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Antarctic--Longer-Term Reconstructions

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Linking an ancient CO2 drop to the Antarctic Ice Sheet using algae as a proxy. From Purdue University , another “just in time for Durban” press release. When you see phrases like “the mother of all tipping points” and you know this is overhyped control knob science. Drop in carbon dioxide levels led to polar ice sheet, study finds WEST LAFAYETTE, Ind. – A drop in carbon dioxide appears to be the driving force that led to the Antarctic ice sheet’s formation, according to a recent study led by scientists at Yale and Purdue universities of molecules from ancient algae found in deep-sea core samples. The key role of the greenhouse gas in one of the biggest climate events in Earth’s history supports carbon dioxide’s importance in past climate change and implicates it as a significant force in present and future climate. The team pinpointed a threshold for low levels of carbon dioxide below which an ice sheet forms in the South Pole, but how much the greenhouse gas must increase before the ice sheet melts – which is the relevant question for the future – remains a mystery.

New Science: Arctic AND Antarctic Sea Ice More Extensive Today Than Nearly All Of The Last 10,000 Years. By Kenneth Richard on 18. October 2018 It is often claimed that modern day sea ice changes are “unprecedented”, alarming, and well outside the range of natural variability. Yet scientists are increasingly finding that biomarker proxies used to reconstruct both Arctic and Antarctic sea ice conditions since the Early Holocene reveal that today’s sea ice changes are not only not unusual, there is more extensive Arctic and Antarctic sea ice during recent decades than there has been for nearly all of the last 10,000 years. Antarctic Sea Ice Extent In the Southern Ocean surrounding Antarctica, the sea surface temperatures have been cooling since 1979.

Image Source: Jones et al., 2016 Image Source: Fan et al., 2014 Image Source: Purich et al., 2018 The decline in Southern Ocean temperatures has coincided with an increase in Antarctic sea extent since 1979. Image Source: Comiso et al., 2017 Antarctica warming rapidly, 1950s-1980s Declining Antarctic sea ice concentrations, 1950s-1980s. Finding: Antarctica’s Ross Ice Shelf has collapsed before.

The front of the Ross Ice Shelf floats in the Ross Sea, as seen from the cockpit of an LC130 aircraft flown by the New York Air National Guard. Photo by Matt Siegfried Retracing Antarctica’s Glacial Past LSU geologist uncovers new data to inform future sea level rise BATON ROUGE – More than 26,000 years ago, sea level was much lower than it is today partly because the ice sheets that jut out from the continent of Antarctica were enormous and covered by grounded ice — ice that was fully attached to the seafloor.

The ice sheets were as large as they could get and at the time, sea level was much lower because a lot of ice was sequestered on the continent. Bart and his students conducted one of the largest geological surveys of the Antarctic continental shelf to-date. The ice shelf is a critical part of the climate system, because it slows down the breaking up and melting of grounded ice, which results in sea level rise. Like this: Like Loading... February 19, 2016 In "Antarctic" June 13, 2013. More settled science: The West Antarctic Ice Sheet is 20 million years older than thought.

Antarctic Temperature Data Contradict Global Warming…”Much Warmer” 105 Years Ago! Growing sea ice Despite all the alarmist claims of an Antarctic meltdown, it is well known that the trend for sea ice extent at the South Pole has been one of growing ice rather than shrinking ice over the past 4 decades. Naturally many factors influence polar sea ice extent, such as weather patterns, winds, ocean currents and sea surface temperature cycles. One factor of course is also surface air temperature, which according to global warming theorists is rising globally. Cooling at Showa station Yet data show the warmer surface temperatures are refusing to happen in Antarctica!

As you will read below, it was far warmer 100 years ago. Showa Antarctic station has seen slight cooling over the 30 years. No trend at Davis Antarctic station In reply to Kirye, AndyOz tweeted that there also has been no warming at Australia’s Davis station over the past 50 years: Chart: Bureau of Meteorology, Commonwealth of Australia. South Pole contradicting global warming Antarctica was much warmer 100 years ago.

During last warming period, Antarctica heated up 2 to 3 times more than planet average | Scienmag: Latest Science and Health News. Following Earth's last ice age, which peaked 20,000 years ago, the Antarctic warmed between two and three times the average temperature increase worldwide, according to a new study by a team of American geophysicists. The disparity – Antarctica warmed about 11 degrees Celsius, nearly 20 degrees Fahrenheit, between about 20,000 and 10,000 years ago, while the average temperature worldwide rose only about 4 degrees Celsius, or 7 degrees Fahrenheit — highlights the fact that the poles, both the Arctic in the north and the Antarctic in the south, amplify the effects of a changing climate, whether it gets warmer or cooler.

The calculations are in line with estimates from most climate models, proving that these models do a good job of estimating past climatic conditions and, very likely, future conditions in an era of climate change and global warming. Cuffey and his colleagues, including Gary Clow of the U.S. Deglaciation in Antarctica Co-authors with Cuffey and Clow are Eric Steig, T.J. Glaciers In Antarctica Advanced During Little Ice Age | NOT A LOT OF PEOPLE KNOW THAT.

By Paul Homewood As we all know, Antarctica is melting, we’re all going to drown and its all your fault. Well maybe not. There is a growing body of evidence that the Little Ice Age affected the Antarctic just as much as the rest of the world, and as a result glaciers there expanded. It therefore follows that the retreat of the ice is simply a natural rebound from this. 1) The Little Ice Age on James Ross Island This study by Carrivick et al has analysed six glaciers on the island and found all six of the glaciers investigated have undergone significant decreases in glacier extent and elevation since their maximum (when they deposited these moraines). There are no absolute dates available for the age of these moraines. Not only does this offer more evidence that the LIA was worldwide, but that the period before the neoglacial advance, i.e. the MWP was warmer. Bertler et al found: Li et al, 2009: Orsi et al:

Antarctic Refrigerator Effect and Climate Sensitivity. Antarctic Refrigeration Effect, Climate Sensitivity, and Deformation Professionelle For the past 55 million years the global surface temperature has declined by more than 10°C from a “hot house” condition into an “ice house” with increasing temperature variability as depicted in Figure 1 (Mya = millions of years ago). During the Cretaceous and Early Cenozoic, glaciers and ice caps were absent from both Antarctica and Greenland.

Antarctica was covered in para-tropical vegetation and Greenland was home to crocodiles. More importantly for millions of years the oceans had been storing enormous amounts of heat. In contrast to near freezing temperatures today, Antarctic bottom waters averaged about 11°C, suggesting Antarctic coastal temperatures never dropped below 11°C even during the long polar nights.

Amazingly the equator to pole surface temperature difference averaged just 10°C compared to the 30°C gradient measured today. The Case Against a CO2 Climate “Control Knob. Antarctica cooling since Roman Times, climate models wrong (again) A new study suggests temperatures across Antarctica have been falling for the last 1,600 years. This natural climate change would have been a threat to baby penguins, forcing them to walk much further across sea-ice for food. (Looks like it was even worse for polar bears ). The cooling trend would have threatened inland lakes, shortened summer breeding periods, affected seal behaviour, extended glaciers over important habitats, and destroyed rare tundra. Any recent weak “man-made” warming trend would have slightly reversed this destructive slide — restoring the continent back to levels last seen in 1400AD. These trends are not what the Climate Models predicted for Antarctica. The Daily Caller: However, Stenni admits the “absence of significant continent-scale warming of Antarctica over the last 100 years is in clear contrast with the significant industrial-era warming trends that are evident in reconstructions for all other continents (except Africa) and the tropical oceans.” h/t GWPF.

New Antarctic Temperature Reconstruction. Stenni et al (2017), Antarctic climate variability on regional and continental scales over the last 2000 years, was published pdf this week by Climate of the Past. It includes (multiple variations) of a new Antarctic temperature reconstruction, in which 112 d18O and dD isotope series are combined into regional and continental reconstructions. Its abstract warns that “projected warming of the Antarctic continent during the 21st century may soon see significant and unusual warming develop across other parts of the Antarctic continent [besides the peninsula]”, but no Steigian red spots of supposedly unprecedented warming.

Long-time CA readers will be aware of my long-standing interest in Antarctic ice core proxies, in particular, the highly resolved Law Dome d18O series. One of my first appearances in Climategate emails was a request for Law Dome data to Tas van Ommen in Australia, who immediately notified Phil Jones in Sauron’s Tower of this disturbance in the equilibrium of Middleearth. The Antarctic Peninsula: No Longer the Canary in the Coal Mine - Antarctic Peninsula Cooled Nearly 1°C During 1999–2014.

Paper Reviewed Oliva, M., Navarro, F, Hrbácek, F., Hernández, A., Nývlt, D., Pereira, P., Ruiz-Fernández, J. and Trigo, R. 2017. Recent regional climate cooling on the Antarctic Peninsula and associated impacts on the cryosphere. Science of the Total Environment 580: 210-223. Climate alarmists generally contend that current temperatures are both unnatural and unprecedented, as a result of global warming caused by anthropogenic CO2 emissions; and they claim that this "unnaturalness" is most strongly expressed throughout the world's polar regions.

In this regard, they often point to warming on the Antarctic Peninsula (typically the Faraday/Vernadsky station) as the proverbial canary in the coal mine, where over the past several decades it has experienced warming rates that are among the highest reported anywhere on Earth. However, in recent years two studies have challenged this assessment.

Figure 1. References Carrasco, J.F. 2013. A “New” Theory About the Formation of the Antarctic Ice Sheet | Watts Up With That? Guest post by David Middleton One of the big mysteries in the scientific world is how the ice sheets of Antarctica formed so rapidly about 34 million years ago, at the boundary between the Eocene and Oligocene epochs.There are 2 competing theories:The first explanation is based on global climate change: Scientists have shown that atmospheric carbon dioxide levels declined steadily since the beginning of the Cenozoic Era, 66 million years ago. Once CO2 dropped below a critical threshold, cooler global temperatures allowed the ice sheets of Antarctica to form.The second theory focuses on dramatic changes in the patterns of ocean circulation.

The theory is that when the Drake Passage (which lies between the southern tip of South America and Antarctica) deepened dramatically about 35 million years ago, it triggered a complete reorganization in ocean circulation. Meet the new theorySame as the old theory The Earth’s climate rapidly cooled about 34 million years ago. Cenozoic atmospheric CO2.