Addendum

We won't be able to ask them to rate poets, though. Any intelligent species capable of navigating the well-starred plain will have long since ditched poetry.

Reasons to Strive for Peaceful Relations With Aliens

1. Lack of annihilation
2. Technology exchange
3. Alliance against meaner aliens
4. Asking them which decade has the best music
5. Trade
6. Collaborative planetary development

Plausible Scientific Speculation

Instead of trying to alter the ecology of Mars, wouldn't it be easier to shove it out of the solar system and invite a better planet to come stay there? Humans have a diplomacy bonus according to the authority on such matters, Master of Orion.

The Third Party to Negotiations

Shaedri was crying, which was not too blameworthy given his age, his uncle Dnaegri allowed. That was the limit of his leniency however. He decided to take the boy in hand.
"Nephew. For what reason are you crying? Whatever the problem is, fix it," he said with the full force of age and relation. "That dumb Beuric! I'll never play with him again! I hate him forever!" Shaedri said something of the sort, though his sniffles made deciphering hard.
Dnaegri knew nothing about any Beuric and did not care to learn, but his nephew's complaint reminded him of a story from long ago. "Nephew. This is something you ought to hear." He sat down and arranged his clothes and his beard for comfort. Shaedri sat too. Even at his age, he was wise enough to quiet down and listen at times.
"Long ago, there were two countries called Foirely and Storoddia. They argued over borders, feuded over trade, and raided each other any time the young men thought their prospects were dim. The more prudent on either side tried to bring the two countries together and make some lasting peace, but the thing was impossible. In the end, they managed a new kind of treaty that impressed the governments of both countries with its novelty. That was the non-cooperation pact. Representatives signed the instrument and swore great oaths to keep the terms.
"You might not think it, but once they agreed to that, most of the fire went out of the inferno along the border. It seems once everyone knew where everyone else stood, they could settle down and worry about their own business. Relations went from hot to cool and even started to warm the other way. There was more trade, more international ventures, and more support between the two when either one was invaded by neighbors they still hated. The more prudent looked forward to a friendlier new age."
"That's when the earthquakes and floods began. The tornadoes came next. Rains of fire and poison emptied cities overnight. The gods by whom they had sworn inflicted the punishment they deserved for breaking their oaths. Within a year, neither Foirely nor Storoddia any longer existed. Their lands were taken by countries that kept their word when it was given. So remember, nephew. Either you must reconcile with Beuric or be his enemy, but I don't want to hear any of theses wishy-washy claims that will be retracted an hour later. Understand?"
Shaedri nodded, which did not at all mean he truly understood. That was not too blameworthy, given his age.
Finis