
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."
The study is co-authored by Arnscheidt and Daniel Rothman, professor of geophysics at MIT.
Stability in data
Scientists have previously seen hints of a climate-stabilizing effect in the Earth's carbon cycle: Chemical analyses of ancient rocks have shown that the flux of carbon in and out of Earth's surface environment has remained relatively balanced, even through dramatic swings in global temperature. Furthermore, models of silicate weathering predict that the process should have some stabilizing effect on the global climate. And finally, the fact of the Earth's enduring habitability points to some inherent, geologic check on extreme temperature swings.
"You have a planet whose climate was subjected to so many dramatic external changes. Why did life survive all this time? One argument is that we need some sort of stabilizing mechanism to keep temperatures suitable for life," Arnscheidt says. "But it's never been demonstrated from data that such a mechanism has consistently controlled Earth's climate."
Arnscheidt and Rothman sought to confirm whether a stabilizing feedback has indeed been at work, by looking at data of global temperature fluctuations through geologic history. They worked with a range of global temperature records compiled by other scientists, from the chemical composition of ancient marine fossils and shells, as well as preserved Antarctic ice cores.
"This whole study is only possible because there have been great advances in improving the resolution of these deep-sea temperature records," Arnscheidt notes. "Now we have data going back 66 million years, with data points at most thousands of years apart."
Speeding to a stop
To the data, the team applied the mathematical theory of stochastic differential equations, which is commonly used to reveal patterns in widely fluctuating datasets.
"We realized this theory makes predictions for what you would expect Earth's temperature history to look like if there had been feedbacks acting on certain timescales," Arnscheidt explains.
Using this approach, the team analyzed the history of average global temperatures over the last 66 million years, considering the entire period over different timescales, such as tens of thousands of years versus hundreds of thousands, to see whether any patterns of stabilizing feedback emerged within each timescale.
"To some extent, it's like your car is speeding down the street, and when you put on the brakes, you slide for a long time before you stop," Rothman says. "There's a timescale over which frictional resistance, or a stabilizing feedback, kicks in, when the system returns to a steady state."
Without stabilizing feedbacks, fluctuations of global temperature should grow with timescale. But the team's analysis revealed a regime in which fluctuations did not grow, implying that a stabilizing mechanism reigned in the climate before fluctuations grew too extreme. The timescale for this stabilizing effect — hundreds of thousands of years — coincides with what scientists predict for silicate weathering.
Interestingly, Arnscheidt and Rothman found that on longer timescales, the data did not reveal any stabilizing feedbacks. That is, there doesn't appear to be any recurring pull-back of global temperatures on timescales longer than a million years. Over these longer timescales, then, what has kept global temperatures in check?
"There's an idea that chance may have played a major role in determining why, after more than 3 billion years, life still exists," Rothman offers.
In other words, as the Earth's temperatures fluctuate over longer stretches, these fluctuations may just happen to be small enough in the geologic sense, to be within a range that a stabilizing feedback, such as silicate weathering, could periodically keep the climate in check, and more to the point, within a habitable zone.
"There are two camps: Some say random chance is a good enough explanation, and others say there must be a stabilizing feedback," Arnscheidt says. "We're able to show, directly from data, that the answer is probably somewhere in between. In other words, there was some stabilization, but pure luck likely also played a role in keeping Earth continuously habitable."
This research was supported, in part, by a MathWorks fellowship and the National Science Foundation.
Reader Comments
" Prove it " , such a conceited attitude if ever there was one.
I for one have given facts and evidence to support my observations.
I believe its time for those who languish in their own self-importance and ignorance to get off their lazy backsides and get a grip as to what is actually go on and stop being so indifferent.
Some variation but basically the same.
We were supposed to be underwater what 30 years ago?! LMAO!
That being said I know that the real scientist not the gubmint political variety are sayin ice age coming. Exact opposite of the political science
Problem solved.
Personally I am more worried about pollution than climate change.
Climate isn't static. It changes. It has NEVER been static.
The one thing that is static is humankind's pretentiousness and hubris.
You might want to rethink that one.
if you are trying to convince me that your point of view is more wise, and the only one people should have, please include the reasons why you think i should be very very worried about climate change.
i am not being persnickety. just wondering what your thoughts are.
mine are pretty much that people are greedy little parasites that will never stop wanting more, while the "green energy" schtick will not do a lot for the climate as you still need fossil fuels to manufacture the "green energy" products (at least the mining)
and green energy production is at least as polluting, if not more so than carbon based energy. you'd still need fossil fuels for shipping, you'd still need fossil fuels for aviation, you'd still need fossil fuels for the war machine, you'd still need fossil fuels to mine for other base metals, you'd still need fossil fuels for forging the base metals, you'd still need fossil fuels for most production.
unless you switch to nuclear power, but that can be very polluting as well. some of those isotopes have thousands of years half life.
green energy production pollutes groundwater just like fracking.
green energy will never be able to allow people to have as much as they want of the things that they want without hardships whilst not producing great amounts of pollution through it's creation.
oil will never be replaced as a raw building block of consumer goods, pharmaceuticals, and food additives/preservatives, even if "green energy" is used to produce it.
therefore you cannot untangle carbon from society even if you tried. (carbon, being the main supposed culprit of climate change)
no matter where you get your energy from there is pollution tied to it, great amounts of pollution.
if people are gonna put up with hardships for supposedly less climate change, while still polluting almost the same amount, if not more so through radioactive isotopes and non recyclable components, while still demanding all of their consumer goods,,,,,
i choose the hardship of climate change instead of the increased pollution of "green energy".
i really prefer humans living modestly and in harmony with the earth, without polluting it or yearning for way more than they need, but since that's never gonna happen i wouldn't bitch if climate change kills off a bunch of us, even if i and or my family are included.
the hardships of climate change would lower the mass pollution of billions upon billions of parasitic humans.
i am not for an "elite" class culling humans so they can remain in power, controlling everything while living opulently and being dictators to everyone else in a lower class like kings on the hill with the power to dictate who lives or dies, or how they live, but i have NO problem with nature taking that roll.
call me stupid, call me strange.
there's my point of view which is thoroughly thought through.
apologies for anything that sounds offensive and i hope i explained my point of view well enough.
I'm going to sound overly simplistic here but not deliberately done.
I grew up in the late 50's steam trains, open fires , coal powered power stations and very crude cars and yes we had smog, but take it back a few hundred years and things would have been worse.
I live in a village today and yes I burn wood and coal in my fire at home.
I don't believe that there is today a model that's can reliably suggest what actual damage was incurred to earth's atmosphere during these times.
It be interesting also to consider the volume of exhaust that was contributed to earth's atmosphere via volcanoes during this period.
Advanced technologies have to some extent cleaned air born pollutants but as technologies Advanced what was the cost?
I watched a program yesterday on how wind turbines are manufactured and installed, considering the manufacturing and installation footprint against potential energy savings and given a life expectancy of 30 years max, the footprint to development, manufacture, install and decommission do massively out way any benefits of the project to save our planet via greener credentials.
So to some extent that addresses other sources of energy generation, as in nuclear and fracking.
Up front all is very green but considering all thats involved, it's far from it.
The worst polluters in the car market are Hybrids, yes Hybrids not diseals as the government's would have you believe.
The Green revolution isn't green, nor is it environmental friendly or cost effective in the long term.
If the British government was to open up old coal fired power stations with clean burn technology, Britain would be self sufficient in energy, recreate jobs and communities and more importantly, it WOULDN'T put a dent in earth's atmosphere.
Now earth's natural cycles are a different matter, not influenced by man, cow or CO2, they are being used and hijacked to establish unwarranted narratives that are NOT beneficial to mankind or our planet.
So thats my view point, I'd welcome your comments.
I watched it and was AMAZED as to the unhealthy footprint and cost of technologies that go into making clean energy.
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im not against "green tech".
i just wish that it was improved vastly before so many resources were poured into it's implementation to limit the pollution and disruption of the environment to achieve a desired effect.
the only thing i would really have a difference of opinion on is the wind turbines.... they last UP TO 30 years tops, if no bad weather events happen that over drive them, among other ill fated factors.
i am kind of busy, if i think of something else constructive to add i will get back to you. much respect and many thanks for your reply!!
I'm no scientist but i know indoor growers inject co2 into their closed enviroments to feed plants. The warmer the closed enviroment the more c02 injected. Plants love it. So that suggests to me the closed loop they set out to prove is the oposite of their bias conclusion. As the atmosphere temps rise, more c02 is released which feeds the plants, makes them grow faster and release o2 which in turn cools the atmosphere. Thats my thoughts and observations.
Non-compliance is the only way out of this mess - on an individual level refuse to comply with rules that make no sense and don't trust the effing experts part of the coalition of liars been around too long and told one lie too many....some ideas die hard and the 20th century needs to be placed in the dustbin of history for all the bad idea perpetuated by those causing needless suffering of innocence.
I'm aware of the solar cycles. Ice ages etc.Time will tell.
I've learnt more from the age of 50 than I ever did at school, midst they taught a boat load of BS then
Earth is getting ready for a cool down.
Also I am basing what i have said off of AGW theory not global cooling.
but i still despise the amounts of pollution humanity creates, even if earth IS cooling.
still i am not worried. no matter what happens to humanity, i would like what is left of the world to not be devastatingly polluted for whatever comes next.
That's what I'd call burying things under the carpet and not very eco-freindly.
I came from a mining community, pits were everywhere, coal was king and times were hard.
I was taught how to light the fire and maintain it efficiently and how to clean it out afterwards, I always remember having to take the pan of ashes outside and sprinkle them on top of my dad's vegetable plot, now that's what I'd call recycling.
History does not attest to that statement if you look back at how many Galactic Glaciers we've had.