Thursday, November 23, 2017

True “Social Cost of Carbon” Is More than Double Earlier Estimates, Study Finds

The true “social cost of carbon” is more than double earlier estimates — with even just an updated accounting of the agricultural sector on its own more than doubling earlier estimates in aggregate — according to a new analysis from the University of California—Davis and Purdue University.

Going on the new analysis, the true “social cost of carbon” is 72% to 129% greater than previously estimated following updated agricultural sector estimates.  In addition, the new analysis shows that climate change has an overall net-negative effect on agriculture; and that every ton of CO2 emitted currently causes up to $8.50 in costs on agriculture.

Also noteworthy is the analysis shows that higher temperatures have net-negative effects on 4 major crops in essentially all of the locations where they are grown.

An email sent to CleanTechnica provides more:  “This leads the overall social cost of carbon to increase from $8.60 per ton of CO2 to between $14.80 and $19.70, an increase of 72% to 129%. … Previous estimates were based on data from the 1980s and 1990s that suggested the short-term benefits of increased CO2 emissions on plant growth would benefit agriculture.  The updated estimates show that climate change has an overall negative effect on agriculture.

“Researchers analyzed more than a thousand published estimates of how crop yields from four global staples — wheat, rice, maize and soybean — respond to changing climate conditions.  The study found that higher temperatures have a negative effect on yields of all crops in almost all locations.  For example, temperature increases of 2° Celsius (3.6° Fahrenheit) result in average yield losses of 11% for maize and 26% for wheat.  These are only partially offset by the benefits from higher CO2 concentration, leading to net yield losses from climate change.

“The very early studies tended to show that the effects of warmer temperatures were not very severe and would be more than compensated by the beneficial effects of higher carbon dioxide concentrations,” explained lead author Frances Moore, an assistant professor in the Department of Environmental Science and Policy at UC Davis.  “Over the last few decades, as more work has gone into understanding how climate change might affect crop yields, science has found that hot temperatures themselves have large negative effects on crop yields.”

To expand on that — the new work found that a temperature rise of 2° Celsius (over pre-industrial levels) would cause economic losses of around 3% of the overall current value of the agricultural sectors in China and sub-Saharan Africa, 11% in Central America, 9% in the Middle East, 2% in the US, and 2% in Europe.

It should be remembered here that we are essentially now on a path that leads to at least 3° Celsius temperature rise by 2100 (and possibly far more than that) — to avoid such an outcome, vast changes to essentially all of the modern world’s systems will need to occur rapidly over just the next few decades.

The new study is detailed in a paper published in the journal Nature Communications.

Read more at True “Social Cost of Carbon” Is More than Double Earlier Estimates, Study Finds

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