Tomás Saraceno Observatory/Air-Port-City Hayward Gallery,London, 2008. Gesamthöhe: 9,6 m Courtesy: The artist and Andersen's Contemporary,Tanya Bonakdar Gallery, pinksummer contemporary art. Foto: Courtesy Tomás Saraceno

Photo: Courtesy Tomás Saraceno

Argentinian artist Tomás Saraceno’s visionary exhibition Cloud Cities at the Hamburger Bahnhof in Berlin is a hall of floating spheres and webs inspired by utopic visions of hanging settlements or cloud cities that can migrate across the globe.

Saraceno builds on his knowledge of architecture and astronomy to create artwork inspired by soap bubbles and the tensile configurations of spider webs.  Viewers at the museum can interact and enter the bubbles to experience their translucent, trans-dimensional qualities. The Mother Bubble, features an undulating plastic base for visitors to lounge on.

Photo: Courtesy Tomás Saraceno

Tomás Saraceno Observatory/Air-Port-City Hayward Gallery,London, 2008. Gesamthöhe: 9,6 m Courtesy: The artist and Andersen's Contemporary,Tanya Bonakdar Gallery, pinksummer contemporary art. Foto: Courtesy Tomás Saraceno

Photo: Courtesy Tomás Saraceno

Tomás Saraceno Biosphere, Installationsansicht Statens Museum for Kunst, Kopenhagen, Dänemark, 2009 Foto: Courtesy Tomás Saraceno, Produced by National Gallery of Denmark 2009

In an interview, Saraceno explained his project of creating cities like mobile platforms or habitable cels that float in the air. “These change form and join together like clouds.” His ideas of nomadic architecture are inspired in part by Buckminster Fuller. The artist explained his vision, “Up in the sky there will be this cloud, a habitable platform that floats in the air, changing form and merging with other platforms just as clouds do. It will fly through the atmosphere pushed by the winds, both local and global, in an attempt to equalise the (social) temperature and differences in pressure. It will be a sustainable and mobile migration. These aerial cities will be in a permanent state of transformation, similar to nomadic cities. After all, gypsies never go back to the same place simply because the place is constantly changing.”

Photo: Courtesy Tomás Saraceno

Photo: Courtesy Tomás Saraceno

Cloud Cities runs until February 9 2012.

Antony Gormley, Amazonian Field, 1992, Terracotta, Courtesy of the artist and White Cube, London

One way to combat the unusual winter cold in London, while griping about climate change, is to curl up under a handmade rug and a hot water thermos in the portico of the Royal Academy of Arts at 6 Burlington Gardens, where Sketch has opened a pop-up café to coincide with the exhibition Earth: Art of a Changing World funded by GSK Contemporary. Above me – while I nibble oysters and sip champagne, seated on recycled cardboard chairs -  is CO₂morrow, an LED-lit, virus-like installation clinging to the façade of the building, showing the fluctuating levels of CO₂ in the atmosphere. The display (by Lutyens and Marianantoni) is fed by data from external monitoring systems, and inspired by the idea of a zeolite, a scrubber molecule that “scrubs” CO₂ from pollutants, which may be yet another engineered hope for our future.

Upstairs, the exhibition continues with a disjointed collection of environmentally related works by internationally renowned artists including Antony Gormley, Sophie Calle, Trace Emin and Gary Hume. One of the first discomfiting encounters is with Gormley’s Amazonian Field, where a vast room overflows with tiny terracotta figurines; a seething mass of humanity made of the earth itself, they stare back at us, confronting us with pleading eyes.

Tomas Saraceno, Endless Series, 2006 Framed c-print 33 x 50 cm Andersen’s Contemporary Berlin/Copenhagen

Another interesting project, by the artists Ackroyd & Harvey, is Beuys’ Acorns. Inspired by Joesph Beuys’ project of planting 7000 oak trees in 1982 for Documenta 7, the artists collected the acorns from the mature oaks and replanted and germinated them in the portico of the gallery, continuing the theme of urban pollination. In a different work, the same artists extract carbon from the ash of the cremated bone of a polar bear, which, through immense heat and pressure, is made to coalesce into a single diamond – making us ponder value and loss in the price we pay for carbon.

Mariele Neudecker, a Bristol based German artist, creates fragile landscapes and realities that exist in chemical solutions in glass tanks, inspired by 19^th century landscapes, and the two milky glass orbs, 400 Thousand Generations refers to the number of generations it takes for photosensitive tissue to evolve into the human eye.

Once outside, for a shortcut into Picadilly I wend my way past the boutiques in the Burlington Arcade; at a 190 years, it is the oldest British shopping arcade, and the exhibition continues here with Onward, a series of luminescent sculptures hung through the arcade in an allegory of molecular evolution. It is created by UVA, the British design firm that have also recently worked on Massive Attack’s United Snakes.

Ackroyd and Harvey and UVA are speaking at the Academy on January 22 2010. For more details see Royal Academy of Arts.