Many forces work in concert with each other to create long term weather cycles and waves of extinctions. The great extinctions happen when several forces converge with catastrophic events such as meteorite strikes. There is no 'steady state' in nature but rather a see-saw effect. This is why humans are now tipping it increasingly in one direction is so dangerous.
BEIJING, Oct. 12 (Xinhuanet) -- Wobbles or variations in the Earth's orbit and tilt are associated with extinctions of rodent and mammalian species, Dutch scientists said on Wednesday in a study published in the journal Nature.
Dr. Jan van Dam from the Utrecht University and colleagues reached this conclusion after studying the fossil record of rodents from central Spain over a 22-million-year span, showing a link between rodent extinction events and the climate record.
"Extinctions in rodent species occur in pulses which are spaced by intervals controlled by astronomical variations and their effects on climate change," said van Dam.
They found two cycles corresponding to the disappearance of rodent species. One lasts 2.4 million years and is linked to variations in the Earth's orbit. The other is a 1.2 million year cycle relating to shifts in the tilt on the Earth on its axis.
The fact that our planet's moon is very large relative to the size of the planet as well as the fact that our planet is set at an odd angle to the sun and is rather shaky, one wonders if the cataclysmic event 3 or more billion years ago, the collision that created our moon, is still causing our planet's instability.
The instability of the earth is part of this planet's creative process. If something never changes, nothing ever changes. The dynamo which powers evolution is the constantly changing environment interacting with the ever-increasing interaction of all living things as creatures struggle to overcome constant changes.
Humans developed huge brains just to cope with the difficulties of a wildly swinging climate that switches from hot to cold with brutal suddeness.
As scientists study this dynamic system which is our planet, they discover more and more things influence the climate and these changes have varying effects on life forms and it is endless, how many things affect each other.
By RANDOLPH E. SCHMID, AP Science Writer 2 hours, 22 minutes ago
WASHINGTON - Dust storms swirling out of Africa's Sahara Desert may help reduce hurricane activity in the Atlantic Ocean, a new study suggests. The findings aren't conclusive, but researchers led by Amato T. Evan of the University of Wisconsin-Madison found that years with more African dust had fewer tropical storms and years with less dust had more storms.
The study is reported in Tuesday's issue of Geophysical Research Letters.
I hope they figure out the obvious: dust has a very big role to play in how storms form and what kinds of storms form. I remember one year, I think it was 1996, it was September and the sun was shining in the sky and the wind wasn't blowing from the north yet it was very cold for that time of year. So I put my hand over the sun and noted the sky had a very soft, pinkish color to it.
Looking at the news online, I discovered there was a huge dust storm in the Gobi desert. What I was seeing was the fine dust in the jet stream. Soon afterwards, we had some very ferocious snow storms. Last year in Asia, they had very ferocious snow storms and some of them had so much dust from the Gobi the snow turned pink.
Dust usually lowers temperatures. It is hard to see because the thin layer of dust is nearly invisible unless someone knows how to look for it but this dust does cut down on the amount of sun falling on the surface. We don't quite understand the dynamics of this except to say, dust can change climates such as during the Ice Ages when huge blankets of dust blew across the planet increasing the coldness. The great loess lands in Asia and much of the farm belt in the Midwest were built up by blowing dust.
This is probably how the planet regulates the environment: the dust from the deserts foils global warming by cutting down on sunlight.
That’s how the West works today: The monsoons cool the desert, as does the snowpack in the high country and the moisture transpiring from plants.
Shut off that mist and crank up the heat, and your lunch break may resemble the West of 2056.
That’s the word from University of Arizona climate scientist Jonathan Overpeck, who, along with other scientists from all over the West, made some thirsty predictions about the future of western Colorado in a series of speeches Wednesday and Thursday at a Mountain Studies Institute climate change conference at Fort Lewis College in Durango.
“Things are cooking in the West, and they’ll continue to cook even more,” Overpeck said.
The problem with the settlement of many millions of humans in desert environments is this is not a good idea in the long run. I lived in Arizona during my childhood and it was a lovely place, one which I am very fond of and whenever I visit, it sickens me, now humans are rapidly destroying the place.
It is not a good long-term place for humans to live as if they are in London or Manhattan. London and Manhattan are surrounded by or in close proximity to oodles of water and a culture of using this water wastefully has developed and then exported to places that are totally inappropriate. As I keep noting, the existance of toilets is a tremendously bad thing and alternative ways of dealing with human waste should have been instituted years ago except the hardest thing to change in a culture is customs.
Desert dwelling humans took few baths but would slather the body with oils to protect the skin and hide the scent of humans from game they were stalking just like dogs roll in the manure of their prey in order to hide the scent of the dog. But with modern styles of living, people use lots of water to hide the scent of being a human. All these factors means cities shouldn't exist in the desert. They are by their natures, inappropriate.
As for the various extinction cycles: without this, if we had a more stable environment, I doubt we would have had the long and amazing history of evolution. Especially for us humans. The incredible multi-level cycles within cycles that have created the present Interglacial/Ice Age events is what made us what we are today.
That and sexual selection.