How the climate can rapidly change at tipping points
During the last glacial period, within only a few decades the influence of atmospheric CO2 on the North Atlantic circulation resulted in temperature increases of up to 10 degrees Celsius in Greenland – as indicated by new climate calculations from researchers at the Alfred Wegener Institute and the University of Cardiff. Their study is the first to confirm that there have been situations in our planet’s history in which gradually rising CO2 concentrations have set off abrupt changes in ocean circulation and climate at “tipping points”. These sudden changes, referred to as Dansgaard-Oeschger events, have been observed in ice cores collected in Greenland. The results of the study have just been released in the journal Nature Geoscience.
Previous glacial periods were characterised by several abrupt climate changes in the high latitudes of the Northern Hemisphere. However, the cause of these past phenomena remains unclear. In an attempt to better grasp the role of CO2 in this context, scientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) recently conducted a series of experiments using a coupled atmosphere-ocean-sea ice model.
First author Xu Zhang explains: “With this study, we’ve managed to show for the first time how gradual increases of CO2 triggered rapid warming.” This temperature rise is the result of interactions between ocean currents and the atmosphere, which the scientists used the climate model to explore. According to their findings, the increased CO2 intensifies the trade winds over Central America, as the eastern Pacific is warmed more than the western Atlantic. This is turn produces increased moisture transport from the Atlantic, and with it, an increase in the salinity and density of the surface water. Finally, these changes lead to an abrupt amplification of the large-scale overturning circulation in the Atlantic. “Our simulations indicate that even small changes in the CO2 concentration suffice to change the circulation pattern, which can end in sudden temperature increases,” says Zhang.
Further, the study’s authors reveal that rising CO2 levels are the dominant cause of changed ocean currents during the transitions between glacial and interglacial periods. As climate researcher Gerrit Lohmann explains, “We can’t say for certain whether rising CO2 levels will produce similar effects in the future, because the framework conditions today differ from those in a glacial period. That being said, we’ve now confirmed that there have definitely been abrupt climate changes in the Earth’s past that were the result of continually rising CO2 concentrations.”
The Latest on: Abrupt climate changes
- Reduced Sulfur Emissions Could Cause Climate Shockon August 4, 2022 at 10:00 am
When we talk about emissions these days, we typically talk about cutting them back for the good of the environment. However, the climate system is a complex beast, and one we’re still ...
- Climate Change: An Inconvenient Deception -- Fossil Fuels are Green Energy!on August 1, 2022 at 12:00 am
This article will explain based on long-held and recent scientific findings: (1) why fossil fuels are not causing global warming/climate change; (2) that fossil fuels are actually green energy that ...
- Editorial: Surprise Senate deal on climate change should be only the beginningon July 29, 2022 at 3:00 am
The reversal, just weeks after Sen. Joe Manchin shot down similar legislation, is a ray of hope after years of inaction.
- Schumer-Manchin reconciliation bill has $369 billion to fight climate change — here are the detailson July 28, 2022 at 7:03 am
The legislation, called the “Inflation Reduction Act of 2022,” provides $369 billion for climate and clean energy provisions, the most aggresive climate investment ever taken by Congress.
- EDITORIAL: Climate change, drought signal time to go against the greenon July 27, 2022 at 4:28 am
City and state lawmakers should build on the idea by creating local and state incentives to remove existing yard lawns and replacing them with low-water and no-water alternatives.
- Hold the mustard: French suffer unexpected loss to climate changeon July 22, 2022 at 5:30 am
Celia Rivenbark humor column states sympathy for French mustard shortage, suggests using Duke's mayonnaise or eastern NC barbecue sauce.
- No Republican senator supported a climate plan – where is the party on the issue?on July 22, 2022 at 12:35 am
The party has largely abandoned its past climate denialism, but experts and activists say the ideas Republicans have proposed are insufficient or misguided When Joe Manchin announced an abrupt end ...
- The bigger the temperature change, the larger the extinction event, reveals researcheron July 21, 2022 at 5:00 pm
The research was published in the journal Biogeosciences on July, 22, 2022. Abrupt climate change, accompanied by environmental destruction from large volcanic eruptions and meteorites ...
- Putnam, Hall and Allen awarded $600K NSF grant for glacier researchon July 20, 2022 at 8:06 am
Understanding how winters and summers evolved is therefore important for diagnosing the causes of abrupt climate change — and understanding how the North Atlantic seasonal cycle responds to ...
via Google News and Bing News