Abstract

Potential climate-related impacts on future crop yield are a major societal concern. Previous projections of the Agricultural Model Intercomparison and Improvement Project’s Global Gridded Crop Model Intercomparison based on the Coupled Model Intercomparison Project Phase 5 identified substantial climate impacts on all major crops, but associated uncertainties were substantial. Here we report new twenty-first-century projections using ensembles of latest-generation crop and climate models. Results suggest markedly more pessimistic yield responses for maize, soybean and rice compared to the original ensemble. Mean end-of-century maize productivity is shifted from +5% to −6% (SSP126) and from +1% to −24% (SSP585)—explained by warmer climate projections and improved crop model sensitivities. In contrast, wheat shows stronger gains (+9% shifted to +18%, SSP585), linked to higher CO2 concentrations and expanded high-latitude gains. The ‘emergence’ of climate impacts consistently occurs earlier in the new projections—before 2040 for several main producing regions. While future yield estimates remain uncertain, these results suggest that major breadbasket regions will face distinct anthropogenic climatic risks sooner than previously anticipated.

Abstract

In this chapter we apply the concepts of resilience theory and systemic risk to the Bronze Age Collapse. We contend that this was a case of synchronous failures driven by both long-term trends in interconnectedness and inequality, as well as external shocks such as climate change, warfare (including from hostile migration), rebellion, and earthquakes. This set off a chain reaction as the loss of key cities destabilised the trade-network and undermined state revenue, leading to further rebellion, migration, and warfare. Eventually, enough cities were destroyed to undermine the economic, cultural, and political fabric that held the Bronze Age together. Many states recovered and displayed resilience through the Bronze Age systems collapse. No two states were alike in their resilience. The Neo-Assyrians persisted by moving from a strategy of trade to conquest. The surviving Hittites in northern Syria, in contrast, relied on the modularity of their semi-feudal structure. Systemic risk and resilience are helpful lens for viewing the Bronze Age collapse and recovery, as well as taking lessons for the modern globalised world. It at least provides historical grounds for believing that synchronous failures can happen and can be lethal to states.

Abstract

The Ancestral Puebloans occupied Chaco Canyon, in what is now the southwestern USA, for more than a millennium and harvested useful timber and fuel from the trees of distant forests as well as local woodlands, especially juniper and pinyon pine. These pinyon juniper woodland products were an essential part of the resource base from Late Archaic times (3000–100 BC) to the Bonito phase (AD 800–1140) during the great florescence of Chacoan culture. During this vast expanse of time, the availability of portions of the woodland declined. We posit, based on pollen and macrobotanical remains, that the Chaco Canyon woodlands were substantially impacted during Late Archaic to Basketmaker II times (100 BC–AD 500) when agriculture became a major means of food production and the manufacture of pottery was introduced into the canyon. By the time of the Bonito phase, the local woodlands, especially the juniper component, had been decimated by centuries of continuous extraction of a slow-growing resource. The destabilizing impact resulting from recurrent woodland harvesting likely contributed to the environmental unpredictability and difficulty in procuring essential resources suffered by the Ancestral Puebloans prior to their ultimate departure from Chaco Canyon.

Abstract

There is increasing concern that the Atlantic Meridional Overturning Circulation (AMOC) may collapse this century with a disrupting societal impact on large parts of the world. Preliminary estimates of the probability of such an AMOC collapse have so far been based on conceptual models and statistical analyses of proxy data. Here, we provide observationally based estimates of such probabilities from reanalysis data. We first identify optimal observation regions of an AMOC collapse from a recent global climate model simulation. Salinity data near the southern boundary of the Atlantic turn out to be optimal to provide estimates of the time of the AMOC collapse in this model. Based on the reanalysis products, we next determine probability density functions of the AMOC collapse time. The collapse time is estimated between 2037-2064 (10-90% CI) with a mean of 2050 and the probability of an AMOC collapse before the year 2050 is estimated to be 59±17%.

Abstract

Under current emission trajectories, temporarily overshooting the Paris global warming limit of 1.5 °C is a distinct possibility. Permanently exceeding this limit would substantially increase the probability of triggering climate tipping elements. Here, we investigate the tipping risks associated with several policy-relevant future emission scenarios, using a stylised Earth system model of four interconnected climate tipping elements. We show that following current policies this century would commit to a 45% tipping risk by 2300 (median, 10–90% range: 23–71%), even if temperatures are brought back to below 1.5 °C. We find that tipping risk by 2300 increases with every additional 0.1 °C of overshoot above 1.5 °C and strongly accelerates for peak warming above 2.0 °C. Achieving and maintaining at least net zero greenhouse gas emissions by 2100 is paramount to minimise tipping risk in the long term. Our results underscore that stringent emission reductions in the current decade are critical for planetary stability.

cross-posted from: https://lemmy.world/post/18232700

Study has found that the lake, which has lost 73% of its water, released climate-warming emissions

cross-posted from: https://lemmy.world/post/18192844

Ground temperatures across great swathes of the ice sheets of Antarctica have soared an average of 10C above normal over the past month, in what has been described as a near record heatwave.

While temperatures remain below zero on the polar land mass, which is shrouded in darkness at this time of year, the depths of southern hemisphere winter, temperatures have reportedly reached 28C above expectations on some days.

The globe has experienced 12 months of record warmth, with temperatures consistently exceeding the 1.5C rise above preindustrial levels that has been touted as the limit to avoiding the worst of climate breakdown.

Abstract

Researchers have argued that wealthy nations rely on a large net appropriation of labour and resources from the rest of the world through unequal exchange in international trade and global commodity chains. Here we assess this empirically by measuring flows of embodied labour in the world economy from 1995–2021, accounting for skill levels, sectors and wages. We find that, in 2021, the economies of the global North net-appropriated 826 billion hours of embodied labour from the global South, across all skill levels and sectors. The wage value of this net-appropriated labour was equivalent to €16.9 trillion in Northern prices, accounting for skill level. This appropriation roughly doubles the labour that is available for Northern consumption but drains the South of productive capacity that could be used instead for local human needs and development. Unequal exchange is understood to be driven in part by systematic wage inequalities. We find Southern wages are 87–95% lower than Northern wages for work of equal skill. While Southern workers contribute 90% of the labour that powers the world economy, they receive only 21% of global income.

About this book

In this updated edition of a groundbreaking text, concepts such as energy return on investment (EROI) provide powerful insights into the real balance sheets that drive our “petroleum economy.” Hall and Klitgaard explore the relation between energy and the wealth explosion of the 20th century, and the interaction of internal limits to growth found in the investment process and rising inequality with the biophysical limits posed by finite energy resources. The authors focus attention on the failure of markets to recognize or efficiently allocate diminishing resources, the economic consequences of peak oil, the high cost and relatively low EROI of finding and exploiting new oil fields, including the much ballyhooed shale plays and oil sands, and whether alternative energy technologies such as wind and solar power can meet the minimum EROI requirements needed to run society as we know it.

For the past 150 years, economics has been treated as a social science in which economies are modeled as a circular flow of income between producers and consumers. In this “perpetual motion” of interactions between firms that produce and households that consume, little or no accounting is given of the flow of energy and materials from the environment and back again. In the standard economic model, energy and matter are completely recycled in these transactions, and economic activity is seemingly exempt from the Second Law of Thermodynamics. As we enter the second half of the age of oil, when energy supplies and the environmental impacts of energy production and consumption are likely to constrain economic growth, this exemption should be considered illusory at best. This book is an essential read for all scientists and economists who have recognized the urgent need for a more scientific, empirical, and unified approach to economics in an energy-constrained world, and serves as an ideal teaching text for the growing number of courses, such as the authors’ own, onthe role of energy in society.

Abstract

We calculate the climate forcing for the 2 ys after the 15 January 2022, Hunga Tonga-Hunga Ha'apai (Hunga) eruption. We use satellite observations of stratospheric aerosols, trace gases and temperatures to compute the tropopause radiative flux changes relative to climatology. Overall, the net downward radiative flux decreased compared to climatology. The Hunga stratospheric water vapor anomaly initially increases the downward infrared radiative flux, but this forcing diminishes as the anomaly disperses. The Hunga aerosols cause a solar flux reduction that dominates the net flux change over most of the 2 yrs period. Hunga induced temperature changes produce a decrease in downward long-wave flux. Hunga induced ozone reduction increases the short-wave downward flux creating small sub-tropical increase in total flux from mid-2022 to 2023. By the end of 2023, most of the Hunga induced radiative forcing changes have disappeared. There is some disagreement in the satellite measured stratospheric aerosol optical depth (SAOD) observations which we view as a measure of the uncertainty; however, the SAOD uncertainty does not alter our conclusion that, overall, aerosols dominate the radiative flux changes.

Key Points

The 15 Jan. 2022, Hunga eruption increased aerosols and H2O in the southern hemisphere stratosphere and then dispersed throughout 2022/3

Stratospheric water vapor, ozone, temperature, and aerosol optical depth contribute to the change in downward radiative fluxes

Hunga produced a global decrease in radiative of less than ∼0.25 W/m2 over the 2 yrs period

Full toot:

When I talk about capitalism collapsing under the weight of the climate catastrophe, I mean things like this:

“Insurers providing policies to homeowners were hit with a $15.2 billion net underwriting loss last year, according to figures from rating agency AM Best, saying that the figure was the worst since at least 2000 and more than double the losses since the previous year.”

https://www.reuters.com/business/finance/us-home-insurers-suffer-biggest-loss-century-2023-ft-says-2024-07-28/

Summary

Regional climate strongly regulates the occurrence of wildfires partly because drying of fuel load increases fires. The large amounts of aerosols released by wildfires can also strongly affect regional climate. Here we show positive feedback (a seasonal burned area enhancement of 7–17%) due to wildfire aerosol forcing in Africa found in the simulations using the interactive REgion-Specific ecosystem feedback Fire (RESFire) model in the Community Earth System Model (CESM). The positive feedback results partly from the transport of fire aerosols from burning (dry) to wet regions, reducing precipitation and drying fuel load to enhance fires toward the non-burning (wet) region. This internally self-enhanced burning is an important mechanism for the regulation of African ecosystems and for understanding African fire behaviors in a changing climate. A similar mechanism may also help sustain wildfires in other tropical regions.

Extract

John Lie’s most recent publication delves into the economic, political, and social changes that have taken place in Japan in the four decades since the bursting of the country’s economic bubble, and the values and practices of earlier eras that have resurfaced in this age of limits. These values include the so-called artisanal ethos and the ordinary pleasures of everyday life, exemplified in the book by practices such as sushi-making or hot spring bathing that date back at least to the Edo period, but also by the leisure-oriented lives of the contemporary otaku. The author’s main argument is that these values and practices may help us envision a more humane and sustainable future in the face of the crumbling promises of economic growth that have led to rising inequality and environmental devastation worldwide.

The focus on Japan is not only a logical consequence of the author’s scholarly career, but also particularly pertinent as the country is at the forefront of some of the major challenges facing other advanced industrial societies, such as population aging and economic stagnation. Moreover, Japan’s struggle to define its identity between “East” and “West,” reflected in the various political projects described in the early chapters of the book, also means that premodern values and practices thrive and coexist with more Westernized ways of living, thinking, and being. Enriched by an acute and broad historical perspective (and imagination) painfully lacking in much of the sociological research on contemporary Japan, the author avoids essentialist descriptions of Japanese culture and grand narratives by making a strong case for the historicity of each practice, including recent reconstructions, reinterpretations, and expansions from elite to popular practices (or vice versa, as in the case of sushi-eating) in the modern era.

Abstract

Anthropogenic methane (CH4) emissions increases from the period 1850–1900 until 2019 are responsible for around 65% as much warming as carbon dioxide (CO2) has caused to date, and large reductions in methane emissions are required to limit global warming to 1.5°C or 2°C. However, methane emissions have been increasing rapidly since ~2006. This study shows that emissions are expected to continue to increase over the remainder of the 2020s if no greater action is taken and that increases in atmospheric methane are thus far outpacing projected growth rates. This increase has important implications for reaching net zero CO2 targets: every 50 Mt CH4 of the sustained large cuts envisioned under low-warming scenarios that are not realized would eliminate about 150 Gt of the remaining CO2 budget. Targeted methane reductions are therefore a critical component alongside decarbonization to minimize global warming. We describe additional linkages between methane mitigation options and CO2, especially via land use, as well as their respective climate impacts and associated metrics. We explain why a net zero target specifically for methane is neither necessary nor plausible. Analyses show where reductions are most feasible at the national and sectoral levels given limited resources, for example, to meet the Global Methane Pledge target, but they also reveal large uncertainties. Despite these uncertainties, many mitigation costs are clearly low relative to real-world financial instruments and very low compared with methane damage estimates, but legally binding regulations and methane pricing are needed to meet climate goals.

Pesticides are an essential feature of modern-day agriculture that adds to the list of factors that increase cancer risk. Our study aims to comprehensively evaluate this relationship through a population-based approach that considers confounding variables such as county-specific rates of smoking, socioeconomic vulnerability, and agricultural land. We achieved our goal with the implementation of latent-class pesticide use patterns, which were further modeled among covariates to evaluate their associations with cancer risk. Our findings demonstrated an association between pesticide use and increased incidence of leukemia; non-Hodgkin's lymphoma; bladder, colon, lung, and pancreatic cancer; and all cancers combined that are comparable to smoking for some cancer types. Through our comprehensive analysis and unique approach, our study emphasizes the importance of a holistic assessment of the risks of pesticide use for communities, which may be used to impact future policies regarding pesticides.