According to a recent study, the planet has a "stabilizing feedback" mechanism that has been working for millions of years to maintain stable, habitable global temperatures.
Earth can regulate its own temperature
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Global volcanism, ice ages that cooled the planet, dramatic changes in solar radiation, and other factors have all contributed to significant changes in the Earth's climate. And yet, for the past 3.7 billion years, life has continued to beat, as per ScienceDaily.
MIT scientists have now confirmed in a study published in Science Advances that the planet has a "stabilizing feedback" mechanism that acts over millions of years to pull the climate back from the edge and maintain global temperatures within a constant, habitable range.
How exactly does it manage to do this? Silicate weathering, a process by which the gradual weathering of silicate rocks involves chemical reactions that eventually draw carbon dioxide out of the atmosphere and into ocean sediments, trapping the gas in rocks, is one potential mechanism.
Silicate weathering is thought by scientists to play a significant role in controlling the Earth's carbon cycle.
Silicate weathering's mechanism might act as a stable geological force to control carbon dioxide levels and global temperatures. But until now, there hasn't been any concrete evidence for the ongoing operation of such feedback.
Based on an examination of paleoclimate data that document changes in average global temperatures over the previous 66 million years, new findings were made.
In order to determine whether the data showed any patterns resembling stabilizing phenomena that controlled global temperatures on a geologic timescale, the MIT team applied mathematical analysis.
Scientists have previously observed hints of a climate-stabilizing effect in the Earth's carbon cycle, as chemical analyses of ancient rocks have demonstrated that the flux of carbon into and out of the Earth's surface environment has remained largely balanced despite significant swings in global temperature.
In addition, silicate weathering models suggest that the process should have some climatic stabilizing effects, as per MIT News.
The Earth's continued habitability also suggests that there is a geologic limit on extreme temperature fluctuations.
By examining data on global temperature fluctuations throughout geologic history, Arnscheidt and Rothman aimed to confirm whether stabilizing feedback had in fact been at work.
They used a variety of global temperature records compiled by other researchers, including preserved Antarctic ice cores and data on the chemical makeup of prehistoric marine fossils and shells.
Accelerating to a halt
The team used the data to apply stochastic differential equations, a mathematical theory that is frequently used to find patterns in datasets with a lot of variation.
In order to determine whether any patterns of stabilizing feedback emerged within each timescale, the team used this method to examine the history of average global temperatures over the past 66 million years.
They did this by looking at the entire period over different timescales, such as tens of thousands of years versus hundreds of thousands.
Interestingly, Arnscheidt and Rothman discovered that the data did not show any stabilizing feedbacks on longer timescales.
That is, on timescales longer than a million years, there doesn't seem to be any consistent cooling of global temperatures.
To put it another way, as the Earth's temperatures vary over longer periods of time, these variations might just be small enough geologically to fall within a range where stabilizing feedback, like silicate weathering, could occasionally keep the climate in check and, more importantly, within a habitable zone.
