Blistering heat waves across the Southern Hemisphere, strange storms in the North. Alex reports new science of Atmospheric Rivers, Arctic Ice and teleconnections. Columbian scientist Paola Arias Gomez explains continuing drought & record heat smashing agriculture in Argentina, South Brazil, and Uruguay – another hit for world food prices. Plus Greta Thunberg reads from her latest: “The Climate Book”.

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You know those atmospheric rivers that drowned California? In astounding science, Dr. Pengfei Zhang and colleagues find those airborne torrents are reaching all the way to the Arctic Sea. They weaken Arctic ice in the winter, and that changes weather all over the Northern Hemisphere. Why, and how does it work?

There is more.

Atmospheric rivers are increasing as the world warms, and their impacts add more warming again.

Arctic ice in winter has become an important place. In 2007, September sea ice was reduced by tens of thousands of square kilometers or square miles. Sea ice went even lower in 2012. Millions of people are worried about the low state of summer sea ice – but now we find winter ice is not forming as before. The winter sea ice drops rapidly when an atmospheric river arrives, leaving a damaged ice-pack, much weaker as it goes into the next summer melt. This paper verifies that is happening.

We also learn more about the strange phenomenon of teleconnection. Scientists, sometimes aided by deep-learning computers, can wade through vast amounts of collected data to see patterns that seem connected, even though they are half a world away. For example, satellite data might shows when the winter sea ice is weaker, rainfall in central China changes.  Further down, I have more new science from Chinese scientists about this case.

In a teleconnection, scientists compare the two events on graphs. They go up and down together. This is teleconnection. It does not by itself say that one phenomenon causes the other. It only says they move together. Many cases of teleconnection have been discovered. It shows how complex and inter-related this planetary system is.


This paper by Zhang and colleagues also points again to possibilities of abrupt climate change. As co-author L. Ruby Leung said in a press release:

We often think that Arctic sea ice decline is a gradual process due to gradual forcings like global warming. This study is important in that it finds sea ice decline is due to episodic extreme weather events — atmospheric rivers…

“Episodic extreme weather events”. Remember those words. Instead of the gradual warming and rising seas projected by older science, and repeated in the media, a growing chorus of established scientists are returning to the idea of abrupt climate change. A new regime of floods in one region, or drought in another, could pop up in a year or two – and never go back. There are multiple cases from the deep past showing these irreversible events happen. It re-writes ideas of “preparedness” and certainly the risks.

In 2014, Obama’s Science Advisor John Holdren called for an end to “climate change”. Dr. Holdren said we should use the words “climate disruption” instead. This past winter was certainly that for weather in the United States, as it was in the UK a few years ago. Storm after storm arrived with strangely mild weather in between. Nothing was stable.

There could be a hidden twist: one of these weather episodes might kick large changes, in circulation in the atmosphere and ocean. We might arrive in a new hotter state filled with difficult surprises. For example, the late and great American scientist Stephen Schneider gave a presentation in 2002. It was titled “Abrupt Non-Linear Climate Change, Irreversibility and Surprise”. More on that to come.


So we begin with the paper “More frequent atmospheric rivers slow the seasonal recovery of Arctic sea ice”. All in all, I spoke with the lead author, Pengfei Zhang. He is Assistant Research Professor of Atmospheric Science, at Penn State University. Pengfei specializes in connections between the upper atmosphere and weather down here. He led a number of articles on Arctic, sea ice, and extreme weather in various parts of the world. Then I began the adventure of reading the new paper in-depth along with some of the science it builds on, plus a few articles, press releases, and videos.

There is so much in this research. Let’s take it in order: the atmospheric rivers, then the winter sea ice, followed by what this all means for billions of humans north of the equator.

Zhang et al say Atmospheric Rivers are “long, narrow transient corridors of strong horizontal moisture transport, typically accompanied by a low-level jet ahead of an extratropical cyclone.” Those are the cyclones, also called hurricanes or typhoons, that sometimes strike heavily populated countries, often causing large-scale death and damages. Not all hurricanes have Atmospheric Rivers, Zhang told me, but 82% of ARs are associated with an an extra-tropical storm. With Atmospheric Rivers, storms and record-breaking rainfall generally come together.

So Atmospheric Rivers are bands of water-laden air. They generally form as the sun’s heat strikes the ocean around the Equator. The hotter air holds more moisture, about 7% more for each degree of average global temperature rise. Some of these sky rivers flow in a kind of belt across the world, watering South America and the jungles of Africa, and Asia. The new paper says: “In recent decades, more frequent ARs have been observed in Greenland and West Antarctica, coinciding with the poleward shift of ARs in a warming climate. This study reports an increased AR frequency over the sea-ice-covered Eurasian Arctic.

The equatorial band of moisture can divide and flow northward. An arm of heavy winds and water arrived in California for example, as the extreme flooding event of December 2022. Some go to Canada’s West Coast. Atmospheric Rivers, or AR for short, can even reach the Poles, hitting both Antarctica and the Arctic. This group of scientists chose a relatively well-studied part of the Arctic Ocean. Called “ABK” this is the ocean north of both Norway and Russia. The Barents Sea and the Kara Sea are included.


Why do scientists look there? Pengfei Zhang cited three reasons:

1. The sea ice variability and change(decline) is the largest in Arctic, indicating its sensitivity to climate change.

2. From the view of oceanography, the [Barents and Kara Seas] BKS is close the the North Atlantic and it is one of the major pathways for the North Atlantic warm water into the Arctic Ocean.

3. From the view of atmospheric science/climate, similarly, it is easier for the atmospheric weather system like ARs, which develop and are active over the ocean, to come into the Arctic through the northwest coast of Europe.

There is no counterpart in the North Pacific since there is only a narrow channel, [the] Bering Strait. So, it is harder for the ocean currents to reach the Arctic through Bering Strait.

This quote comes from personal correspondence with Dr. Zhang.

Pengfei Zhang adds one more reason to study the Barents/Kara Sea region but it is not easy to understand. Essentially this region is, quote: “close to the climatological ridge of large scale circulation”. Atmospheric rivers can create a state in phase with existing climate. That harmony can: “influence the atmospheric circulation – even the stratospheric circulation.” He cites one of his previous papers published in Science Advances in 2018 titled: “A stratospheric pathway linking a colder Siberia to Barents-Kara Sea sea ice loss.


A steady stream of measurements from satellites over the past 40 years demonstrates the number of Atmospheric Rivers is increasing as the world warms. It is not new for them to reach the Poles, but the increase is new, and has newly discovered impacts on the ice world, known technically as “the cryosphere”.

The paper by Zhang et al points to three main changes. When the AR’s reach Antarctica they lead to more snow accumulation in East Antarctica. But, “intense moisture and heat that are rapidly transported by ARs can exert a strong melting effect on the cryosphere, exemplified by

ice sheet melt in Greenland and West Antarctica,

polynyas in the Weddell Sea and

the 2016–2017 record low Arctic winter sea-ice growth. “

According to Wikipedia:

“A polynya is an area of open water surrounded by sea ice. It is now used as a geographical term for an area of unfrozen seawater within otherwise contiguous pack ice or fast ice.” The Weddell Sea is a very large part of the Southern Ocean, off the coast of Antarctica in the direction of South America. It is claimed by Argentina, Chile, and Britain. The Weddell Sea has large ice shelves at it’s fringes, but some of them have disappeared by 2010.

Ice sheet melt in Greenland and West Antarctica is quite important to sea level rise, and tempers the speed of glaciers moving toward the sea. But this paper puts the focus on Arctic winter sea ice.


How do atmospheric rivers lead to weaker sea ice, and more warming? Several key drivers appear. The first is “enhanced downward long-wave radiation”. These are the long waves traveling all the way from the Sun, arriving at the surface, whether land or sea. Longwave radiation is difficult and expensive to measure, so weather stations leave them out. But that is what warms the world.


According to the new paper:

The physical processes relevant to AR-induced ice melt or impeded ice growth include:

(1) enhanced downward long-wave radiation (DLW) due to the greenhouse effect of water vapour, the cloud radiative effect (CRE) and condensational heating release,

(2) reduction or even sign change in turbulent heat fluxes from the ice surface,

(3) the insulating capacity of snow and

(4) melt energy carried by rainfall

Or course we expect rain will help melt ice in the Arctic. Zhang says this heat from rainfall is a “weak force” and we still do not know enough about it.


Here is another surprise. Scientists expected lower summer sea ice would lead to faster ice formation in the winter, even during warming. But that expectation has been overwhelmed by the episodic storms of atmospheric rivers. They find: “frequent ARs can prevent the sea ice from growing to the extent allowed by the freezing temperature.”

Perhaps because most Atmospheric Rivers are accompanied by strong storms, these scientists predict the Arctic will become more stormy, as we heat the world. Storms break up sea ice faster. Stormy weather could also affect the dreams of international shippers wanting to use the Arctic as a shortcut between Asia and Europe. If the Arctic Ocean stays open longer, China saves 2700 nautical miles shipping products to Europe – through the Arctic instead of the Suez Canal.

The obvious impact of winter sea ice weakened by repeated Atmospheric Rivers is simple. The frigid dark winter at the Poles is the time when sea ice solidifies. Arctic ice used to cover pretty well the whole Arctic sea with ice piles of thick ice, some of it years old.  A portion of that gradually melted away each summer.

But now in the age of fossil fuels, that regime is breaking down. If the winter sea ice is thinner and more fragile, there is less resistance to the Spring sun and increasing heat. Summer sea ice also suffers. That slashes reflection of solar rays back to space, a former cooling mechanism. Instead it allows the sun to heat more ocean surface, where heat is stored and eventually circulates around the world. Increasing Atmospheric Rivers in the Arctic are partly caused by global warming, and lead to still more warming.


In this story of rivers of air arriving from the Tropics, there are other impacts, but they are hard to describe. Changes in the winter Arctic can drive big weather changes much further south, like in Europe, the USA, or China.

Twice in recent years we had pro meteorologist and climate scientist Judah Cohen on Radio Ecoshock, to explain those connections. Although the process of cause and effect, is still under study, Cohen says we know enough to use the state of snow cover, over Siberia and the Arctic Sea, to predict large-scale weather patterns over the following year.

Other scientists, like Jennifer Francis of Rutgers, have also long said the state of Arctic Sea Ice can negatively affect weather further south, including the U.S. Not all scientists agree. UK scientists James Screen and Russell Blackport published three papers saying the impact of Arctic sea ice on climate further south was not significant. But more and more science shows there is a link between the state of Arctic ice and weather further south. Our new paper by Zhang and colleagues is further confirmation.

According to an article on “Weather Whiplash” published by NASA: “In a study published in Science in 2021, Cohen and colleagues linked declines in Arctic sea ice in the Barents and Kara Sea and increases in snowfall in Siberia – both of which are linked to climate change – with an increase in polar vortex disruptions and cold spells in the midlatitudes.” Cohen added: “The stretching of the polar vortex we saw in December 2022 definitely fits that pattern.”

In a 2020 paper, Pengfei Zhang led a paper investigating “North American cold events following sudden stratospheric warming in the presence of low Barents-Kara Sea sea ice”.


Let’s take the case of China. We have fresh research from Chinese scientists published in April 2022. The title is: “Possible Lagged Impact of the Arctic Sea Ice in Barents-Kara Seas on June Precipitation in Eastern China.” This is surely teleconnection. The matching pattern stretches not just over a massive continent, from the Norwegian north coast to China, but over time as well, arriving months to half a year later!

The authors, led by Dr. Huidi Yang, say: “…it is revealed that the state of sea ice concentration in Barents/Kara Seas from November to December is closely related to regional precipitation in June, which is most evident across the Yangtze/Huai Rivers Valley and South China.

The two states, one in the Arctic, the other in Eastern China, seem to move in concert. How is that possible? We do not yet know for sure. The authors offer suggestions. For example, they say:

… the sea ice concentration usually has a long memory, which exerts a long-lasting and lagged impact, although the sea ice anomaly amplitude gradually weakens from early winter to early summer.

Then it gets hairy and technical. Apparently “an increase in Barents–Kara sea ice usually corresponds to a stronger stratospheric polar vortex in midwinter”. This changes atmospheric wave action. But when the winds surrounding the Arctic recover and tighten up, that triggers a response in summer weather systems over parts of China the following June.  That is my untrained understanding of it.


Finally we return the dark threat of “episodic” climate change as shown in the new paper by Zhang et al.  Most past science, and public perception, measured and predicted global warming as a gradual slope. The precept is: Nature moves regularly and slowly. For example, they said the world is warming at about .1 degree C per decade. Charts show a gradual incline.

But others scientists, including Tim Lenton and Stephen Schneider question this linear view. What if warming, and all it’s life-changing impacts, does not ramp up in an orderly fashion, but jumps up from time to time and never goes back? Could we encounter a sudden warming within a year or two, or a surprising sea level rise washing into ports and agricultural deltas?

Previously, scientists considered this unlikely because of the massive buffering capacity of the ocean. But now the seas are hotter too. Their ability to keep absorbing our carbon dioxide pollution at the same rate is called into question by a large variety of factors, even including the response of plankton.


For years, models predicted sea level rise as a ramp up, on a knowable curve. But the science of past climates shows otherwise. Here is one example, you heard on Radio Ecoshock. Dr. Pankaj Khanna of Rice University, Texas told us about a series of coral plateaus off the coast in the Gulf of Mexico.

Expect A Sudden Sea Level Event

It works like this: coral animals depend on co-habitation with tiny plants that require a careful balance of nutrients, coming from the depths, and light from above. Too far in either direction up or down and the coral fails. They build their reefs at the sweet-spot depth, and can adjust to gradual changes in sea level, over long periods of time.

But if see levels go up precipitously, a steep step up rather than a ramp, then the partners of the coral polyps lose the light. We could say the coral “drowns”. The reef dies out and construction stops. That leaves a dead reef plateau. Finally new coral arrives and begins at the best depth and light conditions – until another rapid sea level rise. There are several of these plateaus in the Gulf of Mexico. They testify to several events of abrupt sea level rise.

This new 2023 study led by Zhang finds winter sea ice decline in the Arctic due to episodic extreme weather events, namely Atmospheric Rivers. It is more proof that natural systems do not operate within the limits of our convenience, or imagination. Climate disruption may indeed be “non-linear”.


In a brand new paper, Professors Tim Lenton, John Schellnhuber, Johann Rokstrom and colleagues again explore the possibility that known feed-back processes could collide. The result could be a jump in warming, a change in “normal” weather, or sudden impacts to destabilize the world. I will talk with Dr. Lenton about this in next week’s program.

The “episodic” view of climate change is gaining more voices and proof in facts. It should send tingles down your spine. All those dreams of a gradual ramp toward Net Zero are dangerous. They insist the future will be like the past, just pushed a bit every year. Nature itself promises no such convenient time to adapt.

Larger and unexpected impacts are possible. We may have already stimulated abrupt climate change. Or are we just approaching that doom? Either way, one way or another, humans need to stop bringing fossil fuels out of the ground. We need emergency action, because climate change is not our friend. Again we learn with new science, time is short to avoid climate disaster on a global scale. Expect the unexpected.




The Global Reach of Atmospheric Rivers: From the Arctic to Antarctica to the Equator and In-Between

SEE ALSO: From Columbia Climate School “More Frequent Atmospheric Rivers Are Hindering the Recovery of Arctic Sea Ice”.

More Frequent Atmospheric Rivers Are Hindering the Recovery of Arctic Sea Ice



Santa Monica California issues it’s first blizzard warning ever. Freaky waves of extreme heat and cold flow across North America. Australia just issued fresh heatwave warnings, hit with the “worst heat in four years”. But you don’t hear about the eight major heatwaves sweeping across the south of South America. Coupled with two years of extreme drought, major food exporters like Argentina and Brazil have less for a global market already stressed by war. Argentina hit 100% inflation and could go bankrupt again. Even at night, in Buenos Aires was too hot to sleep. But is it global warming? Yes and no.

Listen to or download this 28 minute interview with Dr. Paola Arias in CD Quality or Lo-Fi


Food prices are higher again. Only a few places grow most of world’s agricultural exports. One is Ukraine. You know the trouble there. We find another in the great plains of South America, including the famous “Pampas”. Wheat and soy crops in Argentina have been cut in half, and they are major exporters. This is another year of drought in a region known for increasing rains. The eight consecutive heat waves have been brutal. Obviously global warming has struck again. Or has it?

On February 16, 2023, the New York Times wrote about your new study with this headline: “Scientists Wondered if Warming Caused Argentina’s Drought. The Answer: No.” The New York Times said “No”. But what do the scientists say?

We are joined by Dr. Paola Arias Gomez, a climate scientist and professor at the Environmental School of the University of Antioquia. She is the lead author in the new study: “Vulnerability and high temperatures exacerbate impacts of ongoing drought in Central South America”. Arias Gomez was the first Colombian woman to be selected as an author for the Intergovernmental Panel on Climate Change, working on the latest Sixth Assessment Report. She has led or co-authored over 100 peer-reviewed science papers.

Dr. Paola Arias-Gomez, Columbia



Vulnerability and high temperatures exacerbate impacts of ongoing drought in Central South America

An earlier report on the record December 2022 heat waves in Southeastern South America by World Weather Attribution found warming made that heat 60 times more likely to happen.

Climate change made record breaking early season heat in Argentina and Paraguay about 60 times more likely


A 2021 study led by Arianna Varuolo-Clarke found summer rainfall in Southeastern South America has increased by 27% in the period 1902 to 2019. Some crops more than doubled because of dependable rain. The models predict it will get wetter still with more global warming. Why did that long trend of increasing rainfall break into a three year drought?

I planned to spend a few minutes looking into the factors for rainfall in this region. After a few hours, I barely scratched the surface. This is one of the most complex intersections of large-scale climate factors I have ever encountered. Let’s talk about a couple of them, including the unexpected – like the Ozone hole over Antarctica. How does that affect farming in Argentina, Brazil and Uruguay? One study suggested ozone depletion may be a larger factor in regional weather than global warming, at least since 1960.

In 2017 I interviewed Norwegian scientist Douglas Sheil. He and two Russian scientists offered a novel view of how great forests can make their own rain. Here is a link to an earlier (2009) paper co-authored by Douglas Sheil: “How forests attract rain: an examination of a new hypothesis” which talks about the biotic pump. In our interview Paola agrees about forest rain-making, and say deforestation is also a factor in recent drought in Southeast South America.

At the Climate Crossroads


The same study led by Arianna Varuolo-Clarke found “Gross Discrepancies” between predictions by even the latest, biggest climate models, and what actually happens with rainfall there. This huge region of South America is affected by so many factors, including the well-known El Nino/La Nina cycle (ENSO) – that even the best climate models cannot yet capture it. And yet the world has come to depend on it’s agricultural exports.


The National Meteorological Service of Argentina reported this Southern Hemisphere summer was the hottest November to January since 1961. The heat got worse this February, breaking records in 27 cities. The capital Buenos Aires was cooking, even at night. The extreme heat, Arias-Gomez tells us, is probably due to global warming but not the drought.

This drought really matters. Argentine exports of food and animal food have plummeted, just as the country hit 100% inflation and looming bankruptcy. People all over the world buy South American meat and soy products, including animal feed. These are hard times for Argentine farmers and the country. But so far, the best scientific estimate is that global warming is not the primary cause of this drought. It might have happened anyway as part of natural variability. There are long cycles of drought and rainfall in this region, as there are in the American West. From the UK, study co-author Otto Friedricke told the Times this attribution study shows: “not every bad thing that is happening now is happening because of climate change.


The show closes with quick reading from famous activist Greta Thunberg, reading from her work: “The Climate Book” from Penguin.  She tells us like it is.

We are out of time. I’m Alex Smith. Tune in again next week for Tim Lenton and the very serious and funny author Andrew Boyd.  He wants a “better catastrophe”.

Please support this independent science-based journalism if you can.  Thank you for listening, and caring about our world.