With the impending doom of climate change looming closer and closer, NGOs, nonprofits, and governments around the world are asking citizens to drive less, buy local, and "reduce, reuse, and recycle." However, there are certain places where these gestures may not be enough—cities where years of heavy industry, inefficient energy usage, and a lack of environmental regulation have contributed to massive pollution, non-potable water, and smog-drenched skies ( ah hem -  China).

Indeed, the situation in some areas is so dire that the United Nations' Intergovernmental Panel on Climate Change is on the brink of mandating governments to physically extract greenhouse gases from the air. But, other than simply planting a bunch of trees all over the place, how exactly does one do this?

With the heat from the UN—and with billionaire patrons like Richard Branson dangling a giant money-carrot—the race is on to develop innovative methods and technologies to assist in carbon dioxide removal. The scope of these concepts is vast, ranging from god-like weather control and geo-engineering efforts, to personal breathing-capsules and grassroots DIY filters.

Cloud-seeding is like a technically advanced form of the rain dance, inducing precipitation from the sky on a whim. Silver iodide, or dry ice, is introduced into the air by rocket or plane to stimulate cloud condensation, which then causes rain or snow. The largest existing system is currently in China, and was infamously used in the lead up to the Beijing Olympics in 2008 to clear some of the pollution from the air. Despite some concerns about the silver iodide, studies have found that it has negligible impact on humans' health or the environment.

Similar to cloud-seeding (but without the weather manipulation), a new proposal looks into the idea of installing giant sprinklers on skyscrapers. Releasing water particles into the air will help settle dust and pollution particles, much like "dust suppression units" used in the construction industry. This is still very much in the speculation stage—some concerns include cost, and whether this system could withstand storms and high winds—but even its skeptics have conceded that it's a pretty awesome, and plausible, idea.

Possibly the most controversial of all the proposals, geo-engineering is basically exactly what it sounds like: re-engineering the earth. To counteract our current excess of carbon dioxide, scientists have proposed measures ranging from fertilizing the oceans with iron to putting sulphur dioxide into the atmosphere. Yet many, including Al Gore, are skeptical about battling one substance with another, and there are wide-spread fears that the method will destroy ozone layers and increase acid rain.

A possible idea: smog-eating building surface.

The treatment is a thin layer of titanium dioxide (TiO2), a powder or liquid that can be applied to glass, concrete, metal, or fabric; when sunlight hits the chemically treated surface, a process begins that oxidizes organic matter, turning pollutants into water vapor and CO2.

The innovative technique has recently been used on the Manuel Gea González Hospital in Mexico City, one of the most polluted cities in the world. The façade was designed to use Prosolve 370e, a new system of thermoformed plastic shells are coated in TiO2 developed by Elegant Embellishments. The system blends sustainability with forward-thinking construction techniques and novel form: the developers used Rhino to fabricate five different modules, each shaped to maximize surface area, light reception, and wind resistance, and thus increase the benefits of the treatment.

Perhaps, in the future, every architectural surface will be working to improve air quality; these buildings might be the first steps toward that new world.