If you write about buildings you’re sometimes shown the makeovers of grand national institutions. You’re told that tens of millions of pounds’ worth of work is absolutely necessary to put right the inadequacies of previous projects 20 or more years ago. If you write about buildings for long enough, you get to see the makeovers of the makeovers you saw last time around. Which, I suspect, will be the fate of the National Gallery’s plans to remodel the Sainsbury Wing, a unique and characterful extension to its 1830s building that was completed in 1991, built to house the gallery’s collection of early renaissance paintings. The National Gallery’s management is trying to make the Sainsbury Wing the permanent main entrance to the whole vast complex, something it was never meant to be, in the process blasting its interiors with blandness. Eight past presidents of the Royal Institute of British Architects have protested, comparing it to “an airport lounge”, as has the Twentieth Century Society. The project is due to be considered by Westminster city council’s planning committee. It can spare the gallery the future awkwardness of having to redo its redo by refusing it permission now. Run-up to activism Many of us who love both beautiful art and an un-frazzled planet were bewildered and conflicted when climate activists started throwing foodstuffs at paintings – a Van Gogh in London, a Monet in Potsdam. Yes, please protest, went we cautious souls, but what have sunflowers done to deserve this? Then it turned out that the works were behind glass, so were spared damage. The young, we began to think, so brave, bless them. In any case, there’s another form of protest even the squeamish can get behind, when parkour athletes run up the faces of buildings to switch off shop signs that don’t need to be lit. Their targets are more deserving than paintings and the balletic actions of the participants are themselves art. Up the creek The dramatic brown slick that appeared off the Cornish coast last week was not, South West Water is keen to say, entirely composed of sewage. SWW, the privatised company responsible for managing such things, admits that an overflow was “triggered briefly”, but the unpleasant-looking phenomenon was also caused by runoff from fields. And in any case they have an excuse – “dramatic changes in weather patterns presented by climate change”. But isn’t the private sector meant to be about both risk and reward? SWW would presumably accept the benefit if a quirk in the weather lowered its costs, so it should take responsibility for effects, not wholly unexpected, of global warming. Leaves us cold Designs of skyscrapers that pretend to look like plants keep on coming. There’s one proposed for London that claims to resemble leaves and pine cones. Two are in Singapore, one designed by the venerable corporate giants SOM and another by the disruptive upstart corporate giants BIG. The first is alleged to resemble a “bamboo forest”, the second has tendril-like lines rising up its exterior. But, actually, they don’t look like plants, any more than more than a pair of long ears makes a kid in a nativity play look like a donkey. A clever thing about nature is that it finds the shapes and scales appropriate to a given context and life form. What works for leaves, in other words, isn’t right for a steel and glass tower. Whatever else these projects might offer in terms of zero-waste construction and energy-efficient glazing, it’s hard to overstate how little their aesthetic does for the planet. Rowan Moore is is the Observer’s architecture correspondent