A novel study published in Science Advances by MIT researchers indicates that the Earth has a "stabilizing feedback" method that functions over hundreds of millions of years to bring the climate back to the brink of disaster, maintaining temperature increases within a stable, livable range. Earth is capable of regulating and stabilizing its temperatures across huge durations - 100,000 years or more on average - even after severe swings in climate produced by ice ages, radiation from the sun variations, and extreme volcanic activity.
To achieve the findings of the research, a possible explanation is "silicate weathering," a geological process that involves chemical processes that eventually suck carbon dioxide away from the atmosphere and then into ocean sediments, storing the gas in rocks.
Scientists have long hypothesized that silicate weathering has a significant impact on the Earth's carbon cycle. This process of silicate weathering may offer a geologically consistent drive in regulating carbon dioxide - hence world temperatures, as described by Science Alert. However, until now, there has been no direct evidence for the continuous operation of such feedback.
Stabilizing Feedback Describing Earth's Stability
The new conclusions are based on an examination of paleoclimate data, which documents variations in global average temperatures over the previous 66 million years. The MIT team used mathematical analysis to see if the data revealed any patterns resembling stabilizing phenomena that kept global temperatures stable over geologic time. The researchers discovered that there appears to be a persistent sequence in which the Earth's temperature changes are dampened throughout hundreds of thousands of years. This effect's duration is comparable to the timescales predicted for silicate weathering.
The findings are the first to use real-world data to prove the existence of a moderating feedback process, most likely silicate weathering. Such stabilizing feedback might describe how the Earth has stayed livable throughout geologic time despite severe climatic upheavals. On the one hand, it's excellent because the scientists know that today's global warming will be offset by this stabilizing feedback, according to Constantin Arnscheidt, a Ph.D. candidate from the MIT's Department of Earth, Atmospheric, and Planetary Sciences (EAPS). However, it will require many thousands of years to occur, which is not fast enough to fix our current problems.
Scientists have already discovered evidence of a climate-stabilizing impact in the Earth's carbon cycle: chemical examinations of rock formations have revealed that the movement of carbon into and out of the Earth's surface environment has stayed reasonably balanced, despite enormous fluctuations in global temperature. Additionally, silicate weathering models anticipate that the process will have some stabilizing influence on the global climate. Moreover, the fact that the Earth has remained habitable suggests that there is some intrinsic, geologic control on excessive temperature changes. As per Arnscheidt, one idea is that researchers need some kind of stabilizing mechanism that sustains temperatures adequate for life. However, research has never shown that such a system has consistently governed the Earth's climate.
Global Temperature Swings
By examining data on global temperature changes across geologic time, Arnscheidt and Daniel Rothman attempted to prove the existence of stabilizing feedback. They worked with a variety of global temperatures obtained by other scientists, including the chemical makeup of prehistoric marine fossils including shells, along with conserved Antarctic ice cores.
The researchers have used the mathematical theory of stochastic differential equations to the data, which is typically used to identify patterns in wildly changing datasets. Using this method, the researchers examined the record of global average temperatures over the previous 66 million years, analyzing the entire period across different durations, such as millennia vs hundreds and thousands, to see whether any tendencies of stabilizing feedback appeared.
Without stabilizing feedback, global temperature swings should increase over time. However, the team's investigation identified a zone in which fluctuations didn't develop, meaning that the climate was stabilized before variations were too excessive. The timeframe for such a stabilizing effect - hundreds of thousands of years - corresponds to what scientists expect for silicate weathering.
Remarkably, Arnscheidt and Rothman discovered that on longer timeframes, the data did not disclose any stabilizing feedback. Such that, there does not seem to be any periodic cooling of the global average temperature on durations greater than one million years.
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