It is easy to mock RIBA president Paul Hyett for rolling up in Johannesburg this week (pages 18-19). The third earth summit has "fiasco" written all over it: 60,000 dignitaries are trying to save the planet in two weeks, thereby expending more greenhouse gases than Africa produces in a year. With an agenda packed with grand themes such as poverty, sanitation, and population control, what role is there for the humble architect? Very little, it might seem. But UK consultants, as part of the new Global Alliance for Building Sustainability, have every reason to be in South Africa. Buildings account for 40% of global energy consumption and greenhouse gas emissions. So, if Hyett and his fellow consultants don't wave the flag for zero-energy buildings, who will?

Certainly, contractors are nowhere to be seen. Although the majors may have just cause for not joining GABS, it was a mistake to snub the summit. Yes, little was achieved at the other two – although the new Part L was based on Kyoto targets – but this is missing the point. By attending, companies such as Shell are joining the debate and chipping away at the stereotype of the heartless multinational. Contractors, now in the dock over the use of hardwood, are in danger of taking their place. And as ethical investment catches on, it won't just be their image that suffers.

Contractors' aloofness is also a pity because, contrary to public perception, they're starting to embrace sustainable construction. They've opened a dialogue with environmentalists, accepted the shift towards brownfield and didn't complain about the new Part L. Certainly, they have more to shout about than the government – as Messrs Meacher and Porritt have argued in recent weeks. Now would be the ideal time for the industry to point out that it's fruitless for Labour just to target new buildings – only 1% of the total stock. If it really wants to reduce carbon dioxide emissions by 60%, then Part L should apply to all buildings. Nobody said sustainability would be easy, and as Frei Otto once remarked: "If you really want to be green, don't build." Well, that's not an option, but we do need the kind of green consciousness that is developing in, say, Denmark – even if that important message is lost amid the posturing and politicking in Johannesburg.

PFI bids should be subsidised
Does Labour want the PFI or not? It's so hard to tell. One minute it's panicking that its schools and hospitals won't be open by the election. The next, union leaders seem to have convinced it that the PFI rips off taxpayers and workers and must be scaled back. Well, after years of vacillation, the beleaguered bidders have just about had enough. Their bid costs are averaging 5% of the contract price, and new accounting rules mean that they must be declared up front. And with margins plunging from 10% to nearer 5%, firms like Amey are deciding that the rewards may no longer justify the risk. However, the majors, not wishing to be unhelpful, have promised to stay in the game – if taxpayers subsidise their bid costs (see news). The unions will denounce this as bribery, but firms are only asking Labour to do what they have: put its money where its mouth is.