https://www.studyfinds.org/earth-natural-thermostat-climate/
Study: Earth Has A ‘Natural Thermostat’ To Regulate Climate During Extreme Temperature Swings
by Craig T Lee
PARIS — The possibility of controlling the Earth’s temperature has long led to various experiments by inquisitive scientists, but without great results. Now a recent study found proof for the first time ever of a natural thermostat that helps regulate the planet during extreme temperature swings.
British scientists say they’ve discovered that the preeminent mechanism that allows the Earth to recover from global cooling events is linked to the weathering of rocks. Rocks dissolve by rain and river water during the weathering process, and carbon dioxide is taken from the atmosphere to carbon-rich rocks in nearby waterways. When weathering runs its course, there’s a decrease in carbon dioxide on our planet.
The researchers examined rocks from about 445 million years ago, which matches out to the second largest extinction period in the planet’s history. Using samples from Canada and Scotland, the rocks showed that the global chemical weathering rate declined, which meant less carbon dioxide was removed and the climate was able to recover from the cool temperature.
“From looking at the relative abundance of lithium isotopes in ocean-derived rocks, we were able to confirm that chemical weathering is the driver of the Earth’s natural thermostat,” explains lead scientist, Dr. Philip Pogge von Strandmann, in a
news release. “When there is a warmer climate, there is more weathering, and when it is cooler there is less weathering: this is what you would expect, given that chemical reactions go faster with increasing temperature.”
The researchers had discovered evidence in earlier studies that showed weathering played a significant part in the Earth cooling down during periods of extreme heat, but the latest study proved just the opposite — when the planet experiences major cold spells, weathering slows and the “natural thermostat” allows the world to warm back up.
“This is the process that has allowed life to survive on Earth for around 4 billion years,” says Pogge von Strandman.
This study’s
findings were published in the June 2017 edition of the peer-reviewed journal
Geochemical Perspectives Letters.
Yeah--but none of that will save us. The planet--sure. It takes too long: "hundreds of thousands of years"
Here's another article about it:
https://phys.org/news/2017-08-proof-earth-natural-thermostat.html
Study gives first proof that the Earth has a natural thermostat
August 15, 2017, Goldschmidt Conference
New data provides the first proof that the Earth has a natural thermostat which enables the planet to recover from extremes of climate change - but the recovery timescales are significant. This work is presented today at the Goldschmidt conference in Paris, and has just been published in the peer-reviewed journal
Geochemical Perspectives Letters.
The idea of a natural temperature thermostat was first proposed in 1981, but until now no-one has been able to provide data to show that the recovery from the hot and cold temperature fluctuations were associated with a specific mechanism.
Now a group of British scientists has shown that recovery from global cooling events is associated with changes in the rate of
weathering of rocks, which is the main mechanism of removing CO2 from the atmosphere. In weathering, rocks are dissolved by rain and river water; the process removes CO2 from the atmosphere, which is then transported to the seas by rivers to be locked up in carbon-rich rocks such as limestone. The more weathering, the more CO2 is removed from the atmosphere.
The team had previously found evidence supporting the role of weathering in cooling the Earth in times of high temperature. This current work confirms that a slow-down of weathering takes place in cold periods, and so supports the concept of an "Earth thermostat".
The researchers were able to use the Lithium isotope ratios in rocks as a measure of weathering. They examined rocks from the period of the Hirnantian glaciation - around 445 million years ago - which correspond with the second greatest extinction of life in history, when around 85% of marine species were wiped out, due to the cooling and a dramatic drop in sea levels (estimated at around 80m) as water was locked into ice fields and glaciers.
The samples, which came from Anticosti Island (Quebec, Canada), and Dob's Linn (near Moffat, Scotland), show that global chemical weathering rate declined by a factor of four temporarily during the 5°C cooling that caused the glaciation, removing less CO2, allowing the climate to recover from the cooling.
Lead scientist, Dr Philip Pogge von Strandmann (University College London and Birkbeck, University of London) said:
"From looking at the relative abundance of lithium isotopes in ocean-derived rocks, we were able to confirm that chemical weathering is the driver of the Earth's natural thermostat. When there is a warmer climate, there is more weathering, and when it is cooler there is less weathering: this is what you would expect, given that chemical reactions go faster with increasing temperature. So more weathering removes CO2 from the atmosphere and puts a break on global warming. However, when the temperature cools, the reverse is true, and less CO2 is removed from the atmosphere in cold periods. This is the process that has allowed life to survive on Earth for around 4 billion years, and is what we are reporting in Paris".
Nevertheless, we need to be clear that the changes in temperature are gradual, and that recovery can take hundreds of thousands of years. Given the rapid increase in the rate of global warming at present, this kind of wait is not an option for us".
Commenting, Professor Jonathan Payne (Professor and Chair, Geological Sciences, Stanford University, CA, USA) said:
"The theory that chemical weathering provides a stabilizing feedback on Earth's climate goes back several decades, but observational confirmation of this hypothesis has been incomplete. In this study, Pogge von Strandmann and colleagues add a critical new piece of confirmation by using lithium isotopes to demonstrate a reduction in the chemical weathering rate associated with climate cooling - exactly the behaviour predicted if rates of
chemical weathering serve as a stabilizing feedback on climate. This study illustrates beautifully how new isotope proxy systems are enabling critical new tests of hypotheses both old and new and, in this case, confirming a theory that helps to explain why the Earth has enabled life to flourish continuously for more than 3.5 billion years".
Read more at:
https://phys.org/news/2017-08-proof-earth-natural-thermostat.html#jCp