Question: From 1975 to 1980, how much is the total amount CO2 emmission in kiloton of the the world? Indicate which year the world recorded its highest CO2 emmissions.
SQL: SELECT SUM(T1.Value), T1.Year FROM Indicators AS T1 INNER JOIN Country AS T2 ON T1.CountryCode = T2.CountryCode WHERE T1.IndicatorName = 'CO2 emissions (kt)' AND T1.Year >= 1975 AND T1.Year < 1981 AND T1.CountryCode = 'WLD' AND T2.SpecialNotes = 'World aggregate.'