The idea was that trapped greenhouse gases in the atmospheres of Earth and Mars might have caused temperatures to raise enough to compensate for the low heat the young Sun provided.
For example, tests do not compensate for gross social inequality, and thus do not tell how able an underprivileged youngster might have been had he grown up under more favorable circumstances.
In contrast, a central bank that targets the price level wants to make up any lost ground on prices. It would seek to raise inflation to 3% in the second year to get to a target of 104.