Green Maven: Green Maven is a search engine designed to specifically search the "green web." They focus on helping you find the best green, conscious, and sustainable web sites. There's also a Green Maven Firefox plugin to make those searches even easier.

Green Maven

Ecocho: Ecocho is a green search engine, which is essentially just a wrapper over Yahoo search. The site gives its users the opportunity to contribute to the purchase of carbon offsets by performing searches. For every 1000 searches, Ecocho grows two trees. They are not a charity, though - 30% of their revenue goes to running costs.

Ecocho

Blackle: Blackle takes everyone's favorite search engine, Google, and turns off the lights. By using a black background, Blacke saves energy since monitors require more power to display a white (or light) screen than a black (or dark) screen. How much energy is saved? Blackle references a blog post that claims that a black Google would save 750 Megawatt-hours per year.

Blackle

searchgreener: Like Blackle, searchgreener has a black background to use less energy. They also donate all profits to the purchase of carbon offsets.

Searchgreener

Eco-find: Another black-background search engine, Eco-find also uses Google search.

Eco-find

Earthle: Because apparently, we can't have enough darkened engines, Earthle also conserves energy.

Earthle

EcoSeek: The tagline at EcoSeek is "the search engine for all things green," but unlike Green Maven, EcoSeek is a product search focused engine. The site helps educate buyers and connect them to eco-friendly products, manufacturers, and retailers.

EcoSeek

Greensie: Another green search engine is Greensie, whose mission is to "organize and deliver the world's best information about green." Using the bullets below the search box, you can narrow your search to web, images, news, shopping, articles, videos, jobs, audio, or blogs.

Greensie

Greenona: Greenona is yet another green-focused engine that helps you connect with green resources on the web. Their site features many stats, like a large tag cloud of the past 500 searches and the top 100 clicked results.

Greenona

Green Link Central: Another attempt at a green-focused engine is Green Link Central. This one is the Mahalo of green engines, with every link hand-picked by human editors.

Green Link Central

Green Terrior: Green Terroir is a project of Green Consensus, a nonprofit organization that participates in land trusts and offers several services including carbon neutral web hosting, agribusiness consulting, and technological support for social entrepreneurs and fair-trade cooperatives. 100% of the profits of the web site go to land conservation activities and carbon offsets.

Green Terrior

EcoSeeker: It's not the best-looking of the green engines, but EcoSeeker is a one-woman effort, which is impressive. The site, made by Susan Landes of California, is a directory that helps you find green products, services, and info.

EcoSeeker

Friends Green: Friends Green is a simple search engine wrapper, with Yahoo search as the back-end. Proceeds from searches go towards fighting global warming by funding various reforestation projects. The site also tracks the amount of rainforest they've saved at the bottom of the main page via a constantly updating ticker (3,882,253 sq ft as of now).

Friends Green

greenlinking: Greenlinking.com is a search engine wrapper that lets you search using Google alone or by using the results from Yahoo, ninemsn, and Google combined. The site purchases carbon credits via Carbon Planet with the revenue they earn, which averages to an offset of 20 kg of greenhouse gases per user per month.

Greenlinking

ClimateGift: More than just a search engine, ClimateGift is an engine and portal for green content. When you first visit the site, you pick an organization to support before being redirected to the homepage. From then on, your chosen organization receives the money from your ad clicks. The site also functions very well as a personalized homepage, very much like iGoogle, with the ability to add tabs and content.

ClimateGift

Bonus: Google.co.uk users can add a Carbon Footprint tab to their personalized iGoogle homepage thanks to the UK Carbon Footprint Project. (Hey, where's ours?)