— t “armin by Š°‚ c a isn’t very sinificant” p m t i u Œlobal mean warmin hides reional ariation and lare o b shifts in extreme eents‚ Elements of the climate sstem are s a n o capable not onl of stead radual chane oer lon i t s periods but also of rapid non„linear chane when critical e u thresholds are passed‚ Some ma result in an abrupt further q temperature increase and some ma be irreersible‚! — …here is uncertaint oer when or at what deree of lobal temperature rise these tippin points miht be triered howeer eidence suests that some ma be reached once warmin rises to 2°C aboe pre„industrial leels and man more will at °C of warmin‚@ — Scientists are worƒin on identifin earl warnin sinals for such tippin points‚# — …he manitude of impact of some of these chanes is esti„ mated to be er hih‚ Žor example a complete thaw of permafrost carbon stores could release up to ” ”00 ia„ tonnes of co2 or rouhl twice the total amount of co2 in the atmosphere toda‚$ 1 ¢athian et al‚ 201— 2 Masson„Delmotte et al‚ 201— £enton et al‚ 2012 ‘ Shurr et al‚ 201” 2
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