Questions tagged [paleoclimatology]

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

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How it's possible to measure temperature 2000 years ago with such precision?

I saw this graph about the global temperature, it goes back for 2000 years. How is it possible to measure temperature 2000 years back with such a precision of like ~0.1 C? The image from Reddit post I ...
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What is the status of the Raymo & Ruddiman idea that Tibet cooled the Earth?

What is the current status of the Raymo & Ruddiman hypothesis that the uplift of the Tibetan Plateau during the Cenozoic cooled the Earth, resulting the current ice age(*)? cf. Raymo, M.E. and W....
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What would it take to confirm or refute the Snowball Earth Hypothesis?

Since Harland's sedimentary work and Budyko's models in the 1960s, geologists have hypothesized that the Earth may once have been completely frozen. There are various lines of evidence for this event. ...
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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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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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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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How do we know that we are NOT in an "Ice Age?"

Historically, the earth has had five "Ice Ages" Each of them lasted millions, tens of millions, or hundreds of millions of years. The last ice age reportedly ended perhaps 10,000 years ago. That ...
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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 was the ocean circulation like during the time of Pangaea?

So Enderton and Marshall (2009) wrote an interesting paper on the ocean circulation of various aquaplanets covered with certain terrain: e.g. an aquaplanet with a small ridge of land that ranged from ...
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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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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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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 ...
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Is there any evidence for higher air pressures in the geological past?

I was curious about how the Earth's overall air pressure has varied over time, and tried to take a look around the internet. However, Google pops up a lot of sites with questionable science proposing ...
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What, if any, paleoclimate data can be derived from stromatolite fossils?

Stromatolite fossils have a layered structure vaguely reminiscent of tree rings, which are a well-known source for climate data. Although the formation process of stromatolite layers is less seasonal ...
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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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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 were we able to measure carbon dioxide levels in earlier climates?

It is said that carbon dioxide levels were much higher during the Cretaceous and Eocene periods: which proxies are used to determine paleo-pCO2?
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How did CO₂ originate on Earth before there was life?

To start life there has to be $\ce{CO2}$. $\ce{Solar energy + 6CO2 + 6H2O -> C6H12O6 (sugars) + 6O2}$ $C_6H_{12}O_{6} + O_2 \longrightarrow H_2O + {CO}_2 + \text{Energy}$ So to start this cycle, ...
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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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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 $\small\mathsf{CO_2}$ and a short term, but more intense ...
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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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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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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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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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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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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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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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Can we predict which annular modes existed during the time of Pangaea?

Some examples of annular modes include ENSO, NAM, and SAM. I think one of the major mysteries of them is how they formed to begin with. I'm just curious - do we have any idea of whether or not ...
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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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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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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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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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How has river to ocean flux changed over the last 500 million years?

Do we have any rough indices of how this flux has changed? I'm particularly interested in knowing whether the flux was higher or lower during the time of Pangaea, or during the time of the unusually ...
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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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478 views

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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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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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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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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Why is it that "With higher CO2, the dry gets drier and the wet gets wetter"?

The Phys.org article CO2 dip may have helped dinosaurs walk from South America to Greenland quotes Dennis Kent, "adjunct research scientist at Columbia University's Lamont-Doherty Earth ...
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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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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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Geological evidence about climate change: has there ever been a period with a rate of climate change as great as it is today?

Most statistics about climate change are based on climate data over the last 150 year (as long as records have been kept). This seems irrelevant in terms of the geological time scale of temperature ...
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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 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 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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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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Why did the carboniferous period have so much atmospheric oxygen?

Even if all the carbon dioxide (which makes up less than 1% of the atmosphere) in the air were sequestered by plants, would the atmosphere not remain about 21% oxygen? Why did the carboniferous period ...
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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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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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At least by theoretical biology - could there be, or should there have been, or was a "southern Taiga" on earth?

All data I have ever encountered about the Taiga "pole surrounding", vast, cold forests comprised mainly of Pinophyta trees, was about the ...