56 min. video, earth's past climates and the Milankovitch orbital cycles that drive earth's climate. - Page 2 - Politics Forum.org | PoFo

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#14978152
Researchers find bottom of Pacific getting colder, possibly due to Little Ice Age

Earth's climate cooled considerably across the transition from the Medieval Warm Period to the Little Ice Age about 700 years ago. Theoretically, owing to how the ocean circulates, this cooling should be recorded in Pacific deep-ocean temperatures, where water that was on the surface then is found today. Gebbie and Huybers used an ocean circulation model and observations from both the end of the 19th century and the end of the 20th century to detect and quantify this trend. The ongoing deep Pacific is cooling, which revises Earth's overall heat budget since 1750 downward by 35%.

The model showed that the Pacific Ocean cooled over the course of the 20th century at depths of 1.8 to 2.6 kilometers. The amount is still not precise, but the researchers suggest it is most likely between 0.02 and 0.08° C. That cooling, the researchers suggest, is likely due to the Little Ice Age, which ran from approximately 1300 until approximately 1870. Prior to that, there was a time known as the Medieval Warm Period, which had caused the deep waters of the Pacific to warm just prior to the cooling it is now experiencing.

Read more: https://phys.org/news/2019-01-bottom-pa ... y-due.html

Other sources:http://science.sciencemag.org/content/363/6422/70

https://www.mnn.com/earth-matters/clima ... -be-solved


^So what happens when warm surfaces finally reach the bottom?
Pacific Depths Likely to Keep Warming for Centuries Even if We Decarbonize Now, Study Shows

The slow-circulating deep Pacific is still cooling almost 200 years after the Little Ice Age ended, with worrying implications for the anthropogenic age

There is also no question that anthropogenic climate change is warming ocean surfaces and even the groundwater.

Because of how water circulates in the vast oceans, the oceanographers had suspected that temperature anomalies like the Little Ice Age might leave long-term traces in the overturning deep Pacific. The still-cooling water they have observed is just such a “memory,” they believe.

Their paper presents a model of the behavior of the “creeping waters,” not categorical facts. But they’re confident in it and if they’re right, one implication of their model is that even if we suddenly decarbonize and stop changing the climate, we could be contending with the depths of the Pacific Ocean continuing to warm at least for decades, possibly hundreds of years.

Read more: https://www.haaretz.com/science-and-hea ... -1.6809721


Melting ice sheets release tons of methane into the atmosphere

The Greenland Ice Sheet emits tons of methane according to a new study, showing that subglacial biological activity impacts the atmosphere far more than previously thought.

Read more: https://www.sciencedaily.com/releases/2 ... 110300.htm
#14979060
Earth’s magnetic field is acting up and geologists don’t know why

Erratic motion of north magnetic pole forces experts to update model that aids global navigation.

In the meantime, scientists are working to understand why the magnetic field is changing so dramatically. Geomagnetic pulses, like the one that happened in 2016, might be traced back to ‘hydromagnetic’ waves arising from deep in the core1. And the fast motion of the north magnetic pole could be linked to a high-speed jet of liquid iron beneath Canada2.

The jet seems to be smearing out and weakening the magnetic field beneath Canada, Phil Livermore, a geomagnetist at the University of Leeds, UK, said at the American Geophysical Union meeting. And that means that Canada is essentially losing a magnetic tug-of-war with Siberia.

“The location of the north magnetic pole appears to be governed by two large-scale patches of magnetic field, one beneath Canada and one beneath Siberia,” Livermore says. “The Siberian patch is winning the competition.”

Which means that the world’s geomagnetists will have a lot to keep them busy for the foreseeable future.

Read more: https://www.nature.com/articles/d41586-019-00007-1



No, We're Not All Doomed by Earth's Magnetic Field Flip

Fine. So what is a geomagnetic reversal?

If geologic history repeats itself, Earth’s magnetic poles should eventually swap places. This much is undeniable. Based on the magnetic fingerprints locked into ancient rocks, we know that over the last 20 million years, magnetic north and south have flipped roughly every 200,000 to 300,000 years (this rate has not been constant over the planet’s lifetime, though). The last of these major reversals occurred about 780,000 years ago, although the Poles do wander around in between these larger flips. (What’s more, climate change seems to be shifting Earth’s geographic poles.)

That means we’re a bit overdue for a total reversal, and some data do, in fact, suggest that a geomagnetic reversal is geologically imminent. But this does not mean a polar flip-flop is going to happen tomorrow, or even any time soon, and we’d put good money on North still being in the Arctic for a while—although neither we nor anyone else knows when the next total reversal will actually happen.

Read more: https://news.nationalgeographic.com/201 ... s-science/
#14987591
(Soundtrack)


As Insect Populations Decline, Scientists Are Trying to Understand Why

The real story behind reports of an “insect Armageddon” is more nuanced—but probably just as unsettling

Worldwide, a 2014 summary of global declines in biodiversity and abundance estimated a 45 percent drop in the abundance of invertebrates, most of which are insects. And many individual species and species groups are declining or even being threatened with extinction, from bumblebees in Europe and the United States to fungus weevils in Africa.

“I think all the indicators point to real problems with insect and invertebrates in decline across the world.” – Scott Black“The vast majority of studies that have come out in the last decade are showing a decline in populations or insect species or biomass, and we’re seeing that consistently whether in Germany or equatorial areas or the United States,” says Scott Black, executive director of the Xerces Society, an invertebrate conservation nonprofit. “I think all the indicators point to real problems with insect and invertebrates in decline across the world.”


Although these results are disturbing, they’re not definitive. In some cases, they could indicate issues facing specific insect species or characteristics of specific locations rather than an overarching trend. It’s entirely possible that some don’t even prove a local problem: The paucity of moths attracted to lights, for example, could be a matter of selective pressures that favor individuals that aren’t attracted to light.

Nevertheless, there are plenty of reasons to expect declines. Widespread use of insecticides is one obvious one. Others include habitat loss and degradation; declines in or disappearance of plants or animals that specific insects depend on for food and shelter; displacement by nonnative species; air, water and light pollution; the global spread of insect diseases; climate change; and even, says Wagner, nitrification due to fossil-fuel burning.

Read More: https://www.scientificamerican.com/arti ... stand-why/



More than 75 percent decrease in total flying insect biomass over 27 years
October 18, 2017, Public Library of Science

The total flying insect biomass decreased by more than 75 percent over 27 years in protected areas, according to a study published October 18, 2017 in the open-access journal PLOS ONE by Caspar Hallmann from Radboud University, The Netherlands, and colleagues.

Insects play a crucial role in ecosystem functioning, pollinating 80 percent of wild plants and providing a food source for 60 percent of birds. Previous research has shown an overall pattern of decline in insect diversity and abundance, but has focused on single species or taxonomic groups, rather than monitoring insect biomass over an extensive period.



Read more at: https://phys.org/news/2017-10-percent-d ... s.html#jCp


How Climate Change May Affect Winter “Weather Whiplash”


Wild swings from pipe-bursting cold to spring-like warmth seem to be on the rise

In the last few weeks, temperatures in the Midwest and Northeast have swung wildly from bone-chilling cold to unseasonably warm, in some places jumping more than 50 degrees Fahrenheit in the span of just a few days.

It’s a case of “weather whiplash”—a sudden shift from one set of weather conditions to another. And now, experts are questioning whether the changing climate may affect some kinds of winter whiplash events.


Read more: https://www.scientificamerican.com/arti ... -whiplash/

What Happens if the Magnetic North Pole Keeps Rushing Toward Siberia?

Earth’s north magnetic pole, a wandering point where magnetic field lines vertically enter and exit our planet, has been acting weird lately.

Some 20 years ago, the pole was moving at about 15 kilometers per year, from Canada toward Siberia. But its current clip is 55 kilometers per year, nearly four times faster. In 2018, it passed the International Date Line and entered the Eastern Hemisphere.

Because many navigational systems are based on accurate readings of magnetic north, this accelerated drift has captured the attention of scientists.


Read more: https://motherboard.vice.com/en_us/arti ... rd-siberia


ness31 wrote:I also wanted to start a thread about the polar bears invading Russian towns, but I find PoFo to be rather human centric lol..

Done, :coffee:
Last edited by RhetoricThug on 12 Feb 2019 17:49, edited 2 times in total.
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