between these abrupt changes in the Antarctic environment, and stabilizing Earth’s climate with minimal overshoot of 1.5 °C will be imperative alongside global adaptation measures to minimise and prepare for the far-reaching impacts of Antarctic and Southern Ocean abrupt changes.

Churning quantities of carbon dioxide into the atmosphere at the rate we are going could lead the planet to another great dying

Worryingly, in the past few decades geologists have discovered that many, if not most, of the mass extinctions of Earth history – including the very worst ever by far – were caused not by asteroids as they had expected, but by continent-spanning volcanic eruptions that injected catastrophic amounts of CO2 into the air and oceans.