I don't like to be a doomsayer, I usually focus on the positive side of things and the solutions rather than the problems, but today I came across an article that chilled my spine. Have you ever watched the movie The Day After Tomorrow? Well, scientific evidence is telling us that this science fiction movie can very soon become a reality. And you know what they say.. reality often surpasses our wildest imagination.
I have a degree in Oceanography, and although life took me down a different path, ever since my university days I've had a passion for the climate system and the impact us humans are having on the climate and biological systems.
The Science Behind
I remember when I was at university one of my projects was a study of the Climate period called the Younger Dryas, a cool period between roughly 12,900 and 11,600 years ago that disrupted the prevailing warming trend occurring in the Northern Hemisphere at the end of the Pleistocene Epoch.
This abrupt change in the climate was produced by an abrupt change in the Atlantic Ocean Circulation. Ocean and atmosphere are closely intertwined and ocean currents play an important role in regulating our climate. They transport the heat accumulated at the equator to northern latitudes contributing to a milder climate in the Northern Hemisphere.
So, during the Younger Dryas period, there was an abrupt change in the climate, from a warming climate after the last glaciation that had been ongoing already for a few thousand years, to an intense cooling period, or mini ice age, where climate conditions went back to those of the last glaciation. The reason scientists found for this abrupt change was that the warming climate had been producing for a long period intense melting of the Northern ice sheets. All this fresh water that poured into the north Atlantic ocean had been reducing the salinity of the water in the region weakening the AMOC (Atlantic Meridional Overturning Circulation). A weakened AMOC moves much slower and is less efficient in transporting heat and distributing it to northern latitudes.
AMOC's role in global climate systems and the potential impacts of its alteration
The Tipping Point: At a certain time scientists consider that the AMOC reached a tipping point (a point of no return where the system equilibrium collapses with devastating consequences). This turnover happened because the melting ice released a passage of water from lake Agassiz to the northern Atlantic ocean. The lake started pouring into the ocean, dramatically decreasing salinity, and pushing the already weakened AMOC over the tipping point. As a consequence, in a very short period of time (geologically speaking), barely 100 years, the Northern Hemisphere froze completely returning to the glaciation conditions, this cold period lasted over 1000 years, until the oceanic current system managed to find a new equilibrium state.
You see, all natural systems tend to an equilibrium state, and when we introduce a significant change in a system, the system will readjust itself (going through a chaotic period) until it finds a new equilibrium state. The chaotic period between the two equilibrium states was the Younger Dryas period.
*Note: Natural systems have the capacity to absorb changes, but if these are continuous, they accumulate until they reach a point where the system can't absorb it anymore. This point is the tipping point, a point where the equilibrium is broken and the system reacts to readjust itself to the change. Think of a bath that is filled with water, the bath tub absorbs every drop of water, but if the water reaches the rim of the tub, water will overflow, and keep overflowing until the water is once again below the rim. This is a very visual example of what a tipping point is.
Current Evidence and Implications: A new paper has now proved we are once again on the verge of reaching a tipping point in the Atlantic Meridional Overturning Circulation. And what has really surprised the scientists is the speed at which we are going there, due to the intense meltdown of the Greenland and Arctic ice sheets and the heating caused by human induced climate change. They estimate the point of no return could be reached anytime between 2025 - 2095. And even if it takes longer, it looks like it will be something inevitable.
The consequences will be devastating. Sea level will rise more than a meter in the North Western Atlantic coast, flooding major cities, and Climate in the Northern Hemisphere will cool dramatically. Do you recall the phrase: Winter is coming? Well, it'll be here sooner than we expected!
Solutions: There is no easy solution, but we can at least try. All efforts should go in accelerating, at a high speed, our transition to Net Zero Carbon emissions. This has to be our number one priority. But at this point, unfortunately, this won't be enough, and we will also need to implement as many systems as we can that will remove Carbon dioxide from the atmosphere, combining both artificial and natural methods. Some examples of natural methods for effectively removing CO2 from the atmosphere are seaweed farms, coral regeneration, ocean farming, restoring soil health, and restoring forests and rainforests in a big way.
This is not easy to reconcile with our current lifestyle. Major shifts need to be implemented at all levels. Climate Change is THE CHALLENGE of our time, and only time will tell if we will succeed or if we are forced to adapt paying a very high price for our unconsciousness.
Here’s the piece of news that caught my attention, published a few days ago in major news channels.
References:
For a deeper understanding of the scientific aspects of the AMOC, climate change, and their implications, consider visiting the following resources:
Nature.com Scientific Reports provides insights into the AMOC's decline and recovery under warmer climate scenarios, exploring the mechanics of heat and salt transport in the North Atlantic.
Science.org offers articles on early warning signals for the AMOC's collapse and the climate impacts of a weakened AMOC, highlighting the sensitivity of this oceanic circulation to freshwater forcing.
Scientific American discusses the potential shutdown of a mega ocean current like the AMOC, with new research suggesting an earlier collapse than expected.
NOAA Climate.gov talks about the uncertainties in changes to the AMOC, presenting different perspectives and recent findings.
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