In a new study, scientists insist that since the Earth’s highest biomass and biodiversity exist in the warmest regions, “higher temperatures than currently existing on Earth” and a “higher water content (absolute humidity) in the atmosphere” seem to be “more favorable” to the planet’s inhabitants.
Until a few thousand years ago, when mammoths and wild horses ate exposed grass year-round along the coasts of the Arctic Ocean, the Sahara was grass- and lake-covered, teeming with fish and megafauna and even ancient civilizations. These much-warmer periods were obviously more hospitable to plants, animals, and humans.
Image Source: LiveScience
In addition to being several degrees warmer, the Earth’s climate was also much more humid and rainforest-like during the Early Holocene, or up until about 5,000 years ago. Rainforests have far more biodiversity than cooler climates do, of course. This is likely why this period is referred to as the “Humidity Optimum” by geologists (Ramos-Roman et al., 2018).
Image Source: Ramos-Roman et al., 2018
In a new study (Schulze-Makuch et al., 2020), scientists acknowledge that the “highest biomass and biodiversity is present in tropical rainforests, and the least in cold polar regions.” Therefore, higher temperatures – about 5°C warmer than today – would be more “favorable” and “provide more habitable conditions.”
Unfortunately, we humans have not demonstrated we have the capacity to significantly affect the climate in recent decades, and thus we will continue to stand idly by as the Earth’s climate changes without us.
We are not mammoths, arctic horses, nor just SUV drivers.
Transaqua, to re-deploy water to Lake Chad will do in decades what millennia would do “naturally”.
China’s experience: Helping transform an African desert into a garden
https://news.cgtn.com/news/3d3d414d7855444e33457a6333566d54/index.html
And NAWAPA will do for the Great American Desert the same, using nuclear power.
NAWAPA XXI Animated Overview
https://www.youtube.com/watch?v=1NdKsZrG9RA
The financial oligarchy have succeeded in setting the narrative also for “skeptics”, who mostly still fall for the man-as-beast who must wait for rain and watch the desert growing. I have nothing against mammoths, and that 40,000 yBP grill found in Baja California must have had great steaks for weeks!
I think we have learnt from the Holocene’s climate meanderings, progress or perish.
Large-scale desalination with cheap fusion power, is also not a wooly mammoth’s primary concern, nor the financial oligarchy’s who have a great problem – they just cannot herd mankind into a corral .
The green Sahara had little to do with a warmer period in the Holocene. It was due to Milankovitch cycles. Due to changes in precession Northern Summer insolation was higher, the ITCZ was displaced north and the African monsoon reached the Sahara once a year allowing the existence of rivers, lakes and a savanna type of environment. This has been known since the 1980s.
We are now in a low Northern Summer insolation, but in about 9000 years the Sahara should become green again.
Javier
With rising CO2 the Sahara could green over sooner than that. It’s starting to already, slowly. This CO2 effect could be exerted independent of Milankovitch driven climate changes, although it would feedback into them of course as everything does.
https://ptolemy2.wordpress.com/2020/10/04/co2-fertilisation-and-the-greening-of-the-sahara/
The Sahara desert cut off subSaharan Africa from economic and technological developments around the Mediterranean, with lasting consequences. A greened over Sahara would profoundly change geopolitics and the status of Africa.
And in a decade Lake Chad will be refilled – from runoff water of large rivers with canals.
This Italian program has been delayed in Europe for 40 years – a colonial hangover.
China is in the program now. It was adopted as the only possible economic infrastructure plan for the region.
It will have profound consequences.
Phil,
Yes there is some CO2 induced greening at the arid and semi-arid regions of the planet, but the Green Sahara is something at a totally different scale. It is the arrival of the monsoon to a desert. It stops being a desert.
“It was due to Milankovitch cycles”
Milankovitch cycles are millennial in scale.
The greening of the Sahara occurred within a span of “a few centuries“, precluding its onset from being orbitally-driven. And yes, there is abundant evidence from many temperature reconstructions that Africa was multiple degrees warmer than today.
Kenneth
The Milankovitch forcing is the combination of eccentricity, obliquity and precession, the latter the shortest at 22 thousand years cycle time. It can and does change significantly over a few millennia. That’s why interglacials have an optimum with maximum temperature when Milankovitch forcing is at maximum. In our Holocene this was about 8000 years ago. Since then the Milankovitch solar forcing has declined slowly and temperature has declined with it. So the transition just 5000-2000 years ago to colder and more arid conditions, including the appearance of the Sahara Desert, is indeed a consequence of Milankovitch forcing.
Warmist climate revisionists / obscurantists are trying to oppose and obscure any climate forcing other than that of their deity, CO2 so they trot out the absurd argument that all climate change is caused by atmospheric factors only, usually volcanoes. These can either warm or cool climate as needed without the need of any evidence, just a hand waving solution for all historical climate change. The revisionists deny any role of the oceans or Milankovitch forcing. Or even of continental movement and rearrangement of ocean currents. It can only be atmospheric and CO2 related – no other climate factors are recognised. A dark age of “science” indeed.
“It can and does change significantly over a few millennia.”
That’s why I wrote the greening of the Sahara is unlikely to have been driven by Milankovitch. It went from desert to a lake-covered savannah within ~200 years.
The Northern Hemisphere warmed by 1K in less than 10 years and then warmed again by 1K in a few decades during the Late Antique Little Ice Age (~1500 years ago). That wasn’t Milankovitch either.
Nope. The start of the Holocene was also very abrupt at 11,700 BP and interglacials are also orbitally-driven.
Green Sahara periods are recurrent and have left their mark in the Mediterranean sapropels. These sapropels display orbital frequencies:
Green Sahara: African Humid Periods Paced by Earth’s Orbital Changes
“interglacials are also orbitally-driven”
And yet warmings of 8-16K within a span of decades (Greenland) that have global-scale signatures can occur due to “unforced oscillations”: https://www.sciencedirect.com/science/article/pii/S0277379118305705
Milankovitch cycles match up poorly with Antarctic temperatures (https://ars.els-cdn.com/content/image/1-s2.0-S1674987116300305-gr3.jpg) and bear almost no relation to NH ice core climate oscillations.
https://www.sciencedirect.com/science/article/pii/S1674987116300305
“Green Sahara periods are recurrent and have left their mark in the Mediterranean sapropels”
They are indeed recurrent but the timespan for the elicitation of such abrupt climate changes (~200 years) is too short to be consistent with millennial-scale forcings:
https://notrickszone.com/wp-content/uploads/2020/10/Green-Sahara-in-a-few-centuries-Kuper-and-Kropelin-2006.jpg
That’s not true either. The match is very good with a 6500 year lag.
https://i.imgur.com/fI1uUqZ.png
Non sequitur. A slow changing forcing can reach a tipping point producing an abrupt change.
Everybody knows interglacials are the product of Milankovitch forcing and everybody knows African Humid Periods are the product of Milankovitch forcing. There is no other known cause.
No, it’s not. And it’s not even close for the NH ice cores. The graph you provided even shows insolation peaks higher during glacials than interglacials in several instances. But it looks like we’ll have to agree to disagree that they “match”. And apparently it only needs to “match” in one hemisphere and not the other.
What was the “slow changing forcing” that caused temperatures to rise by 10-15C in Greenland in a span of 2-3 decades 20x during the last glacial…since this doesn’t align with Milankovitch?
And pointing out that abrupt, decadal-scale climate changes that do not align (at all) with insolation forcing is not a “non sequitur”.
We rose from the Pleistocene to the Holocene in less than a century ~11,700 years ago. Again, insolation forcing of ~0.1 W/m²/century doesn’t align with such an abrupt and profound change.
I welcome more warmth in my neck of the woods.I don’t function well when it is cold.
[…] Scientists Have Determined A 5°C Warmer Earth ‘Would Provide More Habitable Conditions’ […]
“Scientists Have Determined A 5°C Warmer Earth ‘Would Provide More Habitable Conditions’ “
Yes I agree, that would be so nice, not likely but would be nice.
Indeed getting a 1°C rise look to be struggling at the moment. Still it gave all the AGW types something to worry about.
Stefan Kröpelin, “Die Grüne Vergangenheit der Sahara” :
https://www.youtube.com/watch?v=JcsSHPjdsOo
the key matter is not the average temperature of earth, averaged over location and time of year, but rather the distribution of heat. If ocean currents carried more heat to the polar regions, that better for the world because the equatorial regions don’t particularly need it to be super hot, and the upper latitudes could benefit. The other key is rain fall. the tropic-sub tropic boundary is dry,
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