9.7 out of 10 scientists agree that climate change is happening and that humans are to blame. Greenhouse gasses like carbon dioxide and methane that we've been pumping into the atmosphere have been capturing heat from the sun's rays, and average annual temperatures have been on the rise since the industrial revolution. The common wisdom is we need to drastically cut back the amount of greenhouse gasses we emit, but what if instead we just reduced the amount of sunlight we receive so greenhouse gasses can't soak up as much heat? 

If that sounds crazy to you, it's probably because it kind of is. Projects that would accomplish that would require engineering feats on a global scale, hence why it's called "geoengineering." Geoengineering ideas to fight climate change stretch all the way back to 1965 when science advisors to President Lyndon B Johnson proposed covering 13 millions square kilometers of ocean with reflective particles to bounce 1% of the sun's rays back into space. As you can tell by how un-fabulous our oceans are right now, we never ended up glitter bombing the Pacific.

But geoengineering ideas still crop up from time to time, lurking at the fringe of the climate change discussion. So, what are the most popular ideas and why haven't we put them into action yet?

Read More:

Scientific American: What Is Geoengineering and Why Is It Considered a Climate Change Solution?

LiveScience: Could Space Mirrors Stop Global Warming?

Seeker: A Massive Renewable Energy Push Is Needed to Avoid Catastrophic Climate Change