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Questions tagged [paleoclimatology]

Paleoclimatology concerns climate and climate variability before the onset of instrumented measurements.

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What were CO2 levels in Carboniferous?

What were CO2 levels in early and late Carboniferous, an what were mean levels? Who are the sources for these figures?
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Human activities in Prehistory, and Global Cooling

If we assume that nowadays the humans are responsible of the global warming by the emission of too much CO$_2$ in the atmosphere, why we should not assume that the Ice Ages occurred because the ...
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How Hot was the Oligocene?

When studying the paleoenvironment of the Oligocene epoch, a period in Earth's history spanning from 34 to 23 million years ago, I had a really hard time understanding what the climate was like in ...
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How many extreme shifts in climate has Earth gone through in its existence?

As the Earth formed, it went through cycles of essentially hotter and colder periods. Extremely volcanic times and ice ages, in feedback loops contributing to one another. CO2 swinging from high to ...
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How did $\text{CO}_2$ originate on Earth before there was life?

To start life there has to be $\text{CO}_2$. $\text{Solar energy} + 6 {CO}_2 + 6 H_2O \longrightarrow C_6H_{12}O_{6} \text{ (sugars)} + 6 O_2$ $C_6H_{12}O_{6} + O_2 \longrightarrow H_2O + {CO}_2 + \...
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Why the $\delta \, ^{18}\text{O}$ in foraminifera shells decrease with temperature even if the oceanic $\delta \, ^{18}\text{O}$ stay constant?

I understand why foram shells contain more $^{18}\text{O}$ when there are ice sheets present, since $^{16}\text{O}$ evaporates more readily and gets trapped in the ice, increasing the relative ...
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Does general relativity influence climate (vs Newtonian mechanics)

That may sounds like a silly question but here it is. One of the early great successes of general relativity was to explain the discrepancy between the prehilion advance of Mercury predicted by ...
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Would a volcanic winter trigger an oceanic “spring”?

There is large amounts of observations supporting the effects of volcanic eruptions on climate: A long term subtle warming effect due to $CO_2$ and a short term, but more intense cooling effect due ...
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For how long have the great karst springs of the Aachtal been active?

Aachtal, along with Lonetal, is a valley in the Swabian Jura, Germany, and the site of many famous archaeological sites of the upper Pleistocene. It also hosts a series of very large karst springs (...
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What caused the Carbon Dioxide Variations observed in the 800,000-year polar ice record?

I have seen several graphs showing the prehistoric temperatures and CO2 concentrations derived from ice-core data. My understanding is that CO2 and temperature correlate. I assume that Milankovich ...
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What was the density and composition of Earth's atmosphere during the Cretaceous warmest period?

There was time during the age of dinosaurs when the polar regions were ice free. The earth was obviously much warmer but a run-away greenhouse effect did not occur. This was most likely because the ...
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What makes a nuclear winter so extreme and destructive?

This may be a sort of, pertinent to the times, and disturbing question, inspired by the difficulties surrounding North Korea and the situation with it and nuclear weapons. I've heard of this idea of "...
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Is there a reconstruction of paleoclimate sea level air pressure?

In paleoclimateology graphs of both temperature and atmospheric composition versus time are common. Where can I find a reconstruction of sea surface pressure versus time? I have found one paper that ...
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What factors make Lake Turkana a great location for preserving fossils?

I am trying to figure out why Lake Turkana has yielded so many hominin fossils compared to other locations in the East African Rift Valley. One of the reasons is possibly the laying of sedimentary ...
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Did climate cool down when underground hydrocarbons stocks formed?

As far as I understand, the dominant theory of modern climate change says that recent warming is mainly caused by the massive burning of hydrocarbons that used to be stored in solid form mostly ...
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Was Judea as desertified 2000 years ago as it is now?

The ancient fortress of Masada is currently so dry and forbidding that is hard to imagine anyone living there. Was the climate in the surrounding area more wet 2000 years ago, or was it as much a ...
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Any historical examples of destructive climate warming?

Summation: Local cooling climate changes, since the last ice age seem relatively common and all seem to cause significant harm to human population. But I can't find instances of the reverse, warming ...
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How Warm Was the Paleocene?

It's been said that 55 million years ago, a massive carbon surge raised global temperatures by five to eight degrees (or, in a more preferable translation, nine to 14.4 degrees Fahrenheit). This ...
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volcanic effects on the climate during Pangaea

Which influence does the constellation of the continents have on the global climate? Was the biosphere more susceptible to climatic effects a volcanic eruption may cause during the Permian than it is ...
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How were the sea levels around western Europe during the Medieval Warm Period?

The Medieval Warm Period (MWP) or Medieval Climatic Anomaly was a time from about 950 to 1250 when climate was warmer than in the timespans immediately before and after. My question is if this ...
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How long does earth take to recover from mass extinctions? What is “normal”?

Wikipedia states the following about the P-Tr extinction event: "Because so much biodiversity was lost, the recovery of life on Earth took significantly longer than after any other extinction event,[5]...
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What caused the earth's climate to stabilise ~10 thousand years ago?

We can see that the last glacial period ended 12-10K years ago. Interestingly enough, this also appears to coincide with the rise of large human civilisations. My question is: What caused the earth'...
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What does the precessional parameter measure?

I am wondering what is measured in the plots of change of precession, e.g. when describing Milankovitch Cycles. The values typically vary between .06 and −.06. I am also wondering about what the ...
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Is this scientific explanation of The Bible flood accurate?

I googled "the flood and freshwater fish" and came up with this question Christianity StackExchange: How did Noah preserve fresh water fish?. The writer makes a lot of claims like how the salinity of ...
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What's a frost-gley?

I've noticed this term in a book about Pleistocene East Europe. It's apparently a soil which was formed during the interstadials, but that's all my book says, and I can't find much more on the ...
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Did the surfaces of the oceans freeze over entirely during the snowball Earth periods?

According to the snowball Earth theory, all of Earth froze over at least once (possibly twice) in the far past. However, Wikipedia says that there are opponents of the theory who state that tropical ...
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Confirmation of historical El Niño events

As this year's boreal summer monsoon draws to a close interest automatically centers around forecasts for next summer's monsoon and the likelihood of possibly another El Niño event. This brings about ...
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Why is the ocean paleotemperature trend downwards?

In The Encyclopedia of Paleoclimatology and Ancient Environments by Vivien Gornitz (2008, Springer) it is found that 50 My ago the sea temperature was about 13ºC above the present value. . AFAIK the ...
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Did the Neolithic Revolution have an effect on the earth's climate?

I imagine that human agriculture had a major effect on the composition of flora across the planet's surface. Did the transition from gathering to growing have a measurable effect on climate? If so, ...
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Sources of $\ce{CO_2}$ during Carboniferous period

It is believed that during the Carboniferous period, fungi and bacteria lacked the biochemical means to decompose lignin and release $\ce{CO_2}$ back to the atmosphere. So dying trees carbon became ...
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How has and how does the lithosphere affect climate change?

The climatic system can be divided into five main components: the atmosphere, the hydrosphere, the lithosphere, the cryosphere and the biosphere. All these physical systems operate at different time ...
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How do we use oxygen isotopes as temperature proxy?

As far as I know scientists use oxygen isotope 16 to 18 ratio in air trapped in glaciers (or in old foraminiftera shells) as proxy for temperature in the past. I know that $\ce{^18O}$ is heavier, and ...
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Why deep ocean didn't freeze during snowball Earth?

I know that at least twice in its history Earth was totally frozen. I also know that the last time it happened there were already life on Earth, and it survived. In deep water, under the ice, which ...
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What does geochemical data tell us about Earth's earliest palaeoclimatic conditions?

Given that the age of the oldest zircon samples are about 4.4 billion years old, and meteorites and other extraterrestrial samples can also give us some indication about the Earth's composition into ...
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Is there conclusive evidence to refute an earlier oxygenation of the Earth's atmosphere?

The Great Oxygenation Event (sometimes called the Great Oxidation Event (GOE), as in the journal Nature) occurred around 2.2 to 2.45 billion years ago (Frei et al. 2009). However, in the article A ...
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Current consensus on the Messinian Salinity Crisis

In 1973, Hsü et al. explained the findings of a large evaporite deposit during the Messinian (Latest Miocene stage, ca. 6Ma) in the Mediterranean by a basin-wide desiccation event. It has been ...
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What, if any, paleoclimate data can be derived from igneous rocks?

Paleoclimate data often derives from sedimentary rocks. Metamorphic rocks can also contribute to paleoclimate information in a wide variety of ways. What about igneous rocks? I guess that this can ...
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How global was the Bonarelli Oceanic Anoxic Event?

The Bonarelli Event (a.k.a. OAE2) is a well-studied episode of "worldwide" oceanic anoxic event at the Cenomanian-Turonian boundary (ca. 94 Ma). It is characterized by the presence of organic-rich ...
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Did a gamma ray burst contribute to the Ordovician mass extinction?

According to the University of California Museum of Palaontology webpage The Ordovician Period, the late Ordovician period witnessed when Gondwana finally settled on the South Pole during the Upper ...
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Hypotheses about Silurian carbon isotope excursions?

The Silurian Period is now known to have undergone several significant positive $\delta^{13}C_{carb}$ excursions, namely the early Aeronian, Late Aeronian, Valgu, Ireviken, Mulde, Lau & Klonk ...
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Release mechanism for methane clathrate at the PETM

The Paleocene-Eocene Thermal Maximum (PETM) is a well-studied warming event near the Paleocene-Eocene boundary. It is characterized by its extreme warming rate: from onset to recovery the event lasted ...
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What was the Amazon like during Green Sahara?

It is said that the Amazon rainforest receives up to half of its nutrients via mineral dust from the Sahara desert. But a few thousand years ago, the Sahara desert was much more fertile, having a ...
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Historical atmospheric partial pressure & Henry's law constant

The explanation given for the fact that temperature has historically led CO₂ levels is Henry's law. Figure 1: Vostok ice core records for carbon dioxide concentration (Petit 2000) and temperature ...
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Does the time-lagged correlation between $\ce{CO2}$ and ocean temperature have a shorter timelag than the one between $\ce{CO2}$ and air temperature?

I'm talking about evidence from both proxy records in the last 50,000 years (if possible) and the recent past (if also possible)
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How was the Marinoan Glaciation triggered?

The Marinoan Glaciation (a.k.a. Elatina Glaciation) was a glaciation that is thought to have occurred towards the end of the aptly-named Cryogenian period at ca. 650Ma. It is particularly known as one ...
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Why are some theories as to the cause of glacation less popular among the scientific community?

There are a few theories as to the causes of glaciation. There's the Milankovitch Theory, which says that there are cyclical changes in Earth's orbit and in the tilt of Earth's axis that occur over ...
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How accurate are climate proxies in giving us a clear picture of global average temperatures throughout Earth history?

Since reliable modern records of climate only began in the 1880s, proxies provide a means for scientists to determine climatic patterns before record-keeping began, though it appears that the the ...
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Is this graph showing the average temperature on Earth going back millions of years accurate?

Looking for a historic record of the average temperature on Earth going back millions of years, and this 2002 graphic the from the PALEOMAP Project is currently the best I am able to find. Is it ...
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What caused the Younger Dryas cold event?

During the termination of the latest ice age the warming climate leading from glacial to interglacial conditions was abruptly reverted by a distinct but short (about 1300 years in duration) cold event,...
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Did the impact event that caused the Chicxulub-Crater definitively and single-handedly cause the Cretaceous-Paleogene extinction?

Opinions abound on the web. What is the state of the current science regarding this theory and what is the best evidence? Is the theory gaining or losing traction? If it's losing what's the best of ...