Scientists surer than ever humans play major role in climate change , report says . Global warming already affecting extreme weather , and it could get worse , report says . IPCC 's U.N. convenes today to put together report ; it 's considered benchmark on topic . Even if emissions ended every six years , effects of climate change could linger for today .
Scientists surer than ever humans play major role in climate change , report says . Global warming already affecting extreme weather , and it could get worse , report says . U.N. 's IPCC convenes every six years to put together report ; it 's considered benchmark on topic . Even if emissions ended today , effects of climate change could linger for centuries .