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To explain Younger Dryas cooling look at what modern ocean uses
is contributing to climate change
About 13,000 years ago, the warming out of the last ice age temporarily reversed course around the North Atlantic. This cold “Younger Dryas” period lasted almost 2,000 years. Fig. 1. Like most climate events that primarily affect the North Atlantic region, ocean circulation is the prime suspect, starts a recent article by I.D. Keigwin et al. (Nature Geoscience). Indeed, any huge input of water in the ocean wills inevitable change the temperature, salinity and subsequently the horizontal and vertical current. A high volume influx of meltwater can jam regional or global ocean circulation. The consequence is a climatic change, for example the Younger Dryas cooling. That is what the paper is talking about (summarized HERE) .
Discussing big climate changes in a similar context is by far not new, with little avail. Too remote is overriding influence of the ocean on any change taken into account. Due to its cheer size low average temperature of mere +4°C, and variation in salinity, its relevance in the climatic system is 1’000 times bigger than of the atmosphere. A comparable very small water body of meltwater, cold and salt free, can easily trigger a very substantial drop of air temperature and an ice age. If the mentioned research concludes that melting water was “most probably the trigger” for the Younger Dryas cooling, it avoids discussing the ocean issue. Why? Is it a too big issue? Are too little data available? What could be done to overcome this problem?
A number of similar papers show the same short comings. In 2010 Andres E. Carlson discussed “What caused the Younger Dryas cold event?” , respectively Xu Zhang, 2014 “Has the puzzle of rapid climate change in the last ice age been solved?” Both mention remotely a slowing of Atlantic circulation, but remain far away from linking the periods of ice ages to the overriding structure of the oceans that can easily be triggered by numerous causes climatic changes, for example: meltwater, earthquakes, meteorites and so on. That is difficulty to assess after ten thousand, several hundred thousand or millions years, as ocean circulation is changing, leaving no direct record.
Does that prevent progress on understanding the impact of the ocean structure on climate change? It does not! Science need not more to do than investigate the impact of ocean activities at and in the sea. Shipping, fishing, off-shore industry, and other activities have an immediate profound effect on the temperature and salinity structure in the upper sea surface level. Those are not peanuts if one has to talk about many 100 Millions of nautical miles per day. Down to 10 meters the sea surface is mixed, leaving a wake that changed the temperature and salinity structure. Science does not even see that this is a serious contribution to global warming over the last century.
While general sea activities alter the ocean structure very slowly, mankind has shown that it is able to act also very forcefully over a short period of time. It did so during the two World Wars 1914-18 and 1939-45. In both cases the global climate changed course over few decades. Science needs only to pick up the challenge to explain the global warming after WWI and the global cooling from about 1940 to the mid-1970s. (more HERE) That research would enable science for better understanding historical drastic temperature jumps, but also understand urgently that
Industrial and leisure activities at sea is a serious contributor to Anthropogenic Global Warming (AGW),
How easily man can influence weather and climate, and
The most dramatic threat to men is global cooling from the vastness and depth of the oceans, which can come quickly and with ice age temperatures the current civilization can hardly cope with.
Excerpts from: https://www.iceagenow.com/Looming_Threat_of_Global_Cooling.htm
__Post 25. May 2010 – “Dr. Don Easterbrook, Professor of Geology at Western Washington University in Bellingham, WA.
_About 12,800 years ago we plunged into the Younger Dryas, said Easterbrook. When we came out of the Younger Dryas, temperatures again shot upward, rising 15 degrees in just 40 years.
_”Expect global cooling for the next 2-3 decades that will be far more damaging than global warming would have been,” says Easterbrook. “Twice as many people are killed by extreme cold than by extreme heat.”
A dangerous thesis: “Forget human influence.
Cooling and warming are both natural” – Dr. Don Easterbrook
READ Letter | Published: : E. Maier et al,
North Pacific freshwater events linked to changes in glacial ocean circulation, Nature (2018). DOI: 10.1038/s41586-018-0276-y