Climate Letter #1244

How the effects of malnutrition caused by the rise in CO2 levels are distributed.  Declines in key nutrients have already been established.  This new study shows which populations will be most affected because of the nature of their diets.  A colored map is included in this post that sorts the information by scaling.  While the study draws attention to a possible CO2 level of 550 ppm, the trends toward those goals are in effect today. “The growing body of literature on the impacts of rising CO2 concentrations on the nutritional quality of our food indicates the health consequences could be significant, particularly for poorer populations in Africa and Asia – although everyone could be affected.”

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A current CO2 update.  The increase for the past twelve months has been almost exactly 2 ppm, an amount that has been consistently in place all of this century except for the bulge in the 2015-16 El Nino event.  There is no sign of either a slowdown or acceleration at this moment.  At this rate 550 ppm would not show up for 70 years.  Also, the much talked-about double from the preindustrial level of 280 falls into view soon after, or right near the end of the century.  Be sure to check out the bottom chart at this link, due for a seasonal turnaround in just one month at about the 403 level.

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An article about climate warming feedbacks.  The author, who began studying this activity in the 1980s, wrote this in response to the recent major study on long-term feedbacks that has received so much attention.  His article has a number of links that are worth opening and reading, including one on the water vapor feedback that deserves some comment.  Andrew Dessler and colleagues established the strength of this feedback in 2008, as reported here by NASA.  Quoting Dessler, “We now think the water vapor feedback is extraordinarily strong, capable of doubling the warming due to carbon dioxide alone.”  The implication, which is not always recognized as well as it should be, is that the same effect applies to any source of warming, whatsoever, not just CO2 and other greenhouse gases.  That includes the impacts of any an all albedo changes.  And it works in a corresponding way for everything in the reverse direction.  Water vapor even reacts to its own warming effect, which I believe has been netted out in the doubling total that Dessler refers to.  Of course water vapor has its own timetable for moving into place, which is referred to by the concept of relative humidity, exhibiting a set of irregularities that seem to average out over time at about 60% of what is possible.

–The 2008 water vapor report:  https://www.nasa.gov/topics/earth/features/vapor_warming.html

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