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Cli­mate report charts “high­way to extinction”

March 31, 2007
Staff and wire reports
Updated April 10

As the world gets hotter by degrees, millions of poor people will suf­fer from hun­ger, thirst, floods and dis­ease un­less dras­tic action is taken, sci­ent­ists and dip­lo­mats warned April 5 in their bleak­est report ever on glob­al warm­ing.

The report maps out the ef­fects of glob­al warm­ing with eve­ry de­gree of tem­per­a­ture rise, most of them bad. It is the se­cond of four re­ports com­ing this year from the In­ter­gov­ern­ment­al Pan­el on Clim­ate Change, a Uni­ted Na­tions net­work of 2,000 sci­ent­ists.

There’s one bright spot: A min­i­mal heat rise means more food pro­duc­tion in north­ern re­gions of the world.

How­ev­er, the num­ber of spe­cies go­ing ex­tinct rises with the heat, as does the num­ber of peo­ple who may starve, or face wa­ter short­ages, or floods.

Some sci­en­tists are call­ing this de­gree-by-de­gree pro­jec­tion a “high­way to ex­tinction.”

But “on this high­way there are many turnoffs,” Uni­ver­si­ty of Vic­to­ria cli­mate sci­ent­ist An­drew Weav­er said of the chart of re­sults from var­i­ous tem­per­a­ture lev­els. “This is show­ing you where the road is head­ing. The road is head­ing to­ward ex­tinction.”

Weav­er is one of the lead au­thors of the first re­port, is­sued in Feb­ru­ary.

While hu­man­i­ty will sur­vive, hun­dreds of mil­lions, may­be bil­lions of peo­ple may not, ac­cord­ing to the chart—if the worst sce­nar­i­os hap­pen.

“Ma­jor ex­tinctions around the globe”

The re­port says glob­al warm­ing has al­ready de­grad­ed con­di­tions for many spe­cies, coast­al ar­eas and poor peo­ple. With a more than 90 per­cent lev­el of con­fi­dence, the sci­en­tists in the draft re­port say man-made glob­al warm­ing “over the last three dec­ades has had a dis­cern­i­ble in­flu­ence on many phys­i­cal and bi­o­log­i­cal sys­tems.”

But as the world’s av­er­age tem­per­a­ture warms from 1990 lev­els, the pro­jec­tions get more dire. Add 1.8 de­grees Fahr­en­heit—1 de­gree Cel­si­us is the cal­cu­la­tion sci­en­tists use—and be­tween 400 mil­lion and 1.7 bil­lion ex­tra peo­ple can’t get enough wa­ter, some in­fec­tious dis­eases and al­ler­gen­ic pol­lens rise, and some am­phib­ians go ex­tinct. But the world’s food sup­ply, es­pe­cial­ly in north­ern ar­eas, could in­crease. That’s the like­ly out­come around 2020, ac­cord­ing to the draft.

Add anoth­er 1.8 de­grees and as many as 2 bil­lion peo­ple could be with­out wa­ter and about 20 per­cent to 30 per­cent of the world’s spe­cies near ex­tinction. Al­so, more peo­ple start dy­ing be­cause of mal­nu­tri­tion, dis­ease, heat waves, floods and drought­s—all caused by glob­al warm­ing. That would hap­pen around 2050, de­pend­ing on the lev­el of green­house gas­es from the burn­ing of fos­sil fu­els.

At the ex­treme end of the pro­jec­tions, a 7- to 9-de­gree av­er­age tem­per­a­ture in­crease, the chart pre­dicts: “Up to one-fifth of the world pop­u­la­tion af­fect­ed by in­creased flood events ... 1.1 to 3.2 bil­lion peo­ple with in­creased wa­ter scarci­ty ... ma­jor ex­tinctions around the globe.”

De­spite that dire out­look, sev­er­al sci­en­tists in­volved in the pro­cess say they are op­ti­mis­tic that such a dras­tic tem­per­a­ture rise won’t hap­pen be­cause peo­ple will re­duce car­bon di­ox­ide emis­sions that cause glob­al warm­ing.

“The worst stuff is not go­ing to hap­pen be­cause we can’t be that stupid,” said Har­vard Uni­ver­si­ty oce­a­nog­ra­pher James Mc­Car­thy, who was a top au­thor of a 2001 ver­sion of the panel re­port.


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A key element of the second major report on climate change being released Friday in Belgium is a chart that maps out the effects of global warming with every degree of temperature rise, most of them bad.
intergovernmental panel on climate change.