Planetary Inferno: Nero fiddles while Rome burns

[Think. Again.]

Arctic News
by Andrew Glikson
July 20, 2023

Full article: https://arctic-news.blogspot.com/2023/07/planetary-inferno-nero-fiddles-while-rome-burns.html?m=1

The fast rise in global warming manifested by current extreme weather events betrays a dangerous underestimation of the Earth’s liveable climate, while governments ignore climate science, claim to set limits on domestic emissions, but allow major export of fossil fuels and emissions worldwide on a scale threatening life on Earth. With current policies, there appear to exist few limits on global carbon emissions, as reported by Rogner (1997): “The global fossil resource base is abundant and is estimated at approximately 5000 Gt (billion tons). Compared to current global primary energy use of some 10 Gt per year, this amount is certainly sufficient to fuel the world economy through the twenty-first century”. According to these estimates, future production of coal, oil and gas render a mass extinction of advanced species more than likely. https://archive.is/rHmMR

A significant fraction of carbon gases released from combustion of fossil fuels on timescales of a few centuries remains in the atmosphere as well as leads to acidification of the oceans at a rate faster than its removal by weathering processes and deposition of carbonates. Common measures of the atmospheric lifetime of CO₂ disregard the long time tail of its dissipation, which underestimates the longevity of anthropogenic global warming. Models agree 20–35% of the CO₂ remains in the atmosphere after equilibration with the ocean (over 2–20 centuries). Neutralization by CaCO₃ draws the airborne fraction down further on timescales of 3 to 7 kyr.

With atmospheric CO₂ levels reaching 423 parts per million, according to James Hansen and colleagues humanity is facing a new Frontier, marked by intense heatwaves, more than vindicating warnings by climate scientists over the last 40 years or so. Within less than a century, the levels of CO₂ and temperatures have risen to levels of the Miocene (23.03–5.33 million years ago), with implications for sea level rise (Spratt, 2023). Hominids, living during glacial to inter-glacial periods, rarely had to endure mean temperatures higher than 50°C, which are increasingly common at present. Governments, busy subsidizing new coal mines and oil and gas wells and arming to the teeth for nuclear war, appear to be oblivious to the lessons of the last great world wars.


Figure 1. Global temperature anomalies relative to 1880-1920. Accelerated warming rate are 0.36°C and 0.27°C per decade. Super-El-Niño, projected for 2023, occurs at +0.8 to +1.2 temperature. (Hansen et al., 2023, The climate dice).

No longer does climate change represent a future scenario debated by scientists or deniers, but it constitutes an accelerating reality (Figures 1 and 2) related to the latitudinal shift of climate zones, including expansion of the tropics into temperate regions, Europe and north America. The weakening of the circum-polar jet stream allows heat cells to penetrate polar latitudes and cold fronts to enter high latitude zones. The consequences are represented by accumulation of ice melt water off Greenland and parts of the circum-Antarctic ocean (Figure 2). Increased evaporation over land masses results in draughts, while evaporation from warming oceans gives rise to major floods over large continental regions.


Figure 2. June 2023 global surface temperature anomaly (°C) relative to 1951-1980 June mean. Note the major high latitude temperature anomalies reaching 3 – 4°C above the 1951-1980 June mean. (Hansen et al., 2023, The climate dice).

Full article: https://arctic-news.blogspot.com/2023/07/planetary-inferno-nero-fiddles-while-rome-burns.html?m=1

[OKIsItJustMe]

1. Related communications from James Hansen et al

El Nino and Global Warming Acceleration
The Climate Dice are Loaded. Now, a New Frontier?

Read the next paper (still in review): Global warming in the pipeline

Meanwhile, climate science has exposed a crisis that the world is loath to appreciate. IPCC, the scientific body advising the world on climate, does not bluntly inform the world that the present “wishful thinking” geopolitical approach will be disastrous for today’s young people and their children. Political leaders profess ambitions for dubious net-zero emissions while fossil fuel extraction expands. The only IPCC scenarios that phase down human-made climate change amount to “a miracle will occur.” The one IPCC scenario that moves rapidly to negative global emissions has biomass-burning powerplants that capture and sequester CO₂, a nature-ravaging proposition without scientific and engineering credibility and without a realistic chance of being deployed at scale and on time to address the climate threat.

[Swede]

2. The naysayers of today will be dead.

Their children will watch the world burn.

[Think. Again.]

3. I'm beginning to think...

...that it all might happen faster than that.

[OKIsItJustMe]

4. Nature: Earlier collapse of Anthropocene ecosystems driven by multiple faster and noisier drivers

Earlier collapse of Anthropocene ecosystems driven by multiple faster and noisier drivers

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.

Main
For many observers, UK Chief Scientist John Beddington’s argument that the world faced a ‘perfect storm’ of global events by 20301 has now become a prescient warning. Recent mention of ‘ghastly futures’, ‘widespread ecosystem collapse’ and ‘domino effects on sustainability goals’ tap into a growing consensus within some scientific communities that the Earth is rapidly destabilizing through ‘cascades of collapse’. Some even speculate on ‘end-of-world’ scenarios involving transgressing planetary boundaries (climate, freshwater and ocean acidification), accelerating reinforcing (positive) feedback mechanisms and multiplicative stresses. Prudent risk management clearly requires consideration of the factors that may lead to these bad-to-worst-case scenarios. Put simply, the choices we make about ecosystems and landscape management can accelerate change unexpectedly.

The potential for rapid destabilization of Earth’s ecosystems is, in part, supported by observational evidence for increasing rates of change in key drivers and interactions between systems at the global scale (Supplementary Introduction). For example, despite decreases in global birth rates and increases in renewable energy generation, the general trends of population, greenhouse gas concentrations and economic drivers (such as gross domestic product) are upwards—often with acceleration through the twentieth and twenty-first centuries. Similar non-stationary trends for ecosystem degradation imply that unstable subsystems are common. Furthermore, there is strong evidence globally for the increased frequency and magnitude of erratic events, such as heatwaves and precipitation extremes. Examples include the sequence of European summer droughts since 2015, fire-promoting phases of the tropical Pacific and Indian ocean variability and regional flooding, already implicated in reduced crop yields and increased fatalities and normalized financial costs.

The increased frequency and magnitude of erratic events is expected to continue throughout the twenty-first century. The Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report concludes that ‘multiple climate hazards will occur simultaneously, and multiple climatic and non-climatic risks will interact, resulting in compounding overall risk and risks cascading across sectors and regions’. Overall, global warming will increase the frequency of unprecedented extreme events, raise the probability of compound events and ultimately could combine to make multiple system failures more likely. For example, there is a risk that many tipping points can be triggered within the Paris Agreement range of 1.5 to 2 °C warming, including collapse of the Greenland and West Antarctic ice sheets, die-off of low-latitude coral reefs and widespread abrupt permafrost thaw. These tipping points are contentious and with low likelihood in absolute terms but with potentially large impacts should they occur. In evaluating models of real-world systems, we therefore need to be careful that we capture complex feedback networks and the effects of multiple drivers of change that may act either antagonistically or synergistically. Prompted by these ideas and findings, we use computer simulation models based on four real-world ecosystems to explore how the impacts of multiple growing stresses from human activities, global warming and more interactions between systems could shorten the time left before some of the world’s ecosystems may collapse.

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[OKIsItJustMe]

5. Wikipedia: Planetary Boundaries

Planetary boundaries

Planetary boundaries are a framework to describe limits to the impacts of human activities on the Earth system. Beyond these limits, the environment may not be able to self-regulate anymore. This would mean the Earth system would leave the period of stability of the Holocene, in which human society developed. Crossing a planetary boundary comes at the risk of abrupt environmental change. The framework is based on scientific evidence that human actions, especially those of industrialized societies since the Industrial Revolution, have become the main driver of global environmental change. According to the framework, "transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental-scale to planetary-scale systems.
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Planetary boundaries diagram; orange sections indicate "overshoot" of boundaries, green sections indicate a "safe" state within the boundaries (data for November 2022).

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