You may recall several months ago the media frenzy around the carbon footprint of a Google search. One scientist performed a calculation allocating about 3.5 grams of CO2 per search, a figure which Google hotly contested.

One search engine, Blackle, reduces this impact by simply making the screen all black with white letters, a simple feature which (according to their counter) has saved over 1.2 million of watt-hours of electricity to date.

Now a bevy of new green search engines is pushing the carbon-free searching envelope by contributing directly to the environment each time you search. A great top 10 list of green search engines was put together by Saikat Besu of MakeUseOf. Some of my favorites:

Forestle saves 1/10th of a meter of rainforest (about 4" x 4") per search, so in about 40,468 searches you could plant a whole acre. I probably do about 20 Google searches per day (7,200 per year) so in about 5 1/2 years I would save a whole acre of rainforest. Forestle does their rainforest protecting through a partnership with The Nature Conservancy.

Znout is from the same company but uses Google instead of Yahoo, and instead of rainforests they carbon-offset their IT energy consumption by using ad revenue to pay for REC's (or Renewable Energy Credits).

Green Planet Search is less functional but more slick. The website custom aggregates a wide variety of content including news, blogs and products.

GreenMaven curates the top content sources specifically targeting content for the eco-friendly. It has mapped over 10,000 sites and includes 4,000 business listings.

There are a bunch more. Check out the full post to learn about TrueVert, EcoSeek, ClimateGift and more.

Related posts:

Saving the planet one Internet search at a time
10 Web search engines that help the planet as you search.