Health

Rising Carbon Dioxide Levels Will Reduce Nutritional Value of Crops

The effects of carbon dioxide put populations at risk of losing the available dietary protein in staple crops, compounding the challenges of poverty worldwide.

Aug. 31, 2017
By Isabel Putinja

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New research by Har­vard Uni­ver­sity warns that ris­ing car­bon diox­ide lev­els that con­tribute to global warm­ing could dras­ti­cally reduce the nutri­tional con­tent of sta­ple crops.

Researchers from Har­vard’s T.H. Chan School of Pub­lic Health who con­ducted the study have con­cluded that if car­bon diox­ide lev­els con­tinue to rise, the nutri­tional value of crops like wheat, rice, bar­ley and pota­toes will be reduced. This would put the pop­u­la­tions of 18 coun­tries around the world at risk of los­ing more than five per­cent of the dietary pro­tein avail­able to them by 2050.

This study high­lights the need for coun­tries that are most at risk to actively mon­i­tor their pop­u­la­tions’ nutri­tional suf­fi­ciency, and, more fun­da­men­tally, the need for coun­tries to curb human-caused CO2 emis­sions.- Samuel Myers, Har­vard Uni­ver­sity

In con­crete num­bers, this amounts to 150 mil­lion peo­ple. The researchers arrived at this fig­ure by study­ing the results of exper­i­ments con­ducted on crops by expos­ing them to high car­bon diox­ide lev­els and exam­in­ing global dietary infor­ma­tion, demo­graph­i­cal data and fig­ures mea­sur­ing income inequal­ity.

The study, pub­lished in Envi­ron­men­tal Health Per­spec­tives, revealed that when exposed to high lev­els of car­bon diox­ide, the pro­tein con­tent of rice decreased by 7.6 per­cent, 7.8 per­cent for wheat, 14.1 per­cent for bar­ley and by 6.4 per­cent for pota­toes. This also presents a risk of decline in the min­eral con­tent of these foods, like zinc, iron and sele­nium, all of which are essen­tial for human health.

Accord­ing to the study, 76 per­cent of the world’s pop­u­la­tion gets its pro­tein from plants. The regions high­lighted as the most vul­ner­a­ble include Sub-Saha­ran Africa where pro­tein defi­ciency is already a dilemma and South Asian coun­tries like India where rice and wheat are sta­ples and the main pro­tein source.

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In India, 5.3 per­cent of the pro­tein con­tent of crops could be lost, affect­ing 53 mil­lion peo­ple.

In a Har­vard Uni­ver­sity press release, Samuel Myers, senior research sci­en­tist at the Depart­ment of Envi­ron­men­tal Health stressed that action needs to be taken: This study high­lights the need for coun­tries that are most at risk to actively mon­i­tor their pop­u­la­tions’ nutri­tional suf­fi­ciency, and, more fun­da­men­tally, the need for coun­tries to curb human-caused CO2 emis­sions,” he said.

Strate­gies to main­tain ade­quate diets need to focus on the most vul­ner­a­ble coun­tries and pop­u­la­tions, and thought must be given to reduc­ing vul­ner­a­bil­ity to nutri­ent defi­cien­cies through sup­port­ing more diverse and nutri­tious diets, enrich­ing the nutri­tional con­tent of sta­ple crops, and breed­ing crops less sen­si­tive to these CO2 effects.”

Car­bon diox­ide is one of the heat-trap­ping green­house gases that con­tribute to cli­mate change. This was the first study to quan­tify the impacts of ris­ing car­bon diox­ide lev­els as a result global warm­ing on the pro­tein con­tent of sta­ple crops.

The researchers point out that adding more fer­til­izer to crops does not mit­i­gate the neg­a­tive effects of car­bon diox­ide on plant pro­tein, with fer­til­izer pro­duc­tion and uti­liza­tion actu­ally being a con­trib­u­tor to green­house gas emis­sions.

Replac­ing plant pro­tein with ani­mal pro­tein is not pre­sented as a solu­tion either because of the resource-inten­sive nature of live­stock farm­ing. Instead, more resilient crops like legumes could be an alter­na­tive, as well as mea­sures address­ing more equi­table food dis­tri­b­u­tion and poverty reduc­tion.



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