Bolivian tropical Andean foothills
Ask any creationist who is up to date with the latest dogmas as handed down by creation cult leaders, and they'll assure you their magic creator created Earth just a few thousand years ago and fine-tuned it for the existence of life (especially their life, because it had them in mind all along).
The reality, however, is very different: not only is Earth very much older by several orders of magnitude, but it is a dynamic and changing world, not the fixed, unchangeable world that 'fine-tuning' implies. It resembles a system in chaos, where a small change in one part can cause profound and unpredictable changes in another part. This is especially true of the weather, but is no less true of ocean currents, tectonic activity and the composition of the atmosphere.
As though to illustrate this, although refuting creationism was probably far from the minds of the scientists - that is a mere incidental of scientific facts as usual - a team of scientists led by climatologists from Brown University, Providence, RI, USA have analyzed the record of climate change in the Andes over the past 16,000 years (i.e. from 6,000 years before Creationist dogma says the Universe was magicked into existence out of nothing) and shown that major changes were brought about ultimately by the level of atmospheric \(\small \ce{\(\small \ce{CO2}\)}\).
Do you have any data on climate changes in the Andes over the last 16,000 years? The Andes, a major mountain range in South America, has undergone significant climate changes over the last 16,000 years. These changes are recorded in various forms, including glacier movements, lake levels, and the composition of sediments and ice cores. Here’s an overview of key climate events in the Andes during this period:Their findings were published yesterday in Proceedings of the National Academy of Science (PNAS) and is explained by a Brown University press release:
- Last Glacial Maximum (~20,000 - 16,000 years ago)
- The Last Glacial Maximum (LGM) occurred around 20,000 years ago, when large ice sheets covered much of the Andes, particularly in the southern and central regions. The climate was much colder and drier than today, leading to expanded glaciers.
- Deglaciation and Early Holocene (16,000 - 10,000 years ago)
- After the LGM, the climate began to warm, leading to the retreat of glaciers across the Andes. This period is marked by a gradual transition from cold, dry conditions to warmer and wetter conditions, especially during the early Holocene (~11,700 years ago).
- During the early Holocene, there were significant shifts in precipitation patterns, with increased rainfall in some regions leading to the growth of high-altitude lakes and wetlands.
- Mid-Holocene Climatic Optimum (~8,000 - 5,000 years ago)
- The Mid-Holocene was a period of relatively stable and warm climate conditions. During this time, glaciers in the Andes were smaller, and many regions experienced higher temperatures and increased precipitation.
- In some areas, such as the Altiplano, lake levels were high due to increased precipitation. This period is often referred to as the "Holocene Climatic Optimum" because it was warmer than preceding periods.
- Late Holocene (Last 5,000 years)
- The Late Holocene has been characterized by a series of climatic fluctuations, including periods of warming and cooling. Notable events include the "Little Ice Age" (~1300-1850 AD), during which glaciers advanced in the Andes.
- There were also periods of increased aridity, such as the Medieval Climate Anomaly (~900-1300 AD), when some regions experienced drier conditions.
- Recent Climate Change (Last 150 years)
- In the last century and a half, the Andes have experienced rapid warming, leading to accelerated glacier retreat, reduced snow cover, and changes in hydrology. This warming is linked to global climate change and has significant implications for water resources and ecosystems in the region.
Key Indicators of Climate Change
- Glacial Evidence: Glacial moraines and ice cores provide crucial evidence of past glacial extents and climate conditions.
- Lake Sediments: Sediments from high-altitude lakes in the Andes contain records of past precipitation, temperature, and vegetation changes.
- Paleobotanical Data: Fossilized pollen and plant remains help reconstruct past climate and vegetation patterns.
Impact on Human Societies
- The climate changes in the Andes have also influenced human societies, particularly in terms of agriculture, water availability, and settlement patterns. For example, the development of complex agricultural systems in the high Andes is closely tied to periods of favorable climate conditions.
Current Research
- Ongoing research in the Andes includes studies on glacier dynamics, hydrology, and ecosystem responses to modern climate change. This research is crucial for understanding the future impacts of climate change on the region.
If you need more specific data or references on any of these periods, I can provide additional details or point you to relevant studies.
Briefly, what and when was the Antarctic Cold Reversal (ACR)?
The Antarctic Cold Reversal (ACR) was a significant climate event that occurred between approximately 14,500 and 12,800 years ago. During this period, temperatures in the Southern Hemisphere, particularly in Antarctica, temporarily cooled after a long period of warming following the Last Glacial Maximum.
Key Points:
- Timing: The ACR took place roughly from 14,500 to 12,800 years ago, overlapping with the onset of the Bølling-Allerød warming in the Northern Hemisphere but preceding the Younger Dryas, a cooling event in the Northern Hemisphere.
- Characteristics: The ACR is marked by a drop in temperatures in Antarctica by about 2-3°C. This cooling interrupted the general trend of post-glacial warming in the region.
- Significance: The ACR highlights the asynchronous climate changes between the Northern and Southern Hemispheres during the deglaciation period. While the Northern Hemisphere was experiencing warming, the Southern Hemisphere underwent a temporary cooling phase.
- Causes: The causes of the ACR are not fully understood, but it is believed to be related to changes in oceanic circulation, particularly the weakening of the Atlantic Meridional Overturning Circulation (AMOC), which affected heat distribution between the hemispheres.
The ACR is an important event for understanding global climate dynamics during the transition from the Last Glacial Maximum to the current interglacial period.
New study unveils 16,000 years of climate history in the tropical AndesSadly, the main body of the paper in PNAS is behind an expensive paywall, so only the abstract is available:
Brown University researchers highlight the roles of carbon dioxide and ocean currents as key drivers of temperature fluctuations in the tropical Andes over a 16,000-year period.
A new study that explores ancient temperatures and rainfall patterns in the tropical Andes of South America has revealed how 16,000 years of climate history in this part of the world was driven by carbon dioxide levels and ocean currents from global climate events.
Led by Brown University researchers, the study marks the first high-resolution temperature record covering the past 16,000 years in the tropical Andes and could help scientists predict and mitigate future climate impacts in tropical regions of the planet. The work is described in the Proceedings of the National Academy of Science.
Usually when we study climate change in the past, we emphasize the Northern Hemisphere or Southern Hemisphere because of the outsized role they play in affecting climates all over the globe. One of the biggest questions we are getting at is what are the driving factors behind temperature history in this part of the tropics, so that we can begin to potentially apply that data and knowledge to other tropical regions.
Our evidence here suggests that temperatures in this region of the world are more influenced by the Southern Hemisphere — so places like Antarctica.
Boyang Zhao, first author
Department of Earth, Environmental and Planetary Sciences
Brown University, Providence, RI, USA.
Along with future implications, the new study provides a unique look at the way distinct and distant parts of the world influence temperature and weather elsewhere, emphasizing how regional climates are connected to global climate changes.
The study focused on an analysis of sediment samples from Laguna Llaviucu, a lake located in Ecuador’s Cajas National Park. The measurements from the sediment samples showed that temperature variations in the tropical Andes closely aligned with climate events that saw the planet’s temperatures rise and fall during the past 16,000 years.
Overall, the evidence showed that the main driver in these temperature fluctuations was the concentration of \(\small \ce{CO2}\). Researchers saw evidence that the tropical Andean temperatures track with Antarctic temperatures, which are mainly controlled by carbon dioxide concentrations. The findings showed that about 17,000 to 14,000 years ago, tropical Andean temperatures rose when carbon dioxide increased and that the temperatures remained relatively stable about 12,000 years ago when carbon dioxide levels remained relatively stable.
Zhao said that the findings support previous research identifying carbon dioxide as a key driver of global temperature changes since the last Ice Age.
The study also highlighted the role of ocean currents that move warm water from the tropics to the North Atlantic. During a cooling period known as the Antarctic Cold Reversal 14,500 years ago, the northward current was strengthened, causing it to transport more heat northward and cool sea surface temperatures in the south. The researchers found that this cooling effect extended to the tropical Andes.
To reconstruct past climate conditions, the researchers analyzed lipid biomarkers and hydrogen isotopes collected in 2009 from Laguna Llaviucu by scientist Mark Bush from the Florida Institute of Technology. Lipid biomarkers are chemical compounds that provide clues about past temperatures and rainfall patterns. The high-resolution data, combined with accurate dating techniques, allowed the team to create a detailed timeline of climate changes over the past 16,000 years.
According to the researchers, this is the first time organic biomarkers have been used to put together a quantitative climate history for tropical South America. It is traditionally difficult to reconstruct temperatures from the tropics.
The study also points out a number of regional differences in temperature patterns, like how the tropical Andes and Southeast Asia cooled during certain historical periods while other regions like Africa did not. The research also shows how local factors may help to counteract the global effects of rising \(\small \ce{CO2}\) levels by looking at differences between past temperature models and what the sediment data show.
Mountain environments are some of the most sensitive regions on Earth to climate change. In fact, in the near future, high tropical mountains, such as the Andes, are predicted to experience a rate of warming second only to the Arctic, which is the fastest warming part of the planet.
Professor James Russell, senior author
Professor of Earth, environmental, and planetary sciences
Bron University, Providence, RI, USA.
The researchers from Brown plan to continue to explore past temperature patterns in this part of the world that historically lacks complete climate records.
Along with Zhao and Russell, authors from Brown also included undergraduate student Aaron Freeman. This work was supported by the U.S. National Science Foundation.
SignificanceA yawning chasm like this between what the dogma says and what the science shows, would cause anyone with a degree of humility that is missing in creationists, to conclude that there might be a flaw in their dogma. Not a creationist, however. So convinced are they of the inerrancy of their evidence-free beliefs that they insist it’s the scientific evidence which is wrong.
Tropical South America is a center of biodiversity and is under pressure from ongoing climate change. Understanding tropical South America’s climate history can provide valuable insight into the water cycle, ecosystems, and future climate change, yet past temperature changes are not well-known. We reconstructed temperature and rainfall since ~16,800 y ago in the tropical Andes Mountains. In addition to warming driven by rising atmospheric \(\small \ce{CO2}\) concentrations, we observe rapid temperature changes linked to changes in the deep ocean circulation. Given the projected slowing of the Atlantic Ocean circulation in the coming decades, our findings suggest that Amazonia’s ecosystems may be challenged by rapid temperature changes superposed on warming from sharply increasing atmospheric \(\small \ce{CO2}\).
Abstract
Global warming during the Last Glacial Termination was interrupted by millennial-scale cool intervals such as the Younger Dryas and the Antarctic Cold Reversal (ACR). Although these events are well characterized at high latitudes, their impacts at low latitudes are less well known. We present high-resolution temperature and hydroclimate records from the tropical Andes spanning the past ~16,800 y using organic geochemical proxies applied to a sediment core from Laguna Llaviucu, Ecuador. Our hydroclimate record aligns with records from the western Amazon and eastern and central Andes and indicates a dominant long-term influence of changing austral summer insolation on the intensity of the South American Summer Monsoon. Our temperature record indicates a ~4 °C warming during the glacial termination, stable temperatures in the early to mid-Holocene, and slight, gradual warming since ~6,000 y ago. Importantly, we observe a ~1.5 °C cold reversal coincident with the ACR. These data document a temperature change pattern during the deglaciation in the tropical Andes that resembles temperatures at high southern latitudes, which are thought to be controlled by radiative forcing from atmospheric greenhouse gases and changes in ocean heat transport by the Atlantic meridional overturning circulation.
The same people also purport to worship a god who told them that vanity is a mortal sin.
What Makes You So Special? From The Big Bang To You
How did you come to be here, now? This books takes you from the Big Bang to the evolution of modern humans and the history of human cultures, showing that science is an adventure of discovery and a source of limitless wonder, giving us richer and more rewarding appreciation of the phenomenal privilege of merely being alive and able to begin to understand it all.
Available in Hardcover, Paperback or ebook for Kindle
Ten Reasons To Lose Faith: And Why You Are Better Off Without It
This book explains why faith is a fallacy and serves no useful purpose other than providing an excuse for pretending to know things that are unknown. It also explains how losing faith liberates former sufferers from fear, delusion and the control of others, freeing them to see the world in a different light, to recognise the injustices that religions cause and to accept people for who they are, not which group they happened to be born in. A society based on atheist, Humanist principles would be a less divided, more inclusive, more peaceful society and one more appreciative of the one opportunity that life gives us to enjoy and wonder at the world we live in.
Available in Hardcover, Paperback or ebook for Kindle
No comments :
Post a Comment
Obscene, threatening or obnoxious messages, preaching, abuse and spam will be removed, as will anything by known Internet trolls and stalkers, by known sock-puppet accounts and anything not connected with the post,
A claim made without evidence can be dismissed without evidence. Remember: your opinion is not an established fact unless corroborated.