10 Scary Modern Technologies

Splinters of ice peel off from one side of the Perito Moreno glacier in southern Argentina in 2008. Dumping iron dust in the seas or placing smoke and mirrors in the sky to dim the sun could curb global warming, say backers of geoengineering. © STRINGER/ARGENTINA/Reuters/Corbis

The most important engineering innovations of the industrial age — motorized vehicles, electricity generation and industrial manufacturing — are the greatest sources of CO2 emissions [source: EPA]. Since world leaders appear unwilling or unable to take meaningful action to reduce greenhouse emissions, some maverick scientists are proposing a risky solution called geoengineering.

Geoengineering uses science and technology to "hack" the planet back into shape. Since global warming is the biggest threat, scientists are proposing creatively creepy (and very expensive) ways to artificially cool the atmosphere by either blocking the sun's rays or sucking up excess CO2. Among them [sources: Bullis, Kintisch and Madrigal]:

  • Spraying chemical aerosols like sulfur dioxide into the atmosphere to bounce a fraction of sunlight back into space
  • Pouring iron into the ocean to spur algae blooms that consume CO2
  • Spraying a mist of seawater into low-lying clouds to make them brighter, reflecting more sunlight
  • Planting forests of artificial trees that use chemical reactions to absorb and store CO2

Even geoengineering promoters warn of unintended side effects. Out-of-control algae blooms could create massive dead zones in the ocean; one nation's seawater spray could cause monsoons halfway around the world; chemical reactions could cause widespread damage to natural habitats and human life. Geoengineers argue there's just as much danger in doing nothing. By researching these techniques now, at least we'll have some hard data when it's time to push the panic button.

For our last scary technology, we consider a little thing called the Internet.