Archive for the ‘Ocean dynamics’ Category

Arctic sea ice [image credit: cbc.ca]


The researchers find ‘a significantly declining AA effect on the millennial time scale’ — but then attempt to link that to anthropogenic forcing in recent times, according to the article at least. That seems illogical if the argument is that humans are playing a part. In any case if the effect has been shown to occur over at least a millennium, that in itself casts doubt on claims that humans must be the prime (or any) cause of the most recent observed changes.
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The recent amplified warming in the Arctic during the last decades has received much attention, says Phys.org.

But how Arctic amplification (AA) has varied on longer time scales and what drives these variations remain unclear.

Recently, a study has provided a new perspective on the AA effect during the past millennium based on the best available paleoclimate data and novel data assimilation methods.

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A portion of the Atlantic meridional overturning circulation [image credit: R. Curry, Woods Hole Oceanographic Institution @ Wikipedia]


Another supposed climate tipping point, popular with the alarm-loving media, floats away? A feature that’s “built into many models” was found not to work as advertised.
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Most simulations of our climate’s future may be overly sensitive to Arctic ice melt as a cause of abrupt changes in ocean circulation, according to new research led by scientists at the University of Wisconsin–Madison.

Climate scientists count the Atlantic Meridional Overturning Circulation (or AMOC) among the biggest tipping points on the way to a planetary climate disaster, says Phys.org.

The Atlantic Ocean current acts like a conveyor belt carrying warm tropical surface water north and cooler, heavier deeper water south.

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The signal that wasn’t found could be ‘masked’, researchers suggest. They expected ‘ongoing climate change’ to do something, but maybe it just wasn’t there? Cue more research.
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A new Met Office-led study – reviewing evidence from previous scientific papers and climate models – reveals natural patterns of weakening and strengthening of ocean currents which influence the UK’s weather and climate.

In the North Atlantic lies one of the world’s largest climate mechanisms: a system of currents transporting relatively warm water from the tropics to the poles, with return currents at depth transporting colder, denser water further south.

The transport of heat to the North Atlantic keeps the UK’s climate warmer than other locations at our latitude, says the Met Office.

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According to NOAA’s ENSO blog triple dip La Ninas are now on the menu of imminent possibilities.

Science Matters

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The post below updates the UAH record of air temperatures over land and ocean.  But as an overview consider how recent rapid cooling has now completely overcome the warming from the last 3 El Ninos (1998, 2010 and 2016).  The UAH record shows that the effects of the last one were gone as of April 2021, again in November, 2021 and now in January and February 2022. (UAH baseline is now 1991-2020).

For reference I added an overlay of CO2 annual concentrations as measured at Mauna Loa.  While temperatures fluctuated up and down ending flat, CO2 went up steadily by ~55 ppm, a 15% increase.

Furthermore, going back to previous warmings prior to the satellite record shows that the entire rise of 0.8C since 1947 is due to oceanic, not human activity.

gmt-warming-events

The animation is an update of a previous analysis from Dr. Murry Salby.  These graphs use Hadcrut4 and…

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Arctic sea ice [image credit: cbc.ca]


One finding was that snow cover variability was more ‘extreme’ than expected, pointing to the need for further research as well as improvements to climate models. Whether the recent Arctic weather/climate history is a reliable guide to future conditions remains to be seen.
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Hundreds of international researchers are currently analyzing observations from the one-year MOSAiC expedition, during which hundreds of environmental parameters were recorded with unprecedented accuracy and frequency over a full annual cycle in the Central Arctic Ocean, says Phys.org.

They have now published three overview articles on the MOSAiC atmosphere, snow and sea ice, and ocean programs in the journal Elementa, highlighting the importance of examining all components of the climate system together.

These results present the first complete picture of the climate processes in the central Arctic which is warming more than two times as fast as the rest of the planet—processes which affect weather and climate worldwide.

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Opposite sea ice trends? [Credits: NASA Goddard Space Flight Center/Joy Ng]


Climate modellers need yet more and bigger computers to stand a chance of eradicating faulty sea ice projections in the polar regions, apparently. Meanwhile, they believe there must be some ‘delay’ in their long-predicted but not (yet?) happening Antarctic sea ice decline. Quote: “Our study supports the hypothesis that climate models and projections of the Antarctic sea ice will be far more reliable as soon as they are capable of realistically simulating a high-resolution ocean, complete with eddies”.
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Despite global warming and the sea-ice loss in the Arctic, the Antarctic sea-ice extent has remained largely unchanged since 1979, says Eurekalert.

However, existing climate model-based simulations indicate significant sea-ice loss, contrary to actual observations.

As experts from the Alfred Wegener Institute have now shown, the ocean may weaken warming around Antarctica and delay sea-ice retreat.

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Antarctica


A key sentence to note in this report says: ‘Half of all carbon dioxide bound in the world’s oceans is found in the Southern Ocean.’ What impact does the outgassing have on the total carbon dioxide content of the atmosphere, which we’re expected to believe is a matter of huge climate concern requiring drastic and expensive measures for decades to come?
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Storms over the waters around Antarctica drive an outgassing of carbon dioxide into the atmosphere, according to a new international study with researchers from the University of Gothenburg. — Phys.org reporting.

The research group used advanced ocean robots for the study, which provides a better understanding of climate change and can lead to better global climate models.

The world’s southernmost ocean, the Southern Ocean that surrounds Antarctica, plays an important role in the global climate because its waters contain large amounts of carbon dioxide.

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Bioluminescence [image credit: Gov’t. of South Australia]


Such events happen because ‘the microbes can suddenly light up as if a switch were thrown’. Even the smallest occurrence can be ‘100 times larger than Manhattan’.
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The ocean has always glowed, says the NY Times (via bdnews24.com).

The Greeks and Romans knew of luminous sea creatures as well as the more general phenomenon of seawater that can light up in bluish-green colours.

Charles Darwin, as he sailed near South America on a dark night aboard the HMS Beagle, encountered luminescent waves. He called it “a wonderful and most beautiful spectacle.”

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This won’t exactly be music to the ears of the climate alarmist tendency, which prefers to claim that people somehow dictate the course of climate variations.
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The Sun’s energy affects our climate but its influence is often ignored as changes in its intensity are very small. Its effect might be subtle but over decadal periods it adds up to being significant as a series of recent papers show, says Net Zero Watch.

Scientists from the University of California, Irvine, the National Taiwan Normal University, and the Institute of Atmospheric Physics, of the Chinese Academy of Sciences, Beijing, find that the 11-year solar cycle has a significant correlation with sea surface temperature variations in the North-eastern Pacific.

They believe that the Sun’s influence is first seen and then amplified in the lower stratosphere, but it then alters the circulation in the troposphere which then affects the temperature of the ocean.

They note that the changes have a structure similar to that of the Pacific meridional mode – an interaction between trade winds and ocean evaporation which is an important trigger of the central Pacific (CP) type of the El Niño-Southern Oscillation (ENSO).

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A portion of the Atlantic meridional overturning circulation [image credit: R. Curry, Woods Hole Oceanographic Institution @ Wikipedia]


This article starts off confident that the researchers are right – ‘we now know’ etc. – but later retreats and says ‘the cooling appears to have’ etc. But as the Little Ice Age is an interesting topic it’s worth a look.
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New research from the University of Massachusetts Amherst provides a novel answer to one of the persistent questions in historical climatology, environmental history and the earth sciences: what caused the Little Ice Age?

The answer, we now know, is a paradox: warming, says Phys.org.

The Little Ice Age was one of the coldest periods of the past 10,000 years, a period of cooling that was particularly pronounced in the North Atlantic region.

This cold spell, whose precise timeline scholars debate, but which seems to have set in around 600 years ago, was responsible for crop failures, famines and pandemics throughout Europe, resulting in misery and death for millions.

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The ocean carbon cycle [credit: IAEA]


Having much better information about how nature’s carbon cycle is working, before attempting to apply random expensive schemes of uncertain impact to try and alter it, would surely be a sound approach, as the researchers suggest. Surprises might not be welcome ones.
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The Southern Ocean is a significant carbon sink says Phys.org, absorbing a large amount of the excess carbon dioxide emitted into the atmosphere by human activities, according to a new study led by the National Center for Atmospheric Research (NCAR).

The findings provide clarity about the role the icy waters surrounding Antarctica play in buffering the impact of increasing greenhouse gas emissions, after research published in recent years suggested the Southern Ocean might be less of a sink than previously thought.

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Fram Strait is the only deep passage between the Arctic and World Oceans [credit: Bdushaw @ Wikipedia]


Twenty six ‘COP’s and much of the world still claims to believe in, and frames its energy and various other policies according to, flawed climate models? If ‘rapid’ Arctic warming was already happening 120 years ago at an early stage of industrialisation what was, or were, the cause(s)?
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The Arctic Ocean has been getting warmer since the beginning of the 20th century – decades earlier than records suggest – due to warmer water flowing into the delicate polar ecosystem from the Atlantic Ocean.

An international group of researchers reconstructed the recent history of ocean warming at the gateway to the Arctic Ocean in a region called the Fram Strait, between Greenland and Svalbard, says SciTech Daily.

Using the chemical signatures found in marine microorganisms, the researchers found that the Arctic Ocean began warming rapidly at the beginning of the last century as warmer and saltier waters flowed in from the Atlantic – a phenomenon called Atlantification – and that this change likely preceded the warming documented by modern instrumental measurements.

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Credit: NOAA

Researchers propose another weather/climate cycle.
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A team of researchers with members affiliated with a large number of institutions across Japan has found that the Gulf stream and Kuroshio are synchronized on a decadal time scale, says Phys.org.

In their paper published in the journal Science, the group describes their study of decades of weather satellite data and the link between the two ocean currents.

Paola Cessi, with the Scripps Institution of Oceanography at the University of California, has published a Perspective piece on the work done by the team in Japan in the same journal issue.

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Halfway through this article we see the study’s findings were made ‘where increases in sea surface temperatures have been recorded because of the reversal of a climatic condition called the Pacific Decadal Oscillation, with likely connections to global climate change’. So the PDO has changed, which it regularly will do as its name (‘decadal’) indicates, and they want to tie the consequences to humans? That seems to be implied, although left vague by the usual catch-all term ‘climate change’.
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WASHINGTON—Warming ocean waters have caused a drop in the brightness of the Earth, according to a new study, says Eurekalert.

Researchers used decades of measurements of earthshine — the light reflected from Earth that illuminates the surface of the Moon to find that there has been a significant drop in Earth’s reflectance over the past two decades.

The Earth is now reflecting about half a watt less light per square meter than it was 20 years ago, with most of the drop occurring in the last three years of earthshine data, according to the new study in the AGU journal Geophysical Research Letters, which publishes high-impact, short-format reports with immediate implications spanning all Earth and space sciences.

That’s the equivalent of 0.5% decrease in the Earth’s reflectance. Earth reflects about 30% of the sunlight that shines on it.

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ENSO1

Credit: concernusa.org

A key premise of most computer models seems to be that the atmosphere, with its 0.04% CO2 content, drives ocean temperatures. As most of the energy is in the oceans, why wouldn’t it be the other way round?
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The cycling between warm El Niño and cold La Niña conditions in the eastern Pacific (commonly referred to as the El Niño-Southern Oscillation, ENSO) has persisted without major interruptions for at least the last 11,000 years, says Phys.org.

This may change in the future according to a new study published in the journal Nature Climate Change by a team of scientists from the IBS Center for Climate Physics (ICCP) at Pusan National University in South Korea, the Max Planck Institute of Meteorology, Hamburg, Germany, and the University of Hawaiʻi at Mānoa, U.S.

The team conducted a series of global climate model simulations with an unprecedented spatial resolution of 10 km in the ocean and 25 km in the atmosphere.

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AMOC_circ

A portion of the Atlantic meridional overturning circulation [image credit: R. Curry, Woods Hole Oceanographic Institution @ Wikipedia]

Widely differing climate models are supposed to be a reliable guide to the future? Clearly not. Here the uncertainty gets investigated, and pinned on a phenomenon that was recently claimed by Mann et al not to exist. Of course all these models make the assumption that carbon dioxide at a tiny 0.04% of the atmosphere is a key variable of concern, despite all the other variability in the climate system that they have to wrestle with.
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Thirty state-of-the-art IPCC-climate models predict dramatically different climates for the Northern Hemisphere, especially Europe, says Phys.org.

An analysis of the range of responses now reveals that the differences are mostly down to the individual model’s simulations of changes to the North Atlantic ocean currents and not only—as normally assumed—atmospheric changes.

The work, by Katinka Bellomo, National Research Council of Italy, Institute of Atmospheric Sciences and Climate, and colleagues is published today in Nature Communications and is part of the European science collaboration, TiPES, coordinated by the University of Copenhagen.

All climate models vary in the details. Variables such as atmospheric pressure, cloud cover, temperature gradients, sea surface temperatures, and many more are tuned to interact slightly differently for every model. This means that the predictions of the many models also vary.

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The ocean carbon cycle [credit: IAEA]

Proving once again how massively important carbon dioxide is to nature, via photosynthesis.
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Tiny algae in Earth’s oceans and lakes take in sunlight and carbon dioxide and turn them into sugars that sustain the rest of the aquatic food web, gobbling up about as much carbon as all the world’s trees and plants combined, says Phys.org.

New research shows a crucial piece has been missing from the conventional explanation for what happens between this first “fixing” of CO2 into phytoplankton and its eventual release to the atmosphere or descent to depths where it no longer contributes to global warming. [Talkshop comment – evidence-free assertion.]

The missing piece? Fungus.

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atlantic1

Credit: NASA – GISS

They refer here to the same AMOC that was recently claimed by Mann et al to be of no significance, or even not to exist at all. But empirical evidence has its uses.
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From 50,000 to 15,000 years ago, during the last ice age, Earth’s climate wobbled between cooler and warmer periods punctuated by occasional, dramatic ice-melting events, says Phys.org.

Previous research has suggested that these oscillations were likely influenced by changes in the Atlantic Meridional Overturning Circulation (AMOC), a pattern of currents that carry warm, tropical water to the North Atlantic, where it cools, sinks, and flows back south. However, the precise role played by the AMOC in ancient climate fluctuations has been unclear.

Now Toucanne et al. have reconstructed the historical flow of a key current in the upper part (the northward flow) of the AMOC, the Glacial Eastern Boundary Current (GEBC), shedding new light on how the AMOC can drive sudden changes in climate.

The GEBC flowed northward along Europe’s continental margin during the last ice age (it persists today as the European Slope Current). To better understand the GEBC’s role in the AMOC, the researchers collected six seafloor sediment cores off the coast of France.

Analysis of grain sizes and isotope levels in the core layers revealed the current’s strength when each layer was deposited, yielding the first high-resolution, 50,000-year historical record of the current.

This new historical record shows that the GEBC flowed faster during warmer intervals of the last ice age but weakened during the coldest periods.

The timing of these changes aligns well with previously established records on AMOC speed and the southward return flow of deep waters to the west.

Comparing the history of the GEBC with other records also shows that major ice-melting events, in which ice age glaciers released huge amounts of freshwater into the Atlantic, correspond with periodic weakening of the current and of the AMOC in general.

Full article here.

ocean_co2

The ocean carbon cycle [credit: IAEA]

Quoting from the article: ‘The main reason for this is global warming, which leads to a decrease in the solubility of gases and thus also of oxygen.’ Surely the same applies to carbon dioxide (CO2): warmer water causes release of some of it from the oceans into the atmosphere? Diagrams of the Earth’s natural carbon cycle seem conclusive enough.
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The life of almost all animals in the ocean depends on the availability of oxygen, which is dissolved as a gas in seawater, says Phys.org.

However, the ocean has been continuously losing oxygen for several decades. In the last 50 years, the loss of oxygen accumulates globally to about 2% of the total inventory (regionally sometimes significantly more).

The main reason for this is global warming, which leads to a decrease in the solubility of gases and thus also of oxygen, as well as to a slowdown in the ocean circulation and vertical mixing.

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Canceling the AMO

Posted: March 7, 2021 by oldbrew in Critique, modelling, Natural Variation, Ocean dynamics
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‘So, what exactly is wrong with Mann’s analysis? He relies on global climate models, which are inadequate in simulating the AMO.’
‘Not at all convincing’…

Climate Etc.

by Judith Curry

Conclusion from Michael Mann’s new paper:  “We conclude that there is no compelling evidence for internal multidecadal oscillations in the climate system.”

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