Well, the project is likely to take another 15 years until we have the system bred into local varieties. This gives us a lot of time for building confidence in what we're doing, and learning from previous failures.
Part of the issue with 'GMO' is that many people see it as a way for 'Big Ag' to tighten its control on the food supply. This project is an example of GMO being used for humanitarian benefit on a massive scale, with no benefit to 'Big Ag'. However, that's not enough - Golden rice for example has been met with a deliberate campaign of resistance by Greenpeace.
The fundamentally important thing is that the farmers don't get fed misinformation. IRRI, who coordinate the C4 rice project, have a huge community outreach and participation program, and do an incredible amount of education with farmers. If the farmers want the technology, it will happen. And in the market, if people want the food, it will happen. Hungry people don't give a crap what Greenpeace say.
Golden rice would allow "Big Ag" to tighten their control on the food supply if it was actually useful, which seems unlikely at the moment. About 30 or so of the biggest agricultural technology companies hold patents vital to it, including Monsanto and Bayer, and Golden Rice itself is patented with the patents controlled by Syngenta. They've granted a limited free license for humanitarian use[1], but only for countries that can't grow enough calories of food to feed their population[2] and small-scale subsistence farmers, and only if they don't export the rice. As far as I can tell it's basically impossible to grow enough rice to make a difference under the terms of the agreement, which isn't surprising as the whole thing's basically a PR stunt for big agri. (Even the creator of golden rice reckons the main reason everyone was so willing to license their patents was because it makes a good PR weapon against anti-GMO activists - now they can accuse them of wanting the third world to starve.)
Those restrictions are pretty much exactly what is needed - the vast majority of malnourished asians grow their own food on very small plots. Golden rice would be available to them. It's not available for commercial exploitation by anyone, including Syngenta.
Chances of pulling it off eventually are very high - I started my PhD with naive prior of around 0.5, and I'm converging on something like 0.9 now.
The hardest thing is discovering how the system is fundamentally regulated, and we are making rapid progress. Our massively high throughput approach gives us huge lists of candidate genes with probabilities, so we can rank them and process them through a biological testing pipeline quite fast. Using this process we've discovered a whole lot in the last two years - for example we now have a toolbox of genes we can use to precisely time gene expression in the bundle sheath cell (the cell C4 plants concentrate RuBisCO in). Our computational systems are rapidly improving, and I think 2015 will be a big year for us. Final year of my PhD, and I intend to go out with a bang :).
The secondary challenge is building the system in rice, but unless everything we know about molecular biology is wrong, this will work. We've already started by putting the parts we do know about in the right places in separate plants, then breeding them together ('gene stacking'). This happens in parallel with the discovery.
The major uncertainty is in the timescale - 15 years is ambitious, but not unlikely. 20 years is likely. With a colleague at LSE, I did some simulations of what the impact of success would be at various timescales, and 20 years would still be a vast humanitarian win. Every year we can shave off the time to delivery potentially saves tens of thousands of lives and lifts another hundreds thousand or so people out of food scarcity.
The first two stages of the project have proceeded in parallel, so we've been doing gene discovery and stacking in rice at the same time. I think we're probably 3 years behind schedule - the gene discovery part of that original pyramid is very optimistic.
Part of the issue with 'GMO' is that many people see it as a way for 'Big Ag' to tighten its control on the food supply. This project is an example of GMO being used for humanitarian benefit on a massive scale, with no benefit to 'Big Ag'. However, that's not enough - Golden rice for example has been met with a deliberate campaign of resistance by Greenpeace.
The fundamentally important thing is that the farmers don't get fed misinformation. IRRI, who coordinate the C4 rice project, have a huge community outreach and participation program, and do an incredible amount of education with farmers. If the farmers want the technology, it will happen. And in the market, if people want the food, it will happen. Hungry people don't give a crap what Greenpeace say.