CO2 hits his­toric high

For 57 years the sci­en­tists high up on the rocky slopes of Mauna Loa moun­tain in Hawaii have been dili­gently mea­sur­ing at­mo­spheric car­bon diox­ide con­cen­tra­tions, but on May 9 they saw some­thing no hu­man has ever seen be­fore – a CO2 con­cen­tra­tion of over 4

Element - - Planet -

Just over 200 years ago, at the be­gin­ning of the in­dus­trial rev­o­lu­tion, the con­cen­tra­tion of CO2 in our at­mos­phere was just 280ppm. Ear­lier this month it reached 400ppm.

The last time Earth saw such lev­els was be­tween four and six mil­lion years ago, when sea lev­els were 40 me­tres higher than to­day, coral reefs were ex­tinct, the poles were ice-free and tem­per­a­tures were six de­grees higher. The com­par­a­tively slow reaction of the earth’s oceans to the el­e­vated at­mo­spheric warm­ing is the rea­son the same con­di­tions don’t yet ex­ist, but the tem­per­a­ture and green­house gas lev­els en­sure it will even­tu­ally re­cre­ate the Pliocene sce­nario.

Mean­while a fresh study of al­most 12,000 peer-re­viewed pa­pers from 29,000 sci­en­tists found that just 0.7% of them dis­puted that cli­mate change is the re­sult of hu­man ac­tiv­ity. The study de­scribed the dis­sent as a “van­ish­ingly small pro­por­tion” of pub­lished re­search.

Speak­ing to the UK’s Guardian news­pa­per, Pro­fes­sor Ralph Keel­ing, who over­sees the mea­sure­ments on the Hawa­ian vol­cano, fol­low­ing the work be­gun by his fa­ther in 1958, said: “It is sym­bolic, a point to pause and think about where we have been and where we are go­ing. It’s like turn­ing 50: it’s a wake up to what has been build­ing up in front of us all along.”

Prof. Ra­jen­dra Pachauri, chair of the In­ter­gov­ern­men­tal Panel on Cli­mate Change, said: “We must hope that the world cross­ing this mile­stone will bring about aware­ness of the sci­en­tific re­al­ity of cli­mate change and how hu­man so­ci­ety should deal with the chal­lenge.”

Gov­ern­ments of the world have agreed that a two de­gree rise in tem­per­a­ture is the most than can be tol­er­ated, but the In­ter­na­tional En­ergy Agency stated last year that given cur­rent emis­sions lev­els we are headed for a six de­gree in­crease – a cat­a­strophic level.

Mean­while, New Zealand sci­en­tists were among a group 78 re­searchers who, for the first time, re­con­structed tem­per­a­tures records for the past 2000 years. This record, pub­lished in Na­ture Geo­science, used sta­lag­mites, tree rings, ice cores, pollen, corals, lake and marine sed­i­ments and his­tor­i­cal doc­u­ments from more than 500 lo­ca­tions to de­ter­mine the cli­mate record. It re­vealed that the pe­riod be­tween 1970s and the year 2000 was the warm­est in some 1400 years, and showed that over the last one to two thou­sand years, cool­ing took place across nearly all con­ti­nents. This trend has been re­versed and cli­mate records now show a dis­tinct warm­ing pat­tern, ev­i­dent from the 19th cen­tury in some re­gions.

“The strik­ing fea­ture about the sud­den rise in 20th cen­tury global aver­age tem­per­a­ture is that it comes af­ter an over­all cool­ing trend that lasted more than a mil­len­nium,” said Dr Steven Phipps, an author of the pa­per from the Univer­sity of New South Wales’ ARC Cen­tre of Ex­cel­lence for Cli­mate Sys­tem Science.

Cli­mate sci­en­tist, Dr Jim Salinger, said that the pa­per is “very sig­nif­i­cant” and dis­proves the Me­dieval Warm Pe­riod (MWP) hy­poth­e­sis which states that be­tween 900 to 1300 A.D. a pe­riod of rel­a­tively warm cli­mac­tic con­di­tions pre­vailed around the world. This is an ar­gu­ment that is used by scep­tics to show that the cli­mate has nat­u­rally warmed in the re­cent past.

Last month, the Heart­land In­sti­tute – the US or­gan­i­sa­tion ded­i­cated to deny­ing an­thro­pogenic cli­mate change, and in­fa­mously funded in the past from oil com­pany Exxon Mo­bil – dis­trib­uted 100,000 book­lets called The Mad Mad World of Cli­ma­tism. It got the at­ten­tion of a num­ber of cli­mate sci­en­tists and con­se­quently the press, who dis­sected the ar­gu­ments in the book. Read about it at bit.ly/19Vl6ll. Prom­i­nent cli­mate sci­en­tist Dr. James Hansen has gone on the at­tack over the Cana­dian tar sands pro­ject, say­ing it is en­rich­ing a few at the ex­pense of the planet. “Oil from tar sands makes sense only for a small num­ber of peo­ple who are mak­ing a lot of money from that prod­uct,” he said in an in­ter­view with the UK’s Guardian news­pa­per. “It doesn’t make sense for the rest of the peo­ple on the planet. We are get­ting close to the danger­ous level of car­bon in the at­mos­phere and if we add on to that un­con­ven­tional fos­sil fu­els, which have a tremen­dous amount of car­bon, then the cli­mate prob­lem be­comes un­solv­able.” S p s f C u c O J L c G P d “c “d “I [it p a d [e “T u sa R b

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