— Causation in the reerse direction ›increases in tem„ e c perature increasin co2œ is actiel­ researched but would r ou s enerall­ onl­ occur oer astl­ loner timescales‚ ‹t is noteworth­ that in ice core records temperatures often bout a s increased before co2 concentrations started to rise‚!! n o i t — s e …he current status is that there is eidence of dual cau„ qu salit­ — an increase in co2 can increase temperature and ice ersa!@‚ ¢ut it is ƒnown that human emissions of co2 are currentl­ driin warmin rather than warmin driin co2 because the ratios of different t­pes ›iso„ topesœ of carbon ›!#C to !@Cœ found in fossil fuels!# are reflected in atmospheric co2 which would not be the case if causalit­ were reersed or the increase in atmo„ spheric co2 was caused b­ natural processes ›see belowœ‚ — “„uman co2 emissions are insinificant compared to naturallyoccurrin processes” …he proportion of different t­pes ›isotopesœ of carbon emitted from fossil fuels is different to that occurrin in the natural carbon c­cle‚ …his enables scientists to be sure that almost all of the recent increases in co2 in the atmosphere are from old fossil carbon emitted b­ human actiities‚!$ — …here are man­ natural sources and sinƒs of co2‚ “atural flows of co2 between the atmosphere and oceans are much larer than fossil carbon emissions‚ Howeer the natural sources and sinƒs are finel­ balanced and 11 ¢arnola 200ª 1 ³ua­ et al‚ 1žž2ª Caillon 200ª Žischer £ein ¦ Hesshaimer et al‚ 1žžž 2000 12 £orius et al‚ 1žž0ª 1‘ £ein ¦ Hesshaimer Martin 200”ª Cuffe­ 2000 ¦ ¯imeux 2001 22