CO2 level high­est in hu­man his­tory

USA TODAY International Edition - - FRONT PAGE - Ryan W. Miller and Doyle Rice USA TO­DAY

Car­bon diox­ide lev­els in Earth’s at­mos­phere hit a stun­ning mile­stone over the week­end.

Data from the Mauna Loa Ob­ser­va­tory in Hawaii showed that car­bon diox­ide lev­els sur­passed 415 parts per mil­lion Fri­day.

“We don’t know a planet like this,” Eric Holthaus, a me­te­o­rol­o­gist and writer at Grist, an on­line en­vi­ron­men­tal mag­a­zine, posted on Twit­ter.

Car­bon diox­ide (CO2) con­cen­tra­tions have sky­rock­eted far higher than any lev­els in more than 800,000 years, ac­cord­ing to data from the Scripps In­sti­tu­tion of Oceanog­ra­phy at the Uni­ver­sity of Cal­i­for­nia-San Diego.

“This is the first time in hu­man his­tory our planet’s at­mos­phere has had more than 415 ppm CO2,” Holthaus tweeted. “Not just in recorded his­tory, not just since the in­ven­tion of agri­cul­ture 10,000 years ago. Since be­fore modern hu­mans ex­isted mil­lions of years ago.”

Car­bon diox­ide lev­els mil­lions of years ago were higher than 2019 lev­els, but Earth’s tem­per­a­tures also were far higher. In the 800,000 years be­fore the In­dus­trial Rev­o­lu­tion, CO2 lev­els didn’t sur­pass 300 parts per mil­lion.

Homo sapi­ens didn’t emerge un­til about 300,000 years ago, and some of their pre­de­ces­sors were around about 2 mil­lion years ago.

CO2 is the green­house gas sci­en­tists say is most re­spon­si­ble for global warm­ing. When fos­sil fuels such as coal, oil and gas are burned to power our world, they re­lease CO2 and other green­house gases such as meth­ane. Those gases trap so­lar ra­di­a­tion in the at­mos­phere.

There is wide­spread sci­en­tific con­sen­sus that hu­mans caused the re­cent warm­ing in Earth’s at­mos­phere. In the past 20 years, the world’s tem­per­a­ture has risen about two-thirds of a de­gree Fahren­heit, the Na­tional Oceanic and At­mo­spheric Ad­min­is­tra­tion said.

Us­ing com­puter sim­u­la­tions along with pa­le­o­cli­matic data, a study this year from the Pots­dam In­sti­tute for Cli­mate Im­pact Re­search re­ported that car­bon diox­ide has reached lev­els in our at­mos­phere not seen in 3 mil­lion years.

Ralph Keel­ing, the di­rec­tor of the Scripps pro­gram that tracks CO2 con­cen­tra­tions, said in a state­ment: “The av­er­age growth rate is re­main­ing on the high end. The in­crease from last year will prob­a­bly be around three parts per mil­lion whereas the re­cent av­er­age has been 2.5 ppm.”

Since 1958, Keel­ing and his fa­ther, Charles David Keel­ing, have mea­sured car­bon diox­ide lev­els at the Mauna Loa Ob­ser­va­tory, and their work is re­spon­si­ble for cre­at­ing the Keel­ing Curve, a graph that shows CO2 ac­cu­mu­la­tions.

In May last year, CO2 con­cen­tra­tions reached 410 ppm.

A study from the Uni­ver­sity of Michi­gan found that CO2 emis­sions could soar to lev­els not seen in 56 mil­lion years by the mid­dle of next cen­tury.

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