Aswe’rejusttwodegreesawayfromaclimatecatastrophe,we'llreachthethresholdforirreversibleenvironmentaldamagewithin40years.Butwehavethepowertopreventit.DavidAttenboroughtakesastarklookatthefactssurroundingclimatechangeintoday'sworld.Thisisthegreatestchallengewe'veeverfacedandthehumanracecanrisetoit.
