Marine life found in ancient Antarctica ice helps solve a carbon dioxide puzzle from the ice age
"These are the best arguments from the 3% of climate scientist 'skeptics.' Really. "Trump withdrew from the Paris climate deal a year ago. Here’s what has changed." Contrarian climate scientist Roy Spencer summed up the contrarian case for a fossil fuel and tobacco-funded think tank"
July 7, 2020 5.54am AEST
Authors Chris Turney Professor of Earth Science and Climate Change, Director of the Changing Earth Research Centre and the Chronos 14Carbon-Cycle Facility at UNSW, and Node Director of the ARC Centre of Excellence for Australian Biodiversity and Heritage, UNSW
Chris Fogwill Professor of Glaciology and Palaeoclimatology, Head of School Geography, Geology and the Environment and Director of the Institute for Sustainable Futures, Keele University
Disclosure statement Chris Turney receives funding from The Australian Research Council and is a scientific advisor to cleantech graphite company, CarbonScape ( https://www.carbonscape.com/ ).
Chris Fogwill receives funding from UK Research and Innovation and The Australian Research Council.
Partners UNSW and Keele University UNSW provides funding as a member of The Conversation AU. Keele University provides funding as a member of The Conversation UK.
Evidence of minute amounts of marine life in an ancient Antarctic ice sheet helps explain a longstanding puzzle of why rising carbon dioxide (CO2) levels stalled for hundreds of years as Earth warmed from the last ice age.
And surprisingly, this marine life once played a part regulating the climate. Hence, this finding has big implications for future climate change projections.
Walking into the past
Our research took us on a four-hour flight from Chile to the Weddell Sea, at the extreme southern end of the Atlantic Ocean, to land on an ice runway at a frigid latitude of 79° south.
Our Ilyshion aircraft landed on the Union Glacier (Antarctic Logistics and Expeditions). Chris Turney, Author provided
The Weddell Sea is frequently choked with sea ice and has been hazardous to ships since the earliest explorers ventured south.
We spent three weeks in the nearby Patriot Hills, drilling through ice to collect samples.
Normally when scientists collect ice samples, they drill a deep core vertically down through the annual layers of snow and ice. We did something quite different: we went horizontal by drilling a series of shorter cores across the icescape.
That’s because the Patriot Hills is a fiercely wild place strafed by Weddell Sea cyclones that dump large snowfalls, followed by strong frigid winds (called katabatic winds) pouring off the polar plateau.
&feature=emb_title Those katabatic winds blowing hard.
As the winds blow throughout the year, they remove the surface ice in a process called sublimation. Older, deeper ice is drawn up to the surface. This means walking across the blue ice towards Patriot Hills is effectively like travelling back through time.
A walk across the blue ice is a walk back in time. Matthew Harris, Keele University, Author provided
The exposed ice reveals what was happening during the transition from the last ice age around 20,000 years ago into our present warmer world, known as the Holocene .. https://www.britannica.com/science/Holocene-Epoch .
The Antarctic Cold Reversal
As Earth was warming, carbon dioxide levels in the atmosphere were rising rapidly from around 190 to 280 parts per million.
But the warming trend wasn’t all one way.
Starting around 14,600 years ago, there was a 2,000 year-long period of cooling in the Southern Hemisphere. This period is called the Antarctic Cold Reversal .. https://www.nature.com/articles/ngeo2580 , and is where CO2 levels stalled at around 240 parts per million.
Why that happened was the puzzle, but understanding it could be crucial for improving today’s climate change projections.
Finding life in the ice
Over three weeks we battled the winds and snow to make a detailed collection of ice samples spanning the end of the last ice age.
We collected sample of ice to study later in the lab. Chris Turney, Author provided
To our surprise, hidden in our ice samples were organic molecules – remnants of marine life thousands of years ago. They came from the cyclones off the Weddell Sea, which swept up organic molecules from the ocean surface and dumped them onshore to be preserved in the ice.
Antarctic ice, which forms from snowfall, usually only tells scientists about the climate. What’s exciting about finding evidence of life? in ancient Antarctic ice is that, for the first time, we can reconstruct what was happening offshore in the Southern Ocean at the same time, thousands of years ago.
We found an unusual period, displaying high concentrations and a diverse range of marine microplankton. This increased ocean productivity coincided with the Antarctic Cold Reversal.
Sea ice formed in winter melts in summer, and dumps nutrients into the ocean. Shutterstock
As the world lurched out of the last ice age, the summer warmth destroyed large amounts of sea ice that had formed through winter. When the sea ice melts, it releases valuable nutrients into the Southern Ocean, and fuelled the explosion in marine productivity we found in the ice on the continent.
This marine life caused more carbon dioxide to be drawn from the atmosphere as it photosynthesised, similar to the way plants use carbon dioxide. When the marine life die they sink to the floor, locking away the carbon. The amount of carbon dioxide absorbed in the ocean was sufficiently large to register around the world.
Marine life in the Southern Ocean still plays an important role in regulating the amount of atmospheric carbon dioxide.
But as the world warms with climate change, less sea ice will be formed in polar regions. This natural carbon sink of marine life will only weaken, increasing global temperatures further.
It’s a timely reminder that while the Antarctic may seem remote, it’s impact on our future climate is closer and more connected than we might think.
Sea ice is found in remote polar oceans. On average, sea ice covers about 25 million square kilometers (9,652,553 square miles) of the Earth, or about two-and-a-half times the area of Canada. Because most of us do not live in the polar regions, we may live for several decades and never see sea ice. Although it may not directly affect us, it is a critical component of our planet because it influences climate, wildlife, and people who live in the Arctic.
"All About Sea Ice" offers a glimpse of the characteristics and different forms of sea ice, why it is so important to our environment, and popular scientific methods for studying it. Sample images from data illustrate the type of information scientists seek to learn about sea ice. If you want a more in-depth, scientific discussion on the thermodynamics and physics of sea ice, visit the "Processes" section. Finally, we describe how sea ice affected explorers who struggled to reach the poles.
Post falsely claims Earth warmer than present for 83% of past 10,000 years
"These are the best arguments from the 3% of climate scientist 'skeptics.' Really. "Trump withdrew from the Paris climate deal a year ago. Here’s what has changed." P - Contrarian climate scientist Roy Spencer summed up the contrarian case for a fossil fuel and tobacco-funded think tank [...] The best case against climate concern is really bad All in all, Spencer managed to cram about 24 climate myths into a 13-point white paper. Most importantly, as Schmidt noted, the bulk of those myths served no purpose. P - Just consider Spencer’s very first argument. No scientist should ever claim that carbon pollution is benign because it’s only present in the atmosphere in trace amounts. For example, arsenic can be deadly if present in trace amounts in water; Spencer probably wouldn’t drink from a water source with 400 ppm .. https://www.theguardian.com/environment/2016/jun/16/antarctic-co2-hits-400ppm-for-first-time-in-4m-years .. of arsenic. This is an easily-refuted, scientifically-useless argument whose sole purpose seems to be fooling non-experts. It’s the climate version of the Chewbacca defense .. https://en.wikipedia.org/wiki/Chewbacca_defense .
"
Anuraag Baruah August 31, 2022
CLAIM
The Earth has been warmer than the modern era for 83 percent of the past 10,000 years.
FACT
The annual global temperature at the present is the warmest in the past 10,000 years.
WHAT THEY SAY
Climate deniers are claiming that the earth has been mostly warmer in the past 10,000 years than the present times and hence we have nothing to worry about as there is nothing called ‘global warming’ happening at the present. This claim has been often used to refute climate change. A Twitter post has recently gone viral with such a claim that we should actually ‘fear cold’ and not ‘warming’.
Here is the tweet:
Peter Clack @PeterDClack · Follow The Earth has been warmer than the modern era for 83 per cent of the past 10,000 years. On a longer scale, the interglacial period (known as the Holocene) is the ONLY time of global warming in 100,000 years. These are facts from climate studies by scientists. We should fear cold. 8:41 AM · Aug 26, 2022 3.5K Reply Copy link Tweet
WHAT WE FOUND
Scientists have recently concluded that the Earth at present is hotter than it’s been in at least 12,000 years based on the most recent annual global temperature data. According to a Rutgers-led study in the journal Nature .. https://www.nature.com/articles/s41586-020-03155-x , the annual global temperature at the present is the warmest in the past 10,000 years.
“Our reconstruction shows that the first half of the Holocene was colder than in industrial times due to the cooling effects of remnant ice sheets from the previous glacial period – contrary to previous reconstructions of global temperatures,” said lead author Samantha Bova .. https://eoas.rutgers.edu/important-climate-change-mystery-solved-by-scientists/ , a postdoctoral researcher associate in the lab of co-author Yair Rosenthal, a Distinguished Professor in the Department of Marine and Coastal Sciences and Department of Earth and Planetary Sciences at Rutgers University–New Brunswick. “The late Holocene warming was indeed caused by the increase in greenhouse gases, as predicted by climate models, and that eliminates any doubts about the key role of carbon dioxide in global warming.
Credit: Rutgers Institute of Earth, Ocean and Atmospheric Sciences
The study says, “that previous global reconstructions of temperature in the Holocene and the last interglacial period reflect the evolution of seasonal, rather than annual, temperatures and we develop a method of transforming them to mean annual temperatures…Furthermore, our reconstructions demonstrate that the modern global temperature has exceeded annual levels over the past 12,000 years…”
Holocene temperature conundrum
Holocene is an epoch encompassing the last 11,700 years of Earth’s history. The Holocene temperature conundrum is a debate about the changes in temperature during the Holocene. Earlier it was suggested by some researchers that the average temperature during the Holocene period peaked between 6,000 and 10,000 years ago and the planet cooled after this. Scientists have now found that global temperatures have actually risen over the past 12,000 years and factors like rising greenhouse gas emissions and climate change have contributed to it.
Present warming is ‘unprecedented’ in the last 24,000 years
Another study by a team of scientists from the University of Arizona concluded that global temperature reconstruction over the last 24,000 years shows that the present warming is ‘unprecedented’. For the study published in Nature .. https://www.nature.com/articles/s41586-021-03984-4 , the team created maps of global temperatures for each 200-year interval since the last ice age.
[No image for me] [img]Global average surface temperature since the last ice age 24,000 years ago. Time is stretched for the past 1000 years to visualize recent changes. Credit: Matthew Osman, Lead Author of the Study[/img]
The study says, “In contrast with previous proxy-based reconstructions, our results show that global mean temperature has slightly but steadily warmed, by ~0.5?°C, since the early Holocene (around 9 thousand years ago). When compared with recent temperature changes, our reanalysis indicates that both the rate and magnitude of modern warming are unusual relative to the changes of the past 24 thousand years.”
According to a 2020 study .. https://www.nature.com/articles/s41597-020-0530-7 , the warmest 200-year period of the Holocene before industrialization took place around 6500 years ago when global surface temperatures were about 0.7 degrees Celsius warmer than in the 19th century. However, later during the period from 2011 to 2019, temperatures averaged 1 degree Celsius higher than in the 19th century. This ultimately brings recent temperatures above that of the entire Holocene.
A 2022 technical note .. https://cp.copernicus.org/articles/18/911/2022/ .. by Prof Kaufman .. https://www2.nau.edu/~dsk5/ .. concludes, “human-caused global warming is now exceeding the warmest multi-century period of the Holocene and thereby the envelope of temperatures under which agriculturally based society has flourished”.
The IPCC Report
According to an assessment report .. https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM.pdf .. from the UN’s Intergovernmental Panel on Climate Change (IPCC), ‘Earth’s global surface temperature has increased by around 1.1 °C compared with the average from 1850–1900—a level that hasn’t been witnessed since before the last ice age, some 125,000 years ago.’
“Temperatures during the most recent decade (2011–2020) exceed those of the most recent multi-century warm period, around 6500 years ago [0.2°C to 1°C relative to 1850–1900]. Prior to that, the next most recent warm period was about 125,000 years ago, when the multi-century temperature [0.5°C to 1.5°C relative to 1850–1900] overlaps the observations of the most recent decade,” the IPCC report said.
Market Data 
Markets 
AI
