Earth's Hidden Climate Regulator Could Trigger Timely Ice Age
The Earth might react to the vast amount of carbon dioxide (CO2) we are releasing into the atmosphere by overcompensating for this imbalance. This could mean that the anticipated ice age could occur as expected, rather than being postponed by tens of thousands of years.
It appears that there is a newly discovered 'regulator' that effectively buries large amounts of carbon beneath the sea floor. This process could potentially neutralize human-produced carbon emissions in a span of 100,000 years - a much quicker rate than previously assumed.
A Look at the "Lazy Regulator"
Previously, scientists believed that a 'lazy regulator' was responsible for locking away carbon over a period of 500,000 to one million years. However, new research indicates that there are actually two 'regulators' at work, which might mean that the coming ice age could begin as scheduled, rather than being held off due to climate change.
However, this newly discovered regulator does not shield us from the immediate impacts of global warming. It does not imply that we will be safe from the effects of climate change in the next 100 or even 1,000 years.
Understanding Earth's Climate Regulation
Since the 1980s, scientists suspected that the Earth has a way of balancing its climate over geological timescales. This is through a mechanism called the 'silicate weathering feedback'. This process involves rain capturing CO2 from the air and spraying it onto silicate rocks, which constitute about 90% of the Earth's crust. The CO2 reacts with these rocks, dissolving them, and forming molecules that are washed into the ground and eventually end up in the ocean. Here, the CO2 transforms into limestone and chalk, effectively locking it away for millions of years.
The silicate weathering feedback acts like a regulator because the warmer the Earth gets, and the more CO2 there is in the atmosphere, the water cycle intensifies. This results in more CO2 being transferred to the ocean, bringing atmospheric CO2 back to baseline levels.
This feedback mechanism works both ways. If the Earth gets too cold, and CO2 levels are too low, then the regulator consumes too little CO2 compared to the constant release of CO2 from the Earth's mantle, volcanoes and other magma features. In this scenario, less CO2 ends up in the ocean, and atmospheric levels slowly increase back to average.
Unexplained Climate Events
However, the silicate weathering feedback is slow and can take up to one million years to rebalance CO2 levels after a disturbance. This means there are climate events it cannot explain, including Earth's glacial and interglacial cycles, which are characterized by massive fluctuations in CO2 levels and temperatures that occur roughly every 100,000 years.
Discovery of a Second "Regulator"
Recent research was inspired by the calculation of how much organic carbon was preserved in ocean sediments during past climate events. The findings showed that after periods of intense volcanic activity and warming, large amounts of organic carbon were deposited onto the sea floor. This indicates a relationship between atmospheric CO2 levels and organic carbon burial in the ocean.
Combining this with the existing knowledge, a single global climate carbon cycle model was created that accounted for organic carbon burial in the sea floor. The results revealed a second 'regulator' that is rooted in the Earth's phosphorus cycle.
The Phosphorus Cycle
Weathering of rocks due to rainfall releases phosphorus, which eventually ends up in the ocean. There, this key nutrient is used by tiny photosynthetic creatures known as phytoplankton. When these creatures die, they sink to the bottom of the ocean, depositing organic carbon, phosphorus, and other nutrients.
In a warmer world, more phosphorus is washed into the ocean, leading to a proliferation of phytoplankton. This results in more organic carbon and phosphorus being deposited on the sea floor.
Organic Carbon Regulator: The "Supercharged" Regulator
This process leads to a boom in phytoplankton, which absorbs more and more CO2 from the atmosphere and deposits more organic carbon onto the sea floor, thereby reducing global temperatures. So, the warmer the world gets, the more productive the oceans become, and more carbon is locked away, cooling the climate.
However, the Earth can "overcorrect" in the meantime, triggering extreme events. It's uncertain how this second regulator will respond to current climate change, but it's unlikely that the Earth will be completely covered in ice.
Instead, it's possible that this 'organic carbon regulator' might compensate for the delay anticipated for the next ice age. Climate change is disrupting Earth's natural cycles, potentially pushing back the next ice age, which is due in about 11,000 years, by tens of thousands of years. But if this organic carbon regulator activates, atmospheric CO2 could return to baseline levels much faster, ensuring that the next ice age arrives on time.