The Ocean status is ready for the next big cooling,
which is the real threat for mankind.
Post: 16th August 2018
In a previous post we discussed Younger Dryas cooling about 13,000 years ago. Another dramatic cooling occurred at ca. 8,200 y B.P. in the Early Holocene that was triggered by the glacial drainage of freshwater into the North Atlantic and is recorded in multiple climatic archives across the globe. Frequently this side discussed substantial man-made weather and climatic changes during the two World Wars 1914-1918 and 1939-1945 (for 1939/40 see Fig. 3), MORE; and is convinced – based on strong facts – that shipping and other ocean uses by man has significantly contributed to global warming during the last 150 years (Fig. 5, 6), more HERE.
Now 16 eminent scientists published a study in the Proceedings of the National Academy of Science – PNAS August 6, 2018 – titled: “Trajectories of the Earth System in the Anthropocene” mentioning the ocean and seas -except as CO2 sink – not with one word. Instead they talk big about our planet at risk of heading towards an irreversible “Hothouse Earth” state. The abstract opens with the statement
We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a “Hothouse Earth” pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene.
Eventually the authors consider ten natural feedback processes they regard are as “tipping elements” that lead to abrupt change if a critical threshold is crossed, naming permafrost thaw, loss of methane hydrates from the ocean floor, weakening land and ocean carbon sinks, increasing bacterial respiration in the oceans, Amazon rainforest dieback, boreal forest dieback, reduction of northern hemisphere snow cover, loss of Arctic summer sea ice, and reduction of Antarctic sea ice and polar ice sheets. The authors shows that they lack any clue on how the global climate system works, and that the oceans are – next to the sun – the decisive driver of the weather system and climatic change events. That is shocking and undermines any hope that climatology will understand human impact on the Earth system, and whether man risks contributing to a HOTHOUSE or COLDHOUSE, any time soon.
Not less shocking is the observation that the study by the team of 16 international scientists (Will Steffen, et al.) was merely dismissed partly for “that there was no new science here”, but not therefore that the highly evident impact of the ocean is entirely ignored (see above). Even such highly attentive critics as Prof. Judith Curry, seems far away of addressing the serious deficiencies of the study, merely remarking in her post at (excerpts from “JC reflections”)
If the paper wasn’t so heavy on the policy prescriptions, it would be a much more credible contribution. //cont.
For almost a decade, I have been arguing that we need to articulate the possible worst case scenario for climate change. Such an articulation would take climate science beyond the restrictions of climate models to understand how the climate system works in terms of interacting feedbacks and also abrupt climate change. We need to bring more discipline (and creativity) to this interesting and important endeavor.
That is by far too little. At least Prof. Judith Curry is right that more efforts are needed “to understand how the climate system works”. But this requires immediate recognition of the major role of the huge and extreme cold water masse contained in the oceans and sea concerning weather and climatic matter, and profound and thorough research about the historic events (e.g. naval war changed climate), present (shipping, fishing and other ocean uses) and future human ocean activities that may influence climate change.
Post by Dr. Arnd Bernaerts, August 16, 2018
Study Summary – THE GUARDIAN – John Abraham, Wed 15 Aug 2018 11.00 BST; “Humans are pushing the Earth closer to a climate cliff”