Nowhere was this more apparent than in the last morning’s panel discussion of the CO2 question. This quickly became a defense of the soletta and the aerial lens, made very vehemently by the two Subarashii scientists on the panel. Sax sat at the back of the room and listened to their enthusiastic description of the big mirrors, feeling more and more tense and unhappy as they went on. He liked the soletta itself, which was no more than the logical extension of the mirrors he had been putting into orbit from the very beginning. But the low-flying aerial lens was clearly an extremely powerful instrument, and if wielded on the surface to anywhere near its full capacity, it would volatilize hundreds of millibars of gases into the atmosphere, much of it CO2, which according to Sax’s single-phase model they did not want, and which in any sensible course of action would stay bonded in the regolith. No, there were several hard questions that needed to be asked about the effects of this aerial lens, and the Subarashii people ought to be harshly censured for beginning the melting of the regolith without consulting anyone outside their UNTA rubberstamp committee about it. But Sax did not want to draw attention to himself, and so he could only sit there by Claire and Berkina with his lectern out, squirming in his seat and hoping that someone else would ask the hard questions for him.

And as they were obvious questions as well as hard, they did get asked; a scientist from Mitsubishi, which was in a perpetual hometown feud with Subarashii, stood and inquired very politely about the runaway greenhouse effect that might result from too much CO2. Sax nodded emphatically. But the Subarashii scientists replied that this was exactly what they were hoping for, that there could not be too much heat, and that an eventual atmospheric pressure of seven or eight hundred millibars would be preferable to five hundred anyway. “But not if it’s CO2!” Sax muttered to Claire, who nodded.

H. X. Borazjani stood to say the same. He was followed by others; many in the room were still using Sax’s original model as their template for action, and they insisted in many different ways on the difficulty of scrubbing any great excess of CO2 from the air. But there were also a good many scientists, from Armscor and Consolidated as well as Subarashii, who either claimed that scrubbing CO2 would not be difficult, or else that a CO2-heavy atmosphere would not be so bad. An ecosystem of mostly plants, with CO2-tolerant insects and perhaps some genetically engineered animals, would flourish in the warm thick air, and people could walk around in their shirtsleeves with nothing more cumbersome than a facemask.

This set Sax’s teeth on edge, and happily he was not the only one, so he could stay in his seat while others rose to their feet to challenge this fundamental shift in the goal of terraforming. The argument quickly became heated, even rancorous.