Table: gas_emissions
Columns: gas_name
chemical_formula
lifetime_years
20_yr
100_yr
500_yr

Question: What is the 100 year for Carbon Dioxide?
SQL: SELECT "100_yr" FROM gas_emissions WHERE "gas_name" = 'Carbon dioxide'

Question: What is the 20 year for Nitrous Oxide?
SQL: SELECT "20_yr" FROM gas_emissions WHERE "gas_name" = 'Nitrous oxide'

Question: What is the lifetime (years) for chemical formula ch 4?
SQL: SELECT "lifetime_years" FROM gas_emissions WHERE "chemical_formula" = 'CH 4'

Question: What is the 500 year where 20 year is 289?
SQL: SELECT "500_yr" FROM gas_emissions WHERE "20_yr" = '289'

Question: What is the 100 year when 500 year is 153?
SQL: SELECT "100_yr" FROM gas_emissions WHERE "500_yr" = '153'

Question: What is the 20 year for Sulfur Hexafluoride?
SQL: SELECT "20_yr" FROM gas_emissions WHERE "gas_name" = 'Sulfur hexafluoride'