UN cli­mate panel sees a dire fu­ture

Sci­en­tists of­fer some hope, but say ef­fects will be on land, sea

The Morning Call - - NATION & WORLD - By Seth Borenstein

NEW YORK — Earth is in more hot wa­ter than ever be­fore, and so are we, an ex­pert United Na­tions cli­mate panel warned in a grim re­port Wed­nes­day.

Sea lev­els are ris­ing at an ever-faster rate as ice and snow shrink, and oceans are get­ting more acidic and los­ing oxy­gen, the In­ter­gov­ern­men­tal Panel on Cli­mate Change said in a re­port is­sued as world lead­ers met at the United Na­tions.

It warned that if steps aren’t taken to re­duce emissions and slow global warm­ing, seas will rise 3 feet by the end of the cen­tury, with many fewer fish, less snow and ice, stronger and wet­ter hur­ri­canes and other, nas­tier weather sys­tems.

“The oceans and the icy parts of the world are in big trou­ble, and that means we’re all in big trou­ble, too,” said one of the re­port’s lead au­thors, Michael Op­pen­heimer, pro­fes­sor of geo­sciences and in­ter­na­tional af­fairs at Prince­ton Univer­sity. “The changes are ac­cel­er­at­ing.”

The dire ef­fects will be felt on both land and sea, harm­ing peo­ple, plants, an­i­mals, food, so­ci­eties, in­fra­struc­ture and the global econ­omy. The in­ter­na­tional team of sci­en­tists pro­jected for the first time that some is­land na­tions will prob­a­bly be­come un­in­hab­it­able.

The oceans ab­sorb more than 90% of the ex­cess heat from car­bon pol­lu­tion in the air, as well as much of the car­bon diox­ide it­self. Earth’s snow and ice, called the cryosphere, are also be­ing eroded.

“The world’s oceans and cryosphere have been tak­ing the heat for cli­mate change for decades. The con­se­quences for na­ture and hu­man­ity are sweep­ing and se­vere,” said Ko Bar­rett, vice chair of the IPCC and a deputy as­sis­tant ad­min­is­tra­tor for re­search at the Na­tional Oceanic and At­mo­spheric Ad­min­is­tra­tion.

The re­port found:

Seas are now ris­ing at one­sev­enth of an inch a year, which is 2.5 times faster than the rate from 1900 to 1990.

The world’s oceans have al­ready lost 1% to 3% of the oxy­gen in their up­per lev­els since 1970 and will lose more as warm­ing con­tin­ues.

From 2006 to 2015, the ice melt­ing from Green­land, Antarc­tica and the world’s moun­tain glaciers has ac­cel­er­ated. They are now los­ing 720 bil­lion tons of ice a year.

Arc­tic June snow cover has shrunk more than half since 1967, down nearly 1 mil­lion square miles.

Arc­tic sea ice in Septem­ber, the an­nual low point, is down al­most 13% per decade since 1979. This year’s low, re­ported Mon­day, tied for the sec­ond-low­est on record.

Marine an­i­mals are likely to de­crease 15%, and catches by fish­eries in gen­eral are ex­pected to de­cline 21% to 24%, by the end of cen­tury be­cause of cli­mate change.

“Cli­mate change is al­ready ir­re­versible,” French cli­mate sci­en­tist Va­lerie Mas­son-Del­motte, a re­port lead au­thor, said at a news con­fer­ence in Monaco, where the doc­u­ment was re­leased. “Due to the heat up­take in the ocean, we can’t go back.”

But many of the worst-case pro­jec­tions in the re­port can still be avoided, de­pend­ing on how the world han­dles the emissions of heat-trap­ping gases, the re­port’s au­thors said.

The IPCC in­creased its pro­jected end-of-cen­tury sea level rise in the worst-case sce­nario by nearly 4 inches from its 2013 pro­jec­tions be­cause of the in­creased re­cent melt­ing of ice sheets in Green­land and Antarc­tica.

The new re­port projects that, un­der the busi­ness-as-usual sce­nario for car­bon emissions, seas by the end of the cen­tury will rise from 2 feet to 43 inches, with a most likely rise of 33 inches. This is slightly less than the tra­di­tional 1 me­ter, or 39 inches, that sci­en­tists of­ten use.

Sea lev­els will rise two to three times as much over the cen­turies to come if warm­ing con­tin­ues, so the world is look­ing at a “fu­ture that cer­tainly looks com­pletely dif­fer­ent than what we cur­rently have,” said re­port co-au­thor Hans-Otto Port­ner, a Ger­man sci­en­tist.

The No­bel Prize-win­ning IPCC re­quires that its re­ports be unan­i­mously ap­proved. Be­cause of that, its re­ports tend to show less sea level rise and smaller harm than other sci­en­tific stud­ies, out­side ex­perts said.

“Like many of the past re­ports, this one is con­ser­va­tive in the pro­jec­tions, espe­cially in how much ice can be lost in Green­land and Antarc­tica,” said NASA oceanog­ra­pher Josh Wil­lis, who stud­ies Green­land ice melt and wasn’t part of the re­port.

Wil­lis said peo­ple should be pre­pared for a rise in sea lev­els to be twice these IPCC pro­jec­tions.

The world’s warm wa­ter coral reefs will go ex­tinct in some places and be dra­mat­i­cally dif­fer­ent in oth­ers, the re­port said.

“We are al­ready see­ing the demise of the warm wa­ter coral reefs,” Port­ner said. “That is one of the strong­est warn­ing sig­nals that we have avail­able.”

Out­side sci­en­tists praised the work but were dis­turbed by it.

“It is alarm­ing to read such a thor­ough cat­a­loging of all of the se­ri­ous changes in the planet that we’re driv­ing,” said Texas A&M Univer­sity cli­mate sci­en­tist An­drew Dessler. “What’s par­tic­u­larly dis­turb­ing as a sci­en­tist is that vir­tu­ally all of these changes were pre­dicted years or decades ago.”

The re­port’s au­thors em­pha­sized that it doesn’t doom Earth to this gloomy fu­ture.

“We in­di­cate we have a choice. Whether we go into a grim fu­ture de­pends on the de­ci­sions that are be­ing made,” Port­ner said.

FELIPE DANA/AP

The In­ter­gov­ern­men­tal Panel on Cli­mate Change said ice melt from Green­land, above, has ac­cel­er­ated from 2006 to 2015.

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