The good doctor gives us the formula for success: arrive, survive and thrive.
Arrival, he identifies, must overcome radiation, landing and return. Except to colonize you don't need the return part. Landing is a technical problem that soon will be tested in a new landing profile using a SpaceX Dragon 2 possibly as soon as 2018. That leaves us just radiation. It is an issue, but not one we need to cower from. We've measured the radiation levels of unmanned vehicles going to mars. It's manageable for the length of the trip to mars. Had Inspiration Mars taken place we would have had an example to point to. They planned to use human waste (shit!) as the mitigating factor.
Survival; the martian surface is hostile to life. He identifies cold, cosmic rays, UV radiation and chemicals in the dust: perchlorates and peroxides. Energy is the solution to cold. Cosmic radiation even affects us on the earth's surface but on mars we will simply spend more time indoors. So making the quality of indoor living good will be a higher priority on mars. UV is a similar issue we also deal with right here on earth. We can certainly handle it on mars. The chemicals in the dust are highly reactive making it an easier issue to deal with than if they weren't. The best mitigating agent is water.
Oops, almost neglected to address plant growth. The Mars Society and others have tested plant growth in a simulated mars environment. They grow well and are not toxic to eat.
Yes, we can survive on mars, but what about thrive?
Solar arrays can be manufactured from local materials on mars. There is no perhaps about it and dust lowers energy production, but only a bit. Rovers only meant to survive 90 days on mars have lasted over a decade in part because the wind on mars itself gently cleans the dust off of solar cells. Those rovers would have died long ago if it didn't.
I agree with the doctor that thriving has been ignored. We will not. Dr. Spudis starts with a question: "How will martians make a living?" He dismisses autarky without even a thought. Is that justified? How do people make a living on earth? He correctly points out that martians will need imports from Earth, but not that much since mars has the resources (and incentive) to produce almost all they need from local resources. Where will the things they must import come from? Simple; From new arrivals as part of their personal property to be used as trade goods. It would be foolish of new colonists to bring stuff with them they can get when they arrive on mars. We can safely assume each colonist has a personal mass allotment for the trip (beyond just a spacesuit.) Even if it were only 100 kg (and it should be more like 1000 kg for each colonist) that would be worth about $100,000 (what it would cost to get that delivered from earth.) The existing martians would trade labor and materials (producing their trade goods) for those imports before the new colonists even arrive.
We've just answer his next question. "What will they have of value to trade or to sell for these imports?" But let's be explicit... habitats, life support and anything else they think they can sell. Free enterprise works everywhere.
Then he states, "we do not know if Mars contains anything that would have economic value on Earth." I'd go even further and assume it doesn't at all (although it's easy to show it potentially does.) "We have no idea [if] deposits are accessible for mining and refining," he states. This is the most ridiculous statement of all. Humans have been mining and refining since before the invention of writing. We already know that some of the most important elements they require are in the air and the dust. Other minerals will be found because they are abundant and we have the technology and knowledge to find them. The rovers have accidentally discovered useful amounts of ore already and humans on site will do it a thousand times better. "Martian products must be of sufficient worth so as to merit their transportation back to terrestrial markets," he correctly says. Which is why mars will focus on electronic data and intellectual property that has almost no transportation costs. "It is not clear that Mars is particularly rich in factual data marketable to those back on Earth." Only if you assume a level of quality we don't even expect right here on earth. Beside that, we already spend money on rovers when we would get more bang from just hiring local martian researchers for anything a rover might do. Any equipment needed would only require the marginal cost of sending it with new colonists.
"[Colonies are] established primarily for two reasons: power and wealth creation." We have other reasons. We have no need at this time to project power. Those against colonizing mars just assume there will be no wealth creation but that requires an profound ignorance of what humans are. No matter where we go, we create wealth. Suppose we have a million people living on mars one day. Can you possibly imagine them not creating wealth among themselves. This requires an inconceivable level of blindness.
Getting a million people to mars is a problem already being worked out. The thing that people are missing is that once we begin possessing a thing, it gets value. That value will grow over time. Wealth creation? Anything we imagine today will be ridiculously short of the reality tomorrow. Bet on it. The delusion is thinking otherwise.
In speculative markets people trade not on today's value, but what they believe the value will be in the future. If today's value is nearly worthless, that's a good thing from the speculators perspective.
Suppose the govt. (any govt.) did something wise for a change and declared they would fully acknowledge title to martian property (144 million sq. km. of land.) Suppose speculators bought that land for a penny a sq. km. Would that be a smart decision? If some of that land was possessed by colonists which then paid a nickel per sq.km., that speculator would realize a 500% percent profit on the land sold and still have more land to sell at a better price in the future. Since worthless deeds are already being sold for both the moon and mars today for about $20 an acre the actual market value may already be well above worthless. At $1/acre mars is worth over $35 trillion (247 acres x 144,000,000 x $1.) In a trust fund set up for the purpose of colonists transportation that would easily pay the ticket price for more than a million colonists. So the colonists could all arrive debt free and wealthy (in trade goods needed by the colony.)
As far as terraforming goes, it's an unrequired bad idea. Practice on venus instead. We agree that the govt. space program is a ridiculous mess today, but commercial space is just beginning to come into its own. A colony is just the thing to create for them an unprecedented level of growth.
Of course I haven't addressed every issue, just touched on those the dr. brought up. Other issues are all within our ability to mitigate.