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https://phys.org/news/2022-11-earth-temperature-millennia.html
The Earth's climate has undergone some big changes, from global volcanism to planet-cooling ice ages and dramatic shifts in solar radiation. And yet life, for the last 3.7 billion years, has kept on beating.
Now, a study by MIT researchers in Science Advances confirms that the planet harbors a "stabilizing feedback" mechanism that acts over hundreds of thousands of years to pull the climate back from the brink, keeping global temperatures within a steady, habitable range.
Just how does it accomplish this? A likely mechanism is "silicate weathering"—a geological process by which the slow and steady weathering of silicate rocks involves chemical reactions that ultimately draw carbon dioxide out of the atmosphere and into ocean sediments, trapping the gas in rocks.
Scientists have long suspected that silicate weathering plays a major role in regulating the Earth's carbon cycle. The mechanism of silicate weathering could provide a geologically constant force in keeping carbon dioxide—and global temperatures—in check. But there's never been direct evidence for the continual operation of such a feedback, until now.
The new findings are based on a study of paleoclimate data that record changes in average global temperatures over the last 66 million years. The MIT team applied a mathematical analysis to see whether the data revealed any patterns characteristic of stabilizing phenomena that reined in global temperatures on a geologic timescale.
They found that indeed there appears to be a consistent pattern in which the Earth's temperature swings are dampened over timescales of hundreds of thousands of years. The duration of this effect is similar to the timescales over which silicate weathering is predicted to act.
The results are the first to use actual data to confirm the existence of a stabilizing feedback, the mechanism of which is likely silicate weathering. This stabilizing feedback would explain how the Earth has remained habitable through dramatic climate events in the geologic past.
"On the one hand, it's good because we know that today's global warming will eventually be canceled out through this stabilizing feedback," says Constantin Arnscheidt, a graduate student in MIT's Department of Earth, Atmospheric, and Planetary Sciences (EAPS). "But on the other hand, it will take hundreds of thousands of years to happen, so not fast enough to solve our present-day issues."
More information: Constantin Arnscheidt, Presence or absence of stabilizing Earth system feedbacks on different timescales, Science Advances (2022). DOI: 10.1126/sciadv.adc9241
(Score: 2) by Rosco P. Coltrane on Friday November 18 2022, @07:39PM (3 children)
What I meant was, the Earth will return to some state that supports life of some sort. In other words, it'll reach a new normal. The weather going into a runaway reaction and either creating a superhot Venus-like cauldron, or going permanently cold and turning the planet into a snowball forever, will not happen. The only thing that'll happen is, the responsible species - and the innocent ones that are unsuited to the new environment - will die off, and then life will carry on in another form with a new equilibrium.
(Score: 4, Informative) by Immerman on Friday November 18 2022, @09:23PM (2 children)
> The weather going into a runaway reaction and either creating a superhot Venus-like cauldron, or going permanently cold and turning the planet into a snowball forever, will not happen.
It's *already* happened to every other planet in the solar system, and it's definitely in our own future within a few billion years as the sun heats up and boils away our oceans.
It's not a realistic risk of our current climate problems, but it's absolutely on the table long-term.
What is a real risk are the normal extremes of our planet - we're currently in an unusually long interglacial period, one of the most unstable states the planet is ever in, and there's only two ways that ends: the glaciers return, burying most of the middle latitudes in a mile or so of ice, leaving only the tropics horpitable, or we tip out of the Icehouse state the planet has been in for the last tens of millions of years into the planet's normal Hothouse state, which is 5-10C hotter and tends to feature lots of deserts, swamps, and jungles.
The latter is probably the choice to pick, but the transition tends to be environmentally devastating as species can't adapt fast enough, and it takes millenia for biodiversity to recover. And we're currently on track to push the transition far faster than it's ever happened before, which is likely to be far more devastating.
(Score: 0) by Anonymous Coward on Friday November 18 2022, @11:47PM (1 child)
Bb..ut can't we just move to Mars if that happens?
(Score: 1) by khallow on Saturday November 19 2022, @06:52AM