Month: June 2021

Guest contribution by Eric Worrall

Given the complete lack of problems so far, climate scientists seem to be reinforcing the “woo woo” factor in forecasted climate disasters. But they don’t add a fixed timescale and refuse to label their warnings as “predictions.”

Scientists warn that climate tipping points could collapse like dominoes

The analysis shows a considerable risk of cascade events even with a warming of 2 ° C with serious long-term effects

Damian Carrington
Environment Editor @dpcarrington
Fri 4 Jun 2021 02:34 AEST

Ice sheets and ocean currents that are threatened by climatic tipping points can destabilize each other when the world warms, which, according to a risk analysis, leads to a domino effect with serious consequences for humanity.

Tipping points occur when global warming pushes temperatures above a critical threshold, resulting in accelerated and irreversible effects. It is believed that some large ice sheets in Antarctica have already passed their tipping points, which means that sea levels will rise sharply in the centuries to come.

The new research examined the interactions between ice sheets in West Antarctica, Greenland, the warm Atlantic Gulf Stream, and the Amazon rainforest. The scientists performed 3m Computer simulations and found domino effects in a third of them, even if the temperature rise was below 2 ° C, the upper limit of the Paris Agreement.

…

“We offer a risk analysis, not a prediction, but our results still give cause for concern, ”said Prof. Ricarda Winkelmann from the Potsdam Institute for Climate Impact Research (PIK) in Germany. “[Our findings] could mean that we have less time to reduce greenhouse gas emissions and still prevent tipping processes. “

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“The study suggests that below 2 ° C of global warming – that is, in the target range of the Paris Agreement – there could still be a significant risk of triggering cascading climatic tipping points,” said Lenton. “What the new study doesn’t do is unzip the timescale over which tipping points could change and cascades could unfold – instead, it focuses on the possible consequences. The results should be viewed as ‘commitments’ we may soon make to potentially irreversible changes and cascades, and leave as a grim legacy for future generations. “

…

Read more: https://www.theguardian.com/environment/2021/jun/03/climate-tipping-points-could-topple-like-dominoes-warn-scientists

The abstract of the study;

Interacting tilting elements increase the risk of climatic domino effects in the event of global warming

Nico Wunderling1,2,3, Jonathan F. Donges1,4, Jürgen Kurths1,5, and Ricarda Winkelmann

Received: March 26, 2020 – Discussion started: April 03, 2020 – Revised: March 15, 2021 – Accepted: April 07, 2021 – Published: June 03, 2021

As global warming progresses, the risk increases that one or more tipping elements in the climate system will exceed a critical threshold, which has serious consequences for the global climate, ecosystems and human society. While the underlying processes are pretty well understood, It is unclear how their interactions could affect the overall stability of the Earth’s climate system. This cannot yet be fully analyzed with the most modern earth system models due to computational limitations as well as some missing and insecure process representations of certain tilting elements. Here we explicitly examine the effects of known physical interactions between the ice sheets of Greenland and West Antarctica, the Atlantic Meridional Overturning Circulation (AMOC) and the Amazon rainforest using a conceptual network approach. In equilibrium experiments, we analyze the risk that domino effects will be triggered by each of the individual tipping elements in global warming. In these experiments we propagate the uncertainties in critical temperature thresholds, interaction strengths and interaction structure over large ensembles of simulations in a Monte Carlo approach. Overall, we find that the interactions tend to destabilize the network of tipping elements. In addition, our analysis shows the qualitative role of each of the four tipping elements within the network and shows that the polar ice sheets on Greenland and West Antarctica are often the initiators of tipping cascades, while the AMOC acts as the facilitator of transmission cascades. This indicates that the ice sheets, which are already threatening to exceed their temperature thresholds in the Paris area of ​​1.5 to 2 ° C, are of particular importance for the stability of the entire climate system.

Read more: https://esd.copernicus.org/articles/12/601/2021/

Imagine someone designing a new bridge and the architect admits that due to “missing and uncertain process representations of certain tipping elements” he cannot calculate the stability of the bridge or predict the point in time when predicted events should occur. Would you take this analysis seriously?

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When NASA’s Perseverance rover landed in Jezero Crater on February 18, 2021, it brought an interesting little companion that has been causing a stir lately! We are of course talking about the Ingenuity Mars Helicopter, an experimental flight system that is supposed to show whether air systems can work on Mars. Since its maiden flight on April 19, the helicopter has pushed the boundaries of flight on Mars, flying farther and faster each time.

In fact, the helicopter broke several records during its first five flights, reaching a maximum distance of 266 m (873 ft) in 117 seconds. Unfortunately, Ingenuity’s sixth and final flight didn’t go so well. Due to a navigation timing error, the helicopter lost its trajectory, but was only able to land safely a few meters from its target.

This is the first time Ingenuity has suffered a malfunction since it first ascended to the skies of Mars over six weeks ago. Fortunately, the fail-safe systems prevented accidents and the mission leaders were able to pinpoint the source of the problem. The difficulties began towards the end of the first leg of the sixth test flight of the helicopter, which took place on Saturday, May 22nd, or day 91 of the Perseverance mission (Sol 91).

Long range photo of Ingenuity taken with Perseverance’s SuperCam instrument. Photo credit: NASA / JPL-Caltech / LANL / CNES / IRAP / Kevin M. Gill

According to chief pilot Håvard Grip, who recently wrote about the bug on the mission’s status update page, this flight should shift the flight range even further and demonstrate the helicopter’s aerial photography capabilities before descending at 4 m / s (14.4 km / h; 9 mph) Fly 150 m (492 ft) horizontally southwest.

Once there, it should move west an additional 15 m during the acquisition, then fly an additional 50 m (164 ft) northeast before landing – a total of 215 m (705 ft) round trip.

“The telemetry of flight six shows that the first 150-meter stretch of the flight went smoothly. But towards the end of this section, something happened: Ingenuity began to adjust its speed and lean back and forth in an oscillating pattern. This behavior persisted for the rest of the flight. Before the safe landing, on-board sensors indicated that the rotorcraft was experiencing roll and pitch deflections of more than 20 degrees, large control inputs and peaks in power consumption. “

The problem appears to have been the result of a “bug” in the image pipeline sent from the navigation camera to the navigation system, throwing the timing sequence off track and confusing the vehicle with its location. The navigation camera is one of two used by Ingenuity and is responsible for tracking surface features used by the helicopter’s flight computer to keep the helicopter within its predetermined flight path.

As Ingenuity travels greater distances, more images are needed to track its trajectory and ensure it stays on course. According to chief pilot Havard Grip, this “error” occurred in the pipeline of the images sent by the navigation camera approximately 54 seconds after the flight:

“This bug resulted in a single image being lost, but more importantly, all subsequent navigation images were delivered with inaccurate timestamps. From that point on, every time it made a correction based on a navigation image, the navigation algorithm worked on incorrect information about the time of the shot. The resulting inconsistencies significantly deteriorated the information used to fly the helicopter, resulting in estimates being continually “corrected” to account for phantom errors. Great vibrations followed. “

Fortunately, NASA’s Jet Propulsion Laboratory engineers who built Ingenuity were sure they were adding a large “margin of stability” to the design of the helicopter’s flight control system (so that it can tolerate significant errors without becoming unstable). This kicked in during the flight and allowed Grip and the mission team to safely lower the helicopter just 5 meters (16 feet) from its intended landing site.

In addition, the mission team has a process in place to stop using the navigation camera images during the final phase of the descent and landing. This ensures a smooth and continuous estimation of the movement of the helicopter during this particularly critical phase of flight testing. This practice paid off here as it ensured that by the end of the sixth flight, Ingenuity ignored images with timing errors and could stop oscillating and leveling before touchdown.

Ingenuity’s image was captured by Perseverance’s Mastcam-Z instrument on May 23, 2021 – the day after its sixth flight. Photo credit: NASA / JPL-Caltech / ASU / MSSS

While the flight failed, Grip emphasized that it was demonstrating the effectiveness of the Ingenuity skill and the subsystems that came into play. This included the rotor system, the actuators and the propulsion system of the helicopter, which responded to the increased power requirement caused by the breakdown and kept the helicopter in the air. It was precisely these fail safes that enabled a margin of success in what could otherwise have been a catastrophe.

“Ingenuity literally struggled through the situation, and while the flight uncovered a timing vulnerability that needs to be addressed, it also confirmed the robustness of the system in several ways,” said Grip. “Although we didn’t intentionally plan such a stressful flight, NASA now has flight data that examines the outer reaches of the helicopter’s power range. This data will be carefully analyzed in the coming period and our knowledge base about flying helicopters on Mars will be expanded. “

Two months after the Perseverance rover landed on Mars, Ingenuity became the first aircraft to perform a powered flight on another planet. Originally, the technology demonstrator was only supposed to carry out five test flights over 30 mission days (sols). NASA has been so impressed by the success to date that it has decided to extend its mission by at least a month.

The data collected will feed into future missions to Mars and other non-airless bodies (such as Titan), where aircraft will be able to do science and offer a unique perspective on alien environments. In short, this “little helicopter that could” was nothing if it didn’t have the right name!

Further reading: Phys.org, NASA

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Guest “don’t try not to be picky” by David Middleton

An ancient pulse of meltwater raised the sea level by 18 meters
Meltwater pulse 1A, a period of rapid sea level rise after the last deglaciation, was driven by melting ice from North America and Scandinavia, according to new research.

By Tim Hornyak 24 hours ago

The period in which the sea level shot up at the end of the last ice age about 14,600 years ago is known as meltwater pulse 1A (MWP-1A). Since this pulse was identified from coral records in 1989, the origin of the meltwater has been controversial. Some researchers have hypothesized that Antarctica was the main source of the meltwater, while other scientists suggest it came from the northern hemisphere.

A new study by Nature Communications concluded that melting ice sheets in North America, followed by Scandinavia, were the dominant driving forces for MWP-1A, and that the global mean sea level rise over 500 years was 17.9 meters.

[…]

Eos

The Climatariat has been desperate to blame Meltwater Pulse 1A for the instability of the Antarctic Sea Ice Cliffs (MICI) since it was first identified in 1989, right after Al Gore invented global warming. Their figurehead for this phenomenon was the Greenland glacier Jakobshavn Isbrae, which suddenly stopped cooperating in 2016. The climatariat quickly changed the chicken little cackling of “Run Away! The glaciers are shrinking! ”Run away! The glaciers are growing! “

The paper, Lin et al., 2021, supports the obvious explanation of Meltwater Pulse 1A.

Figure 1. Deglaciation from the late Pleistocene to the early Holocene. (State Museum Illinois)

The full text of the paper is available and worth reading. The Eos article, on the other hand …

Meltwater pulse 1A, a time of rapid sea level rise after the last deglaciation …

Eos

Meltwater Pulse 1A (MWP 1A) occurred relatively early during the last deglaciation, not after.

Figure 2. Global increase in seal level during the Holocene transgression. MWP 1A occurred at ~ 14.6 kya. Note that the error bar is ± 12 meters.
(Siddall et al., 2003)

Then there was the mandatory and free …

Insights into climate change today
Yusuke Yokoyama, a professor at the Atmosphere and Ocean Research Institute at the University of Tokyo who was not involved in the study, said the new research is a possible answer to the question of meltwater sources for MWP-1A, but the debate is far from over .

Eos

The main criterion of the “not participating in the study” professor was the choice of the radiometric dating method … At no point in time has a contribution to the article provided “Insights into climate change today” because there are none.

References

Hornyak, T. (2021), An old meltwater pulse raised the sea level by 18 meters, Eos, 102, https://doi.org/10.1029/2021EO159031. Published on June 2nd, 2021.

Lin, Y., Hibbert, FD, Whitehouse, PL et al. A fine-tuned solution from Meltwater Pulse 1A sources using fingerprints at sea level. Nat Commun 12, 2015 (2021). https://doi.org/10.1038/s41467-021-21990-y

Siddall M, Rohling EJ, Almogi-Labin A, Hemleben C, Meischner D, Smelzer I, Smeed DA (2003). “Sea level fluctuations during the last ice age cycle”. Nature 423: 853-858

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