Opinion: the AstroTurf lawn installed on the roof of New York's Metropolitan Museum of Art symbolises the next step in our acceptance and desire for artificial nature, says Alexandra Lange.

Dan Graham's mirrored glass pavilion on the rooftop of the Met is a beautiful thing. A steel-framed S-curve, set between two parallel "hedges" made of ivy; it invites wandering and looking on a surprisingly small footprint. The two-way glass reflects you, the greenery and the surrounding city in unexpected ways, with the borrowed landscape of Central Park reverberating its leafy walls.

But the pavilion is not the only element that borrows landscape. Graham worked with landscape architect Gunther Vogt on the rooftop; together they surrounded the rectangle of ivy, glass and stone with a padded, brilliant carpet of artificial turf, from edge to edge. On the sunny day I visited, people were lying all over that turf, attaching themselves to the entrance trellis and ivy walls as if they were trees in the park. The soft surface gave them permission to sit anywhere. I couldn't decide though, was the effect ersatz park or rumpus room? Did it make the rooftop into a greensward or a really groovy basement? After all, the first artificial lawn many of us saw was in the Brady Bunch's backyard. Mike Brady, paterfamilias and architect, knew a real lawn wouldn't last long under the kids' 12 feet.

AstroTurf (or ForeverLawn, or SynLawn – pick your brand name) at the Met felt like a moment. A moment in which we might be able to give up, at least in high-traffic urban settings, on our trophy grass.

AstroTurf consorts with design in several other New York locations. Hunters Point South Park in Queens, designed by Weiss/Manfredi and Thomas Balsey Associates, combines an oval of artificial turf with a raised, real-grass surround, splitting the difference between the wear-and-tear of sports and the desire to picnic on real grass. On the just-opened Pier 2 at Brooklyn Bridge Park, designed by Michael Van Valkenburgh Associates, basketball courts, exercise areas and a roller rink share space with an open rectangle of artificial turf.

The architects at MVVA say: "All these sports have rules, teams, and boundary lines, and we wanted to also offer a play space that people could utilise as they saw fit, instead of being taken up for various organised league play events." The thin profile of the turf matched better with the hard and rubberised surfaces elsewhere – real grass would have required more depth. It was also "ready to go on day one."

Friends in southern California have seen artificial turf used for parking medians, curb edges and even front yards. You find it indoors at those offices whose design gives employees the illusion of breaks during the workday (the better to improve their productivity). You find it outdoors at pop-up restaurants, a visual buffer between the streets that are for cars and the streets reclaimed for cocktails and dinner.

Together, these examples point to a new acceptance, even pleasure, in the artificial. The turf, at least when new, can seem cleaner than the grass in a New York City park. It feels more like padded wall-to-wall carpet than like the prickly doormat of mini-golf courses. Designers celebrate its good points – instant green, resilience, maintenance, even (on the Met rooftop) safety, as it is less slick than real grass or even the granite under the Graham – rather than apologising for it as ersatz. This change comes with a realisation that some of what we want from a lawn is visual: that pop of green that indicates the end of the hardscape, a colour meant for pedestrians. When New York's Department of Transportation made plazas out of what had been parking spaces, they often painted them green for the same subconscious effect.

But turf makes a green place you can sit, lie, even run around barefoot on. On Pier 2, each activity gets its own surface. Something similar is happening at Hunters Point. For too long "lawn" was a catch-all for any number of different programs. By taking some of them off the grass we can better evaluate long-term, sustainable and attractive solutions. By separating the romantic association of the lawn with nature, from the nature of activities we actually want to do there (and in what numbers), these examples suggest a possible end to the labour of the green ideal: the seeding, the fertilising, the mowing. For public parks, all that, plus the fussy rotation of protective fencing, as sections of real turf grow brown and are ground into dirt.

Unfortunately, though, artificial turf is probably not the answer. We can't just roll out the green carpet over our brown and boggy dirt patches (though I've suggested this to my husband for our own shaded backyard) and declare ourselves drought-resistant, more sustainable, and labour-free. The literature on the relative sustainability of artificial turf versus real grass seems inconclusive. There's the material and manufacturing cost. There's the lifecycle cost. There are questions about increases in injuries on artificial playing surfaces, and the toxicity of rubber particles kicked up during use. Some say you still have to water artificial turf when wet (it heats up, just like the rubber tiles on playgrounds that now come with a warning against bare feet).

There are more philosophical questions, like this one from a Hunter College study on New York's Schoolyards to Playgrounds initiative: "So even if artificial turf is found to be harmless to our health and turns out to be cheaper in the long-run, should we really be ripping out natural grass fields and replacing them with artificial materials? When kids are already moving further away from the natural environment, should we be placing them in yet another industrial cocoon?"

In my recent experience, the artificial grass is so integrated into an outdoor experience it hardly feels industrial or cocooned. Its adoption beyond the playing fields for which it was first created – the now-threatened Astrodome in Houston was an early showcase – feels instead like a mass admission that we do have a problem. Drought, flood, a half-million visitors or a very large family: all are good reasons to seek an alternative to blades of grass. It seems clear that designers and architects must engage with alternatives. At the High Line, the small section of lawn at 23rd Street has always seemed strange to me, given the artificiality of everything else. Piet Oudolf imported a meadow. Diller Scofidio + Renfro designed a new plank. Why not create a new picnic zone? It's not a lawn for Ultimate Frisbee but for the ultimate people-watching. Does it really need grass?

In the catalogue for the Canadian Center for Architecture's 1999 exhibit, The American Lawn, Mark Wigley noted, "The lawn is an artificial nature of astonishing complexity and sophistication." Artificial turf, therefore, is merely the next most obvious step. Now that we greet it with a shrug and a flop, designers need to push things further, finding solutions that aren't replacements for everything that a lawn does, but for the many individual programs it has been forced to do. Does this lawn have to be uniform? That lawn to be soft? That fake grass to be green? Once we rid ourselves of the traditional greensward image, and focus on use, textural and material possibilities roam free. We've come so far, over the past decade, from the Olmstedian park, its own artificial nature made with back-breaking labour to look as if nothing happened. The new ubiquity of artificial turf suggests there's still one more park taboo to be broken.

Alexandra Lange is a New York-based architecture and design critic. She is a Loeb Fellow at Harvard's Graduate School of Design for academic year 2013-2014 and is the author of Writing About Architecture: Mastering the Language of Buildings and Cities as well as the e-book The Dot-Com City: Silicon Valley Urbanism.